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new 83bb3dd [BEAM-7700] Java transform catalog (#9129)
83bb3dd is described below
commit 83bb3ddbfb103796de8dc28525fc133472988163
Author: rosetn <40248483+ros...@users.noreply.github.com>
AuthorDate: Mon Jul 29 15:15:46 2019 -0700
[BEAM-7700] Java transform catalog (#9129)
* Java transform catalog
---
.../src/_includes/section-menu/documentation.html | 67 ++++++++-
.../java/aggregation/approximatequantiles.md | 43 ++++++
.../java/aggregation/approximateunique.md | 40 ++++++
.../transforms/java/aggregation/cogroupbykey.md | 73 ++++++++++
.../transforms/java/aggregation/combine.md | 82 +++++++++++
.../java/aggregation/combinewithcontext.md | 37 +++++
.../transforms/java/aggregation/count.md | 50 +++++++
.../transforms/java/aggregation/distinct.md | 43 ++++++
.../transforms/java/aggregation/groupbykey.md | 50 +++++++
.../java/aggregation/groupintobatches.md | 42 ++++++
.../transforms/java/aggregation/latest.md | 52 +++++++
.../transforms/java/aggregation/max.md | 56 ++++++++
.../transforms/java/aggregation/mean.md | 58 ++++++++
.../transforms/java/aggregation/min.md | 42 ++++++
.../transforms/java/aggregation/sample.md | 40 ++++++
.../transforms/java/aggregation/sum.md | 51 +++++++
.../transforms/java/aggregation/top.md | 39 ++++++
.../transforms/java/element-wise/filter.md | 62 +++++++++
.../java/element-wise/flatmapelements.md | 40 ++++++
.../transforms/java/element-wise/keys.md | 43 ++++++
.../transforms/java/element-wise/kvswap.md | 43 ++++++
.../transforms/java/element-wise/mapelements.md | 63 +++++++++
.../transforms/java/element-wise/pardo.md | 152 +++++++++++++++++++++
.../transforms/java/element-wise/partition.md | 62 +++++++++
.../transforms/java/element-wise/regex.md | 36 +++++
.../transforms/java/element-wise/reify.md | 39 ++++++
.../transforms/java/element-wise/tostring.md | 37 +++++
.../transforms/java/element-wise/values.md | 44 ++++++
.../transforms/java/element-wise/withkeys.md | 55 ++++++++
.../transforms/java/element-wise/withtimestamps.md | 36 +++++
website/src/documentation/transforms/java/index.md | 81 +++++++++++
.../documentation/transforms/java/other/create.md | 40 ++++++
.../documentation/transforms/java/other/flatten.md | 67 +++++++++
.../documentation/transforms/java/other/passert.md | 61 +++++++++
.../documentation/transforms/java/other/view.md | 37 +++++
.../documentation/transforms/java/other/window.md | 40 ++++++
36 files changed, 1900 insertions(+), 3 deletions(-)
diff --git a/website/src/_includes/section-menu/documentation.html
b/website/src/_includes/section-menu/documentation.html
index 8c7347a..0f26c36 100644
--- a/website/src/_includes/section-menu/documentation.html
+++ b/website/src/_includes/section-menu/documentation.html
@@ -138,8 +138,8 @@
<li><a href="{{ site.baseurl
}}/documentation/transforms/python/elementwise/regex/">Regex</a></li>
<li><a href="{{ site.baseurl
}}/documentation/transforms/python/elementwise/reify/">Reify</a></li>
<li><a href="{{ site.baseurl
}}/documentation/transforms/python/elementwise/tostring/">ToString</a></li>
- <li><a href="{{ site.baseurl
}}/documentation/transforms/python/elementwise/withtimestamps/">WithTimestamps</a></li>
- <li><a href="{{ site.baseurl
}}/documentation/transforms/python/elementwise/values/">Values</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/python/elementwise/values/">Values</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/python/elementwise/withtimestamps/">WithTimestamps</a></li>
</ul>
</li>
<li class="section-nav-item--collapsible">
@@ -168,7 +168,68 @@
</li>
</ul>
</li>
- </ul>
+
+ <li class="section-nav-item--collapsible">
+ <span class="section-nav-list-title">Java</span>
+
+ <ul class="section-nav-list">
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/overview/">Overview</a></li>
+ <li class="section-nav-item--collapsible">
+ <span class="section-nav-list-title">Element-wise</span>
+
+ <ul class="section-nav-list">
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/elementwise/filter/">Filter</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/elementwise/flatmapelements/">FlatMapElements</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/elementwise/keys/">Keys</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/elementwise/kvswap/">KvSwap</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/elementwise/mapelements/">MapElements</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/elementwise/pardo/">ParDo</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/elementwise/partition/">Partition</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/elementwise/regex/">Regex</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/elementwise/reify/">Reify</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/elementwise/values/">Values</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/elementwise/tostring/">ToString</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/elementwise/withkeys/">WithKeys</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/elementwise/withtimestamps/">WithTimestamps</a></li>
+ </ul>
+ </li>
+ <li class="section-nav-item--collapsible">
+ <span class="section-nav-list-title">Aggregation</span>
+
+ <ul class="section-nav-list">
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/approximatequantiles/">ApproximateQuantiles</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/approximateunique/">ApproximateUnique</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/cogroupbykey/">CoGroupByKey</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/combine/">Combine</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/combinewithcontext/">CombineWithContext</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/count/">Count</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/distinct/">Distinct</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/groupbykey/">GroupByKey</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/groupintobatches/">GroupIntoBatches</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/latest/">Latest</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/max/">Max</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/mean/">Mean</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/min/">Min</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/sample/">Sample</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/sum/">Sum</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/top/">Top</a></li>
+ </ul>
+ </li>
+ <li class="section-nav-item--collapsible">
+ <span class="section-nav-list-title">Other</span>
+
+ <ul class="section-nav-list">
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/other/create/">Create</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/other/flatten/">Flatten</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/other/passert/">PAssert</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/other/view/">View</a></li>
+ <li><a href="{{ site.baseurl
}}/documentation/transforms/java/other/window/">Window</a></li>
+ </ul>
+ </li>
+ </ul>
+ </li>
+ </ul>
+
</li>
<li class="section-nav-item--collapsible">
diff --git
a/website/src/documentation/transforms/java/aggregation/approximatequantiles.md
b/website/src/documentation/transforms/java/aggregation/approximatequantiles.md
new file mode 100644
index 0000000..561cca0
--- /dev/null
+++
b/website/src/documentation/transforms/java/aggregation/approximatequantiles.md
@@ -0,0 +1,43 @@
+---
+layout: section
+title: "ApproximateQuantiles"
+permalink: /documentation/transforms/java/aggregation/approximatequantiles/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# ApproximateQuantiles
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/ApproximateQuantiles.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Takes a comparison function and the desired number of quantiles *n*, either
+globally or per-key. Using an approximation algorithm, it returns the
+minimum value, *n-2* intermediate values, and the maximum value.
+
+## Examples
+**Example**: to compute the quartiles of a `PCollection` of integers, we
+would use `ApproximateQuantiles.globally(5)`. This will produce a list
+containing 5 values: the minimum value, Quartile 1 value, Quartile 2
+value, Quartile 3 value, and the maximum value.
+
+## Related transforms
+* [ApproximateUnique]({{ site.baseurl
}}/documentation/transforms/java/aggregation/approximateunique)
+ estimates the number of distinct elements or distinct values in key-value
pairs
+* [Combine]({{ site.baseurl
}}/documentation/transforms/java/aggregation/combine)
\ No newline at end of file
diff --git
a/website/src/documentation/transforms/java/aggregation/approximateunique.md
b/website/src/documentation/transforms/java/aggregation/approximateunique.md
new file mode 100644
index 0000000..9b3e6d0
--- /dev/null
+++ b/website/src/documentation/transforms/java/aggregation/approximateunique.md
@@ -0,0 +1,40 @@
+---
+layout: section
+title: "ApproximateUnique"
+permalink: /documentation/transforms/java/aggregation/approximateunique/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# ApproximateUnique
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/ApproximateUnique.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Transforms for estimating the number of distinct elements in a collection
+or the number of distinct values associated with each key in a collection
+of key-value pairs.
+
+## Examples
+See [BEAM-7703](https://issues.apache.org/jira/browse/BEAM-7703) for updates.
+
+## Related transforms
+* [Count]({{ site.baseurl }}/documentation/transforms/java/aggregation/count)
+ counts the number of elements within each aggregation.
+* [Distinct]({{ site.baseurl
}}/documentation/transforms/java/aggregation/distinct)
\ No newline at end of file
diff --git
a/website/src/documentation/transforms/java/aggregation/cogroupbykey.md
b/website/src/documentation/transforms/java/aggregation/cogroupbykey.md
new file mode 100644
index 0000000..a546058
--- /dev/null
+++ b/website/src/documentation/transforms/java/aggregation/cogroupbykey.md
@@ -0,0 +1,73 @@
+---
+layout: section
+title: "CoGroupByKey"
+permalink: /documentation/transforms/java/aggregation/cogroupbykey/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# CoGroupByKey
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/join/CoGroupByKey.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Aggregates all input elements by their key and allows downstream processing
+to consume all values associated with the key. While `GroupByKey` performs
+this operation over a single input collection and thus a single type of
+input values, `CoGroupByKey` operates over multiple input collections. As
+a result, the result for each key is a tuple of the values associated with
+that key in each input collection.
+
+See more information in the [Beam Programming Guide]({{ site.baseurl
}}/documentation/programming-guide/#cogroupbykey).
+
+## Examples
+**Example**: Say you have two different files with user data; one file has
+names and email addresses and the other file has names and phone numbers.
+
+You can join those two data sets, using the username as a common key and the
+other data as the associated values. After the join, you have one data set
+that contains all of the information (email addresses and phone numbers)
+associated with each name.
+
+```java
+PCollection<KV<UID, Integer>> pt1 = /* ... */;
+PCollection<KV<UID, String>> pt2 = /* ... */;
+
+final TupleTag<Integer> t1 = new TupleTag<>();
+final TupleTag<String> t2 = new TupleTag<>();
+PCollection<KV<UID, CoGBKResult>> result =
+ KeyedPCollectionTuple.of(t1, pt1).and(t2, pt2)
+ .apply(CoGroupByKey.create());
+result.apply(ParDo.of(new DoFn<KV<K, CoGbkResult>, /* some result */>() {
+ @ProcessElement
+ public void processElement(ProcessContext c) {
+ KV<K, CoGbkResult> e = c.element();
+ CoGbkResult result = e.getValue();
+ // Retrieve all integers associated with this key from pt1
+ Iterable<Integer> allIntegers = result.getAll(t1);
+ // Retrieve the string associated with this key from pt2.
+ // Note: This will fail if multiple values had the same key in pt2.
+ String string = e.getOnly(t2);
+ ...
+}));
+```
+
+## Related transforms
+* [GroupByKey]({{ site.baseurl
}}/documentation/transforms/java/aggregation/groupbykey)
+ takes one input collection.
\ No newline at end of file
diff --git a/website/src/documentation/transforms/java/aggregation/combine.md
b/website/src/documentation/transforms/java/aggregation/combine.md
new file mode 100644
index 0000000..3bca34b
--- /dev/null
+++ b/website/src/documentation/transforms/java/aggregation/combine.md
@@ -0,0 +1,82 @@
+---
+layout: section
+title: "Combine"
+permalink: /documentation/transforms/java/aggregation/combine/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# Combine
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/Combine.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+A user-defined `CombineFn` may be applied to combine all elements in a
+`PCollection` (global combine) or to combine all elements associated
+with each key.
+
+While the result is similar to applying a `GroupByKey` followed by
+aggregating values in each `Iterable`, there is an impact
+on the code you must write as well as the performance of the pipeline.
+Writing a `ParDo` that counts the number of elements in each value
+would be very straightforward. However, as described in the execution
+model, it would also require all values associated with each key to be
+processed by a single worker. This introduces a lot of communication overhead.
+Using a `CombineFn` requires the code be structured as an associative and
+commumative operation. But, it allows the use of partial sums to be
precomputed.
+
+See more information in the [Beam Programming Guide]({{ site.baseurl
}}/documentation/programming-guide/#combine).
+
+## Examples
+**Example 1**: Global combine
+Use the global combine to combine all of the elements in a given `PCollection`
+into a single value, represented in your pipeline as a new `PCollection`
containing
+one element. The following example code shows how to apply the Beam-provided
+sum combine function to produce a single sum value for a `PCollection` of
integers.
+
+```java
+// Sum.SumIntegerFn() combines the elements in the input PCollection. The
resulting PCollection, called sum,
+// contains one value: the sum of all the elements in the input PCollection.
+PCollection<Integer> pc = ...;
+PCollection<Integer> sum = pc.apply(
+ Combine.globally(new Sum.SumIntegerFn()));
+```
+
+**Example 2**: Keyed combine
+Use a keyed combine to to combine all of the values associated with each key
+into a single output value for each key. As with the global combine, the
+function passed to a keyed combine must be associative and commutative.
+
+```java
+// PCollection is grouped by key and the Double values associated with each
key are combined into a Double.
+PCollection<KV<String, Double>> salesRecords = ...;
+PCollection<KV<String, Double>> totalSalesPerPerson =
+ salesRecords.apply(Combine.<String, Double, Double>perKey(
+ new Sum.SumDoubleFn()));
+// The combined value is of a different type than the original collection of
values per key. PCollection has
+// keys of type String and values of type Integer, and the combined value is a
Double.
+PCollection<KV<String, Integer>> playerAccuracy = ...;
+PCollection<KV<String, Double>> avgAccuracyPerPlayer =
+ playerAccuracy.apply(Combine.<String, Integer, Double>perKey(
+ new MeanInts())));
+```
+
+## Related transforms
+* [CombineWithContext]({{ site.baseurl
}}/documentation/transforms/java/aggregation/combinewithcontext)
+* [GroupByKey]({{ site.baseurl
}}/documentation/transforms/java/aggregation/groupbykey)
\ No newline at end of file
diff --git
a/website/src/documentation/transforms/java/aggregation/combinewithcontext.md
b/website/src/documentation/transforms/java/aggregation/combinewithcontext.md
new file mode 100644
index 0000000..20f29dd
--- /dev/null
+++
b/website/src/documentation/transforms/java/aggregation/combinewithcontext.md
@@ -0,0 +1,37 @@
+---
+layout: section
+title: "CombineWithContext"
+permalink: /documentation/transforms/java/aggregation/combinewithcontext/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# CombineWithContext
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/curent/index.html?org/apache/beam/sdk/transforms/CombineWithContext.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+A class of transforms that contains combine functions that have access to
`PipelineOptions` and side inputs through `CombineWithContext.Context`.
+
+## Examples
+See [BEAM-7703](https://issues.apache.org/jira/browse/BEAM-7703) for updates.
+
+## Related transforms
+* [Combine]({{ site.baseurl
}}/documentation/transforms/java/aggregation/combine)
+ for combining all values associated with a key to a single result
\ No newline at end of file
diff --git a/website/src/documentation/transforms/java/aggregation/count.md
b/website/src/documentation/transforms/java/aggregation/count.md
new file mode 100644
index 0000000..17b9ff7
--- /dev/null
+++ b/website/src/documentation/transforms/java/aggregation/count.md
@@ -0,0 +1,50 @@
+---
+layout: section
+title: "Count"
+permalink: /documentation/transforms/java/aggregation/count/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# Count
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/Count.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Counts the number of elements within each aggregation. The `Count`
+transform has three varieties:
+
+* `Count.globally()` counts the number of elements in the entire
+ `PCollection`. The result is a collection with a single element.
+* `Count.perKey()` counts how many elements are associated with each
+ key. It ignores the values. The resulting collection has one
+ output for every key in the input collection.
+* `Count.perElement()` counts how many times each element appears
+ in the input collection. The output collection is a key-value
+ pair, containing each unique element and the number of times it
+ appeared in the original collection.
+
+## Examples
+See [BEAM-7703](https://issues.apache.org/jira/browse/BEAM-7703) for updates.
+
+## Related transforms
+* [ApproximateUnique]({{ site.baseurl
}}/documentation/transforms/java/aggregation/approximateunique)
+ estimates the number of distinct elements or distinct values in key-value
pairs
+* [Sum]({{ site.baseurl }}/documentation/transforms/java/aggregation/sum)
computes
+ the sum of elements in a collection
\ No newline at end of file
diff --git a/website/src/documentation/transforms/java/aggregation/distinct.md
b/website/src/documentation/transforms/java/aggregation/distinct.md
new file mode 100644
index 0000000..08a3bcd
--- /dev/null
+++ b/website/src/documentation/transforms/java/aggregation/distinct.md
@@ -0,0 +1,43 @@
+---
+layout: section
+title: "Distinct"
+permalink: /documentation/transforms/java/aggregation/distinct/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# Distinct
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/Distinct.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Produces a collection containing distinct elements of the input collection.
+
+On some data sets, it might be more efficient to compute an approximate
+answer using `ApproximateUnique`, which also allows for determining distinct
+values for each key.
+
+## Examples
+See [BEAM-7703](https://issues.apache.org/jira/browse/BEAM-7703) for updates.
+
+## Related transforms
+* [Count]({{ site.baseurl }}/documentation/transforms/java/aggregation/count)
+ counts the number of elements within each aggregation.
+* [ApproximateUnique]({{ site.baseurl
}}/documentation/transforms/java/aggregation/approximateunique)
+ estimates the number of distinct elements in a collection.
\ No newline at end of file
diff --git
a/website/src/documentation/transforms/java/aggregation/groupbykey.md
b/website/src/documentation/transforms/java/aggregation/groupbykey.md
new file mode 100644
index 0000000..f73cb4f
--- /dev/null
+++ b/website/src/documentation/transforms/java/aggregation/groupbykey.md
@@ -0,0 +1,50 @@
+---
+layout: section
+title: "GroupByKey"
+permalink: /documentation/transforms/java/aggregation/groupbykey/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# GroupByKey
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/GroupByKey.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Takes a keyed collection of elements and produces a collection where
+each element consists of a key and an `Iterable` of all values
+associated with that key.
+
+The results can be combined with windowing to subdivide each key
+based on time or triggering to produce partial aggregations. Either
+windowing or triggering is necessary when processing unbounded collections.
+
+See more information in the [Beam Programming Guide]({{ site.baseurl
}}/documentation/programming-guide/#groupbykey).
+
+## Examples
+**Example 1**: (a, 1), (b, 2), (a, 3) will result into (a, [1, 3]), (b, [2]).
+
+**Example 2**: Given a collection of customer orders keyed by postal code,
+you could use `GroupByKey` to get the collection of all orders in each postal
code.
+
+## Related transforms
+* [CoGroupByKey]({{ site.baseurl
}}/documentation/transforms/java/aggregation/cogroupbykey)
+ for multiple input collections
+* [Combine]({{ site.baseurl
}}/documentation/transforms/java/aggregation/combine)
+ for combining all values associated with a key to a single result
\ No newline at end of file
diff --git
a/website/src/documentation/transforms/java/aggregation/groupintobatches.md
b/website/src/documentation/transforms/java/aggregation/groupintobatches.md
new file mode 100644
index 0000000..8874648
--- /dev/null
+++ b/website/src/documentation/transforms/java/aggregation/groupintobatches.md
@@ -0,0 +1,42 @@
+---
+layout: section
+title: "GroupIntoBatches"
+permalink: /documentation/transforms/java/aggregation/groupintobatches/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# GroupIntoBatches
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/GroupIntoBatches.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Batches inputs to a desired batch size.
+
+Batches contain only elements of a single key. Elements are buffered until
+`batchSize` number of elements buffered. Then, these elements are output
+to the output collection.
+
+Batches contain elements from the same window, so windows are preserved.
Batches might contain elements from more than one bundle.
+
+## Examples
+See [BEAM-7703](https://issues.apache.org/jira/browse/BEAM-7703) for updates.
+
+## Related transforms
+* [GroupByKey]({{ site.baseurl
}}/documentation/transforms/java/aggregation/groupbykey) takes one input
collection.
\ No newline at end of file
diff --git a/website/src/documentation/transforms/java/aggregation/latest.md
b/website/src/documentation/transforms/java/aggregation/latest.md
new file mode 100644
index 0000000..a2ed7a5
--- /dev/null
+++ b/website/src/documentation/transforms/java/aggregation/latest.md
@@ -0,0 +1,52 @@
+---
+layout: section
+title: "Latest"
+permalink: /documentation/transforms/java/aggregation/latest/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# Latest
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/Latest.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+A transform and `Combine.CombineFn` for computing the latest element in a
collection.
+
+* `Latest.globally()` takes a collection of values and produces the collection
+ containing the single value with the latest implicit timestamp.
+* `Latest.perKey()` takes a collection of key value pairs, and returns the
+ latest value for each key, according to the implicit timestamp.
+
+For elements with the same timestamp, the output element is arbitrarily
selected.
+
+## Examples
+**Example**: compute the latest value for each session
+```java
+ PCollection input = ...;
+ PCollection sessioned = input
+ .apply(Window.into(Sessions.withGapDuration(Duration.standardMinutes(5)));
+ PCollection latestValues = sessioned.apply(Latest.globally());
+```
+
+## Related transforms
+* [Reify]({{ site.baseurl }}/documentation/transforms/java/elementwise/reify)
+ converts between explicit and implicit form of various Beam values
+* [WithTimestamps]({{ site.baseurl
}}/documentation/transforms/java/elementwise/withtimestamps)
+ assigns timestamps to all the elements of a collection
diff --git a/website/src/documentation/transforms/java/aggregation/max.md
b/website/src/documentation/transforms/java/aggregation/max.md
new file mode 100644
index 0000000..941647f
--- /dev/null
+++ b/website/src/documentation/transforms/java/aggregation/max.md
@@ -0,0 +1,56 @@
+---
+layout: section
+title: "Max"
+permalink: /documentation/transforms/java/aggregation/max/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# Max
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/Max.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Provides a variety of different transforms for computing the maximum
+values in a collection, either globally or for each key.
+
+## Examples
+**Example 1**: get the maximum of a `PCollection` of `Doubles`.
+
+```java
+PCollection<Double> input = ...;
+PCollection<Double> max = input.apply(Max.doublesGlobally());
+```
+
+**Example 2**: calculate the maximum of the `Integers` associated
+with each unique key (which is of type `String`).
+
+```java
+PCollection<KV<String, Integer>> input = ...;
+PCollection<KV<String, Integer>> maxPerKey = input
+ .apply(Max.integersPerKey());
+```
+
+## Related transforms
+* [Min]({{ site.baseurl }}/documentation/transforms/java/aggregation/min)
+ for computing minimum values in a collection
+* [Mean]({{ site.baseurl }}/documentation/transforms/java/aggregation/mean)
+ for computing the arithmetic mean of the elements in a collection
+* [Combine]({{ site.baseurl
}}/documentation/transforms/java/aggregation/combine)
+ for combining all values associated with a key to a single result
\ No newline at end of file
diff --git a/website/src/documentation/transforms/java/aggregation/mean.md
b/website/src/documentation/transforms/java/aggregation/mean.md
new file mode 100644
index 0000000..36b487e
--- /dev/null
+++ b/website/src/documentation/transforms/java/aggregation/mean.md
@@ -0,0 +1,58 @@
+---
+layout: section
+title: "Mean"
+permalink: /documentation/transforms/java/aggregation/mean/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# Mean
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/Mean.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Transforms for computing the arithmetic mean of the elements in a collection,
+or the mean of the values associated with each key in a collection of
key-value pairs.
+
+* `Mean.globally()` returns a transform that then returns a collection whose
contents is the mean of the input collection's elements. If there are no
elements in the input collection, it returns 0.
+* `Mean.perKey()` returns a transform that returns a collection that contains
an output element mapping each distinct key in the input collection to the mean
of the values associated with that key in the input collection.
+
+## Examples
+**Example 1**: get the mean of a `PCollection` of `Longs`.
+
+```java
+PCollection<Double> input = ...;
+PCollection<Double> mean = input.apply(Mean.globally());
+```
+
+**Example 2**: calculate the mean of the `Integers` associated with each
unique key (which is of type `String`).
+
+```java
+PCollection<KV<String, Integer>> input = ...;
+PCollection<KV<String, Integer>> meanPerKey =
+ input.apply(Mean.perKey());
+```
+
+## Related transforms
+* [Max]({{ site.baseurl }}/documentation/transforms/java/aggregation/max)
+ for computing maximum values in a collection
+* [Min]({{ site.baseurl }}/documentation/transforms/java/aggregation/min)
+ for computing maximum values in a collection
+* [Combine]({{ site.baseurl
}}/documentation/transforms/java/aggregation/combine)
+ for combining all values associated with a key to a single result
\ No newline at end of file
diff --git a/website/src/documentation/transforms/java/aggregation/min.md
b/website/src/documentation/transforms/java/aggregation/min.md
new file mode 100644
index 0000000..538b02f
--- /dev/null
+++ b/website/src/documentation/transforms/java/aggregation/min.md
@@ -0,0 +1,42 @@
+---
+layout: section
+title: "Min"
+permalink: /documentation/transforms/java/aggregation/min/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# Min
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/Min.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Provides a variety of different transforms for computing the minimum
+values in a collection, either globally or for each key.
+
+## Examples
+See [BEAM-7703](https://issues.apache.org/jira/browse/BEAM-7703) for updates.
+
+## Related transforms
+* [Max]({{ site.baseurl }}/documentation/transforms/java/aggregation/max)
+ for computing maximum values in a collection
+* [Mean]({{ site.baseurl }}/documentation/transforms/java/aggregation/mean)
+ for computing the arithmetic mean of the elements in a collection
+* [Combine]({{ site.baseurl
}}/documentation/transforms/java/aggregation/combine)
+ for combining all values associated with a key to a single result
\ No newline at end of file
diff --git a/website/src/documentation/transforms/java/aggregation/sample.md
b/website/src/documentation/transforms/java/aggregation/sample.md
new file mode 100644
index 0000000..6f7e181
--- /dev/null
+++ b/website/src/documentation/transforms/java/aggregation/sample.md
@@ -0,0 +1,40 @@
+---
+layout: section
+title: "Sample"
+permalink: /documentation/transforms/java/aggregation/sample/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# Sample
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/org/apache/beam/sdk/transforms/Sample.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Transforms for taking samples of the elements in a collection, or
+samples of the values associated with each key in a collection of key-value
pairs.
+
+## Examples
+See [BEAM-7703](https://issues.apache.org/jira/browse/BEAM-7703) for updates.
+
+## Related transforms
+* [Top]({{ site.baseurl }}/documentation/transforms/java/aggregation/top)
+ finds the largest (or smallest) set of elements in a collection
+* [Latest]({{ site.baseurl }}/documentation/transforms/java/aggregation/latest)
+ computes the latest element in a collection
\ No newline at end of file
diff --git a/website/src/documentation/transforms/java/aggregation/sum.md
b/website/src/documentation/transforms/java/aggregation/sum.md
new file mode 100644
index 0000000..ee1f282
--- /dev/null
+++ b/website/src/documentation/transforms/java/aggregation/sum.md
@@ -0,0 +1,51 @@
+---
+layout: section
+title: "Sum"
+permalink: /documentation/transforms/java/aggregation/sum/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# Sum
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/Sum.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Transforms for computing the sum of the elements in a collection, or the sum
of the
+values associated with each key in a collection of key-value pairs.
+
+## Examples
+**Example 1**: get the sum of a `PCollection` of `Doubles`.
+
+```java
+PCollection<Double> input = ...;
+PCollection<Double> sum = input.apply(Sum.doublesGlobally());
+```
+
+Example 2: calculate the sum of the `Integers` associated with each unique key
(which is of type `String`).
+
+```java
+PCollection<KV<String, Integer>> input = ...;
+PCollection<KV<String, Integer>> sumPerKey = input
+ .apply(Sum.integersPerKey());
+```
+
+## Related transforms
+* [Count]({{ site.baseurl }}/documentation/transforms/java/aggregation/count)
+ counts the number of elements within each aggregation
\ No newline at end of file
diff --git a/website/src/documentation/transforms/java/aggregation/top.md
b/website/src/documentation/transforms/java/aggregation/top.md
new file mode 100644
index 0000000..7f060f1
--- /dev/null
+++ b/website/src/documentation/transforms/java/aggregation/top.md
@@ -0,0 +1,39 @@
+---
+layout: section
+title: "Top"
+permalink: /documentation/transforms/java/aggregation/top/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# Top
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/Top.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Transforms for finding the largest (or smallest) set of elements in
+a collection, or the largest (or smallest) set of values associated
+with each key in a collection of key-value pairs.
+
+## Examples
+See [BEAM-7703](https://issues.apache.org/jira/browse/BEAM-7703) for updates.
+
+## Related transforms
+* [Sample]({{ site.baseurl }}/documentation/transforms/java/aggregation/sample)
+ takes samples of collection
\ No newline at end of file
diff --git a/website/src/documentation/transforms/java/element-wise/filter.md
b/website/src/documentation/transforms/java/element-wise/filter.md
new file mode 100644
index 0000000..975fa09
--- /dev/null
+++ b/website/src/documentation/transforms/java/element-wise/filter.md
@@ -0,0 +1,62 @@
+---
+layout: section
+title: "Filter"
+permalink: /documentation/transforms/java/elementwise/filter/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# Filter
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/Filter.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Given a predicate, filter out all elements that don't satisfy that predicate.
+May also be used to filter based on an inequality with a given value based
+on the natural ordering of the element.
+
+## Examples
+**Example 1**: Filtering with a predicate
+
+```java
+PCollection<String> allStrings = Create.of("Hello", "world", "hi");
+PCollection<String> longStrings = allStrings
+ .apply(Filter.by(new SerializableFunction<String, Boolean>() {
+ @Override
+ public Boolean apply(String input) {
+ return input.length() > 3;
+ }
+ }));
+```
+The result is a `PCollection` containing "Hello" and "world".
+
+**Example 2**: Filtering with an inequality
+
+```java
+PCollection<Long> numbers = Create.of(1L, 2L, 3L, 4L, 5L);
+PCollection<Long> bigNumbers = numbers.apply(Filter.greaterThan(3));
+PCollection<Long> smallNumbers = numbers.apply(Filter.lessThanEq(3));
+```
+Other variants include `Filter.greaterThanEq`, `Filter.lessThan` and
`Filter.equal`.
+
+## Related transforms
+* [FlatMapElements]({{ site.baseurl
}}/documentation/transforms/java/elementwise/flatmapelements) behaves the same
as `Map`, but for
+ each input it might produce zero or more outputs.
+* [ParDo]({{ site.baseurl }}/documentation/transforms/java/elementwise/pardo)
is the most general element-wise mapping
+ operation, and includes other abilities such as multiple output collections
and side-inputs.
\ No newline at end of file
diff --git
a/website/src/documentation/transforms/java/element-wise/flatmapelements.md
b/website/src/documentation/transforms/java/element-wise/flatmapelements.md
new file mode 100644
index 0000000..62fe930
--- /dev/null
+++ b/website/src/documentation/transforms/java/element-wise/flatmapelements.md
@@ -0,0 +1,40 @@
+---
+layout: section
+title: "FlatMapElements"
+permalink: /documentation/transforms/java/elementwise/flatmapelements/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# FlatMapElements
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/FlatMapElements.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Applies a simple 1-to-many mapping function over each element in the
+collection. The many elements are flattened into the resulting collection.
+
+## Examples
+See [BEAM-7702](https://issues.apache.org/jira/browse/BEAM-7702) for updates.
+
+## Related transforms
+* [Filter]({{ site.baseurl
}}/documentation/transforms/java/elementwise/filter) is useful if the function
is just
+ deciding whether to output an element or not.
+* [ParDo]({{ site.baseurl }}/documentation/transforms/java/elementwise/pardo)
is the most general element-wise mapping
+ operation, and includes other abilities such as multiple output collections
and side-inputs.
\ No newline at end of file
diff --git a/website/src/documentation/transforms/java/element-wise/keys.md
b/website/src/documentation/transforms/java/element-wise/keys.md
new file mode 100644
index 0000000..b0d0738
--- /dev/null
+++ b/website/src/documentation/transforms/java/element-wise/keys.md
@@ -0,0 +1,43 @@
+---
+layout: section
+title: "Keys"
+permalink: /documentation/transforms/java/elementwise/keys/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# Keys
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/Keys.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Takes a collection of key-value pairs, and returns the key of each element.
+
+## Examples
+**Example**
+
+```java
+PCollection<KV<String, Integer>> keyValuePairs = /* ... */;
+PCollection<String> keys = keyValuePairs.apply(Keys.create());
+```
+
+## Related transforms
+* [KvSwap]({{ site.baseurl
}}/documentation/transforms/java/elementwise/kvswap) swaps key-value pair
values.
+* [Values]({{ site.baseurl
}}/documentation/transforms/java/elementwise/values) for extracting the value
of each element.
+* [WithKeys]({{ site.baseurl
}}/documentation/transforms/java/elementwise/withkeys) for adding a key to each
element.
\ No newline at end of file
diff --git a/website/src/documentation/transforms/java/element-wise/kvswap.md
b/website/src/documentation/transforms/java/element-wise/kvswap.md
new file mode 100644
index 0000000..96a423c
--- /dev/null
+++ b/website/src/documentation/transforms/java/element-wise/kvswap.md
@@ -0,0 +1,43 @@
+---
+layout: section
+title: "KvSwap"
+permalink: /documentation/transforms/java/elementwise/kvswap/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# KvSwap
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/KvSwap.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Takes a collection of key-value pairs and returns a collection of key-value
pairs which has each key and value swapped.
+
+## Examples
+**Example**:
+
+```java
+PCollection<KV<String, Integer>> strIntPairs = /* ... */;
+PCollection<KV<Integer, String>> intStrPairs =
strIntPairs.apply(KvSwap.create());
+```
+
+## Related transforms
+* [Keys]({{ site.baseurl }}/documentation/transforms/java/elementwise/keys)
for extracting the key of each component.
+* [Values]({{ site.baseurl
}}/documentation/transforms/java/elementwise/values) for extracting the value
of each element.
+* [WithKeys]({{ site.baseurl
}}/documentation/transforms/java/elementwise/withkeys) for adding a key to each
element.
\ No newline at end of file
diff --git
a/website/src/documentation/transforms/java/element-wise/mapelements.md
b/website/src/documentation/transforms/java/element-wise/mapelements.md
new file mode 100644
index 0000000..e916e2e
--- /dev/null
+++ b/website/src/documentation/transforms/java/element-wise/mapelements.md
@@ -0,0 +1,63 @@
+---
+layout: section
+title: "MapElements"
+permalink: /documentation/transforms/java/elementwise/mapelements/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# MapElements
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/MapElements.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Applies a simple 1-to-1 mapping function over each element in the collection.
+
+## Examples
+**Example 1**: providing the mapping function using a `SimpleFunction`
+
+```java
+PCollection<String> lines = Create.of("Hello World", "Beam is fun");
+PCollection<Integer> lineLengths = lines.apply(MapElements.via(
+ new SimpleFunction<String, Integer>() {
+ @Override
+ public Integer apply(String line) {
+ return line.length();
+ }
+ });
+```
+
+**Example 2**: providing the mapping function using a `SerializableFunction`,
+which allows the use of Java 8 lambdas. Due to type erasure, you need
+to provide a hint indicating the desired return type.
+
+```java
+PCollection<String> lines = Create.of("Hello World", "Beam is fun");
+PCollection<Integer> lineLengths = lines.apply(MapElements
+ .into(TypeDescriptors.integers())
+ .via((String line) -> line.length()));
+```
+
+## Related transforms
+* [FlatMapElements]({{ site.baseurl
}}/documentation/transforms/java/elementwise/flatmapelements) behaves the same
as `Map`, but for
+ each input it may produce zero or more outputs.
+* [Filter]({{ site.baseurl
}}/documentation/transforms/java/elementwise/filter) is useful if the function
is just
+ deciding whether to output an element or not.
+* [ParDo]({{ site.baseurl }}/documentation/transforms/java/elementwise/pardo)
is the most general element-wise mapping
+ operation, and includes other abilities such as multiple output collections
and side-inputs.
\ No newline at end of file
diff --git a/website/src/documentation/transforms/java/element-wise/pardo.md
b/website/src/documentation/transforms/java/element-wise/pardo.md
new file mode 100644
index 0000000..3a7b979
--- /dev/null
+++ b/website/src/documentation/transforms/java/element-wise/pardo.md
@@ -0,0 +1,152 @@
+---
+layout: section
+title: "ParDo"
+permalink: /documentation/transforms/java/elementwise/pardo/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# ParDo
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/ParDo.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+A transform for generic parallel processing. A `ParDo` transform considers each
+element in the input `PCollection`, performs some processing function
+(your user code) on that element, and emits zero or more elements to
+an output PCollection.
+
+See more information in the [Beam Programming Guide]({{ site.baseurl
}}/documentation/programming-guide/#pardo).
+
+## Examples
+**Example 1**: Passing side inputs
+
+```java
+ // Pass side inputs to your ParDo transform by invoking .withSideInputs.
+ // Inside your DoFn, access the side input by using the method
DoFn.ProcessContext.sideInput.
+
+ // The input PCollection to ParDo.
+ PCollection<String> words = ...;
+
+ // A PCollection of word lengths that we'll combine into a single value.
+ PCollection<Integer> wordLengths = ...; // Singleton PCollection
+
+ // Create a singleton PCollectionView from wordLengths using
Combine.globally and View.asSingleton.
+ final PCollectionView<Integer> maxWordLengthCutOffView =
+ wordLengths.apply(Combine.globally(new Max.MaxIntFn()).asSingletonView());
+
+
+ // Apply a ParDo that takes maxWordLengthCutOffView as a side input.
+ PCollection<String> wordsBelowCutOff =
+ words.apply(ParDo
+ .of(new DoFn<String, String>() {
+ public void processElement(ProcessContext c) {
+ String word = c.element();
+ // In our DoFn, access the side input.
+ int lengthCutOff = c.sideInput(maxWordLengthCutOffView);
+ if (word.length() <= lengthCutOff) {
+ c.output(word);
+ }
+ }
+ }).withSideInputs(maxWordLengthCutOffView)
+ );
+```
+
+**Example 2**: Emitting to multiple outputs in your `DoFn`
+
+```java
+// To emit elements to multiple output PCollections, create a TupleTag object
to identify each collection
+// that your ParDo produces. For example, if your ParDo produces three output
PCollections (the main output
+// and two additional outputs), you must create three TupleTags. The following
example code shows how to
+// create TupleTags for a ParDo with three output PCollections.
+
+ // Input PCollection to our ParDo.
+ PCollection<String> words = ...;
+
+ // The ParDo will filter words whose length is below a cutoff and add them to
+ // the main ouput PCollection<String>.
+ // If a word is above the cutoff, the ParDo will add the word length to an
+ // output PCollection<Integer>.
+ // If a word starts with the string "MARKER", the ParDo will add that word
to an
+ // output PCollection<String>.
+ final int wordLengthCutOff = 10;
+
+ // Create three TupleTags, one for each output PCollection.
+ // Output that contains words below the length cutoff.
+ final TupleTag<String> wordsBelowCutOffTag =
+ new TupleTag<String>(){};
+ // Output that contains word lengths.
+ final TupleTag<Integer> wordLengthsAboveCutOffTag =
+ new TupleTag<Integer>(){};
+ // Output that contains "MARKER" words.
+ final TupleTag<String> markedWordsTag =
+ new TupleTag<String>(){};
+
+// Passing Output Tags to ParDo:
+// After you specify the TupleTags for each of your ParDo outputs, pass the
tags to your ParDo by invoking
+// .withOutputTags. You pass the tag for the main output first, and then the
tags for any additional outputs
+// in a TupleTagList. Building on our previous example, we pass the three
TupleTags for our three output
+// PCollections to our ParDo. Note that all of the outputs (including the main
output PCollection) are
+// bundled into the returned PCollectionTuple.
+
+ PCollectionTuple results =
+ words.apply(ParDo
+ .of(new DoFn<String, String>() {
+ // DoFn continues here.
+ ...
+ })
+ // Specify the tag for the main output.
+ .withOutputTags(wordsBelowCutOffTag,
+ // Specify the tags for the two additional outputs as a TupleTagList.
+ TupleTagList.of(wordLengthsAboveCutOffTag)
+ .and(markedWordsTag)));
+```
+
+**Example 3**: Tags for multiple outputs
+
+```java
+// Inside your ParDo's DoFn, you can emit an element to a specific output
PCollection by passing in the
+// appropriate TupleTag when you call ProcessContext.output.
+// After your ParDo, extract the resulting output PCollections from the
returned PCollectionTuple.
+// Based on the previous example, this shows the DoFn emitting to the main
output and two additional outputs.
+
+ .of(new DoFn<String, String>() {
+ public void processElement(ProcessContext c) {
+ String word = c.element();
+ if (word.length() <= wordLengthCutOff) {
+ // Emit short word to the main output.
+ // In this example, it is the output with tag wordsBelowCutOffTag.
+ c.output(word);
+ } else {
+ // Emit long word length to the output with tag
wordLengthsAboveCutOffTag.
+ c.output(wordLengthsAboveCutOffTag, word.length());
+ }
+ if (word.startsWith("MARKER")) {
+ // Emit word to the output with tag markedWordsTag.
+ c.output(markedWordsTag, word);
+ }
+ }}));
+```
+
+
+## Related transforms
+* [MapElements]({{ site.baseurl
}}/documentation/transforms/java/elementwise/mapelements)
+ applies a simple 1-to-1 mapping function over each element in the collection.
+* [Filter]({{ site.baseurl }}/documentation/transforms/java/elementwise/filter)
+ is useful if the function is just deciding whether to output an element or
not.
\ No newline at end of file
diff --git
a/website/src/documentation/transforms/java/element-wise/partition.md
b/website/src/documentation/transforms/java/element-wise/partition.md
new file mode 100644
index 0000000..583f631
--- /dev/null
+++ b/website/src/documentation/transforms/java/element-wise/partition.md
@@ -0,0 +1,62 @@
+---
+layout: section
+title: "Partition"
+permalink: /documentation/transforms/java/elementwise/partition/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# Partition
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/Partition.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Separates elements in a collection into multiple output collections. The
partitioning function contains the logic that determines how to separate the
elements of the input collection into each resulting partition output
collection.
+
+The number of partitions must be determined at graph construction time. You
cannot determine the number of partitions in mid-pipeline.
+
+See more information in the [Beam Programming Guide]({{ site.baseurl
}}/documentation/programming-guide/#partition).
+
+## Examples
+**Example**: dividing a `PCollection` into percentile groups
+
+```java
+// Provide an int value with the desired number of result partitions, and a
PartitionFn that represents the
+// partitioning function. In this example, we define the PartitionFn in-line.
Returns a PCollectionList
+// containing each of the resulting partitions as individual PCollection
objects.
+PCollection<Student> students = ...;
+// Split students up into 10 partitions, by percentile:
+PCollectionList<Student> studentsByPercentile =
+ students.apply(Partition.of(10, new PartitionFn<Student>() {
+ public int partitionFor(Student student, int numPartitions) {
+ return student.getPercentile() // 0..99
+ * numPartitions / 100;
+ }}));
+
+// You can extract each partition from the PCollectionList using the get
method, as follows:
+PCollection<Student> fortiethPercentile = studentsByPercentile.get(4);
+```
+
+## Related transforms
+* [Filter]({{ site.baseurl
}}/documentation/transforms/java/elementwise/filter) is useful if the function
is just
+ deciding whether to output an element or not.
+* [ParDo]({{ site.baseurl }}/documentation/transforms/java/elementwise/pardo)
is the most general element-wise mapping
+ operation, and includes other abilities such as multiple output collections
and side-inputs.
+* [CoGroupByKey]({{ site.baseurl
}}/documentation/transforms/java/aggregation/cogroupbykey)
+ performs a per-key equijoin.
\ No newline at end of file
diff --git a/website/src/documentation/transforms/java/element-wise/regex.md
b/website/src/documentation/transforms/java/element-wise/regex.md
new file mode 100644
index 0000000..5fff595
--- /dev/null
+++ b/website/src/documentation/transforms/java/element-wise/regex.md
@@ -0,0 +1,36 @@
+---
+layout: section
+title: "Regex"
+permalink: /documentation/transforms/java/elementwise/regex/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# Regex
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/Regex.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Provides a variety of functionality based on regular expressions.
+
+## Examples
+See [BEAM-7702](https://issues.apache.org/jira/browse/BEAM-7702) for updates.
+
+## Related transforms
+* [MapElements]({{ site.baseurl
}}/documentation/transforms/java/elementwise/mapelements)
\ No newline at end of file
diff --git a/website/src/documentation/transforms/java/element-wise/reify.md
b/website/src/documentation/transforms/java/element-wise/reify.md
new file mode 100644
index 0000000..84c3241
--- /dev/null
+++ b/website/src/documentation/transforms/java/element-wise/reify.md
@@ -0,0 +1,39 @@
+---
+layout: section
+title: "Reify"
+permalink: /documentation/transforms/java/elementwise/reify/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# Reify
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/Reify.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Transforms for converting between explicit and implicit form of various Beam
values.
+
+## Examples
+See [BEAM-7702](https://issues.apache.org/jira/browse/BEAM-7702) for updates.
+
+## Related transforms
+* [WithTimestamps]({{ site.baseurl
}}/documentation/transforms/java/elementwise/withtimestamps)
+ assigns timestamps to all the elements of a collection
+* [Window]({{ site.baseurl }}/documentation/transforms/java/other/window/)
divides up or
+ groups the elements of a collection into finite windows
diff --git a/website/src/documentation/transforms/java/element-wise/tostring.md
b/website/src/documentation/transforms/java/element-wise/tostring.md
new file mode 100644
index 0000000..dde6ac0
--- /dev/null
+++ b/website/src/documentation/transforms/java/element-wise/tostring.md
@@ -0,0 +1,37 @@
+---
+layout: section
+title: "ToString"
+permalink: /documentation/transforms/java/elementwise/tostring/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# ToString
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/ToString.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+A variety of utility transforms for invoking the `toString()` method
+on every element in the input collection.
+
+## Examples
+See [BEAM-7702](https://issues.apache.org/jira/browse/BEAM-7702) for updates.
+
+## Related transforms
+* [MapElements]({{ site.baseurl
}}/documentation/transforms/java/elementwise/mapelements)
\ No newline at end of file
diff --git a/website/src/documentation/transforms/java/element-wise/values.md
b/website/src/documentation/transforms/java/element-wise/values.md
new file mode 100644
index 0000000..b810db4
--- /dev/null
+++ b/website/src/documentation/transforms/java/element-wise/values.md
@@ -0,0 +1,44 @@
+---
+layout: section
+title: "Values"
+permalink: /documentation/transforms/java/elementwise/values/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# Values
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/Values.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+The `Values` transform takes a collection of key-value pairs, and
+returns the value of each element.
+
+## Examples
+**Example**
+
+```java
+PCollection<KV<String, Integer>> keyValuePairs = /* ... */;
+PCollection<Integer> values = keyValuePairs.apply(Values.create());
+```
+
+## Related transforms
+* [Keys]({{ site.baseurl }}/documentation/transforms/java/elementwise/keys)
for extracting the key of each component.
+* [KvSwap]({{ site.baseurl
}}/documentation/transforms/java/elementwise/kvswap) swaps key-value pair
values.
+* [WithKeys]({{ site.baseurl
}}/documentation/transforms/java/elementwise/withkeys) for adding a key to each
element.
diff --git a/website/src/documentation/transforms/java/element-wise/withkeys.md
b/website/src/documentation/transforms/java/element-wise/withkeys.md
new file mode 100644
index 0000000..6c6df43
--- /dev/null
+++ b/website/src/documentation/transforms/java/element-wise/withkeys.md
@@ -0,0 +1,55 @@
+---
+layout: section
+title: "WithKeys"
+permalink: /documentation/transforms/java/elementwise/withkeys/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# WithKeys
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/WithKeys.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Takes a `PCollection<V>` and produces a `PCollection<KV<K, V>>` by associating
+each input element with a key.
+
+There are two versions of `WithKeys`, depending on how the key should be
determined:
+
+* `WithKeys.of(SerializableFunction<V, K> fn)` takes a function to
+ compute the key from each value.
+* `WithKeys.of(K key)` associates each value with the specified key.
+
+## Examples
+**Example**
+```java
+PCollection<String> words = Create.of("Hello", "World", "Beam", "is", "fun");
+PCollection<KV<Integer, String>> lengthAndWord =
+ words.apply(WithKeys.of(new SerialiazableFunction<String, Integer>() {
+ @Override
+ public Integer apply(String s) {
+ return s.length();
+ }
+ });
+```
+
+## Related transforms
+* [Keys]({{ site.baseurl }}/documentation/transforms/java/elementwise/keys)
for extracting the key of each component.
+* [Values]({{ site.baseurl
}}/documentation/transforms/java/elementwise/values) for extracting the value
of each element.
+* [KvSwap]({{ site.baseurl
}}/documentation/transforms/java/elementwise/kvswap) swaps key-value pair
values.
\ No newline at end of file
diff --git
a/website/src/documentation/transforms/java/element-wise/withtimestamps.md
b/website/src/documentation/transforms/java/element-wise/withtimestamps.md
new file mode 100644
index 0000000..a2f7e41
--- /dev/null
+++ b/website/src/documentation/transforms/java/element-wise/withtimestamps.md
@@ -0,0 +1,36 @@
+---
+layout: section
+title: "WithTimestamps"
+permalink: /documentation/transforms/java/elementwise/withtimestamps/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# WithTimestamps
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/WithTimestamps.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Assigns timestamps to all the elements of a collection.
+
+## Examples
+See [BEAM-7702](https://issues.apache.org/jira/browse/BEAM-7702) for updates.
+
+## Related transforms
+* [Reify]({{ site.baseurl }}/documentation/transforms/java/elementwise/reify)
\ No newline at end of file
diff --git a/website/src/documentation/transforms/java/index.md
b/website/src/documentation/transforms/java/index.md
new file mode 100644
index 0000000..b36e305
--- /dev/null
+++ b/website/src/documentation/transforms/java/index.md
@@ -0,0 +1,81 @@
+---
+layout: section
+title: "Java transform catalog overview"
+permalink: /documentation/transforms/java/overview/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+
+# Java transform catalog overview
+
+## Element-wise
+
+<table class="table-bordered table-striped">
+ <tr><th>Transform</th><th>Description</th></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/elementwise/filter">Filter</a></td><td>Given a
predicate, filter out all elements that don't satisfy the predicate.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/elementwise/flatmapelements">FlatMapElements</a></td><td>Applies
a function that returns a collection to every element in the input and
+ outputs all resulting elements.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/elementwise/keys">Keys</a></td><td>Extracts
the key from each element in a collection of key-value pairs.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/elementwise/kvswap">KvSwap</a></td><td>Swaps
the key and value of each element in a collection of key-value pairs.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/elementwise/mapelements">MapElements</a></td><td>Applies
a function to every element in the input and outputs the result.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/elementwise/pardo">ParDo</a></td><td>The
most-general mechanism for applying a user-defined <code>DoFn</code> to every
element
+ in the input collection.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/elementwise/partition">Partition</a></td><td>Routes
each input element to a specific output collection based on some partition
+ function.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/elementwise/regex">Regex</a></td><td>Filters
input string elements based on a regex. May also transform them based on the
matching groups.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/elementwise/reify">Reify</a></td><td>Transforms
for converting between explicit and implicit form of various Beam
values.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/elementwise/tostring">ToString</a></td><td>Transforms
every element in an input collection to a string.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/elementwise/withkeys">WithKeys</a></td><td>Produces
a collection containing each element from the input collection converted to a
key-value pair, with a key selected by applying a function to the input
element.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/elementwise/withtimestamps">WithTimestamps</a></td><td>Applies
a function to determine a timestamp to each element in the output collection,
+ and updates the implicit timestamp associated with each input. Note that it
is only safe to adjust timestamps forwards.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/elementwise/values">Values</a></td><td>Extracts
the value from each element in a collection of key-value pairs.</td></tr>
+</table>
+
+
+
+## Aggregation
+<table class="table-bordered table-striped">
+ <tr><th>Transform</th><th>Description</th></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/approximatequantiles">ApproximateQuantiles</a></td><td>Uses
an approximation algorithm to estimate the data distribution within each
aggregation using a specified number of quantiles.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/approximateunique">ApproximateUnique</a></td><td>Uses
an approximation algorithm to estimate the number of unique elements within
each aggregation.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/cogroupbykey/">CoGroupByKey</a></td><td>Similar
to <code>GroupByKey</code>, but groups values associated with each key into a
batch of a given size</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/combine">Combine</a></td><td>Transforms
to combine elements according to a provided <code>CombineFn</code>.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/combinewithcontext">CombineWithContext</a></td><td>An
extended version of Combine which allows accessing side-inputs and other
context.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/count">Count</a></td><td>Counts
the number of elements within each aggregation.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/distinct">Distinct</a></td><td>Produces
a collection containing distinct elements from the input collection.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/groupbykey">GroupByKey</a></td><td>Takes
a keyed collection of elements and produces a collection where each element
+ consists of a key and all values associated with that key.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/groupintobatches">GroupIntoBatches</a></td><td>Batches
values associated with keys into <code>Iterable</code> batches of some size.
Each batch contains elements associated with a specific key.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/latest">Latest</a></td><td>Selects
the latest element within each aggregation according to the implicit
timestamp.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/max">Max</a></td><td>Outputs the
maximum element within each aggregation.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/mean">Mean</a></td><td>Computes
the average within each aggregation.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/min">Min</a></td><td>Outputs the
minimum element within each aggregation.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/sample">Sample</a></td><td>Randomly
select some number of elements from each aggregation.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/sum">Sum</a></td><td>Compute the
sum of elements in each aggregation.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/aggregation/top">Top</a></td><td>Compute the
largest element(s) in each aggregation.</td></tr>
+</table>
+
+
+## Other
+<table class="table-bordered table-striped">
+ <tr><th>Transform</th><th>Description</th></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/other/create">Create</a></td><td>Creates a
collection from an in-memory list.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/other/flatten">Flatten</a></td><td>Given
multiple input collections, produces a single output collection containing
+ all elements from all of the input collections.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/other/passert">PAssert</a></td><td>A transform
to assert the contents of a <code>PCollection</code> used as part of testing a
pipeline either locally or with a runner.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/other/view">View</a></td><td>Operations for
turning a collection into view that may be used as a side-input to a
<code>ParDo</code>.</td></tr>
+ <tr><td><a href="{{ site.baseurl
}}/documentation/transforms/java/other/window">Window</a></td><td>Logically
divides up or groups the elements of a collection into finite
+ windows according to a provided <code>WindowFn</code>.</td></tr>
+</table>
\ No newline at end of file
diff --git a/website/src/documentation/transforms/java/other/create.md
b/website/src/documentation/transforms/java/other/create.md
new file mode 100644
index 0000000..d81607b
--- /dev/null
+++ b/website/src/documentation/transforms/java/other/create.md
@@ -0,0 +1,40 @@
+---
+layout: section
+title: "Create"
+permalink: /documentation/transforms/java/other/create/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# Create
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/Create.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Creates a collection containing a specified set of elements. This is useful
+for testing, as well as creating an initial input to process in parallel.
+For example, a single element to execute a one-time `ParDo` or a list of
filenames to be read.
+
+
+## Examples
+
+See [BEAM-7704](https://issues.apache.org/jira/browse/BEAM-7704) for updates.
+
+## Related transforms
+N/A
diff --git a/website/src/documentation/transforms/java/other/flatten.md
b/website/src/documentation/transforms/java/other/flatten.md
new file mode 100644
index 0000000..c8c22aa
--- /dev/null
+++ b/website/src/documentation/transforms/java/other/flatten.md
@@ -0,0 +1,67 @@
+---
+layout: section
+title: "Flatten"
+permalink: /documentation/transforms/java/other/flatten/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# Flatten
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/Flatten.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Merges multiple `PCollection` objects into a single logical `PCollection`.
+
+By default, the coder for the output `PCollection` is the same as the coder
+for the first `PCollection` in the input `PCollectionList`. However, the
+input `PCollection` objects can each use different coders, as long as
+they all contain the same data type in your chosen language.
+
+When using `Flatten` to merge `PCollection` objects that have a windowing
+strategy applied, all of the `PCollection` objects you want to merge must
+use a compatible windowing strategy and window sizing. For example, all
+the collections you're merging must all use (hypothetically) identical
+5-minute fixed windows or 4-minute sliding windows starting every 30 seconds.
+
+If your pipeline attempts to use `Flatten` to merge `PCollection` objects
+with incompatible windows, Beam generates an `IllegalStateException` error
+when your pipeline is constructed
+
+See more information in the [Beam Programming Guide]({{ site.baseurl
}}/documentation/programming-guide/#flatten).
+
+## Examples
+**Example**: Apply a `Flatten` transform to merge multiple `PCollection`
objects
+
+```java
+// Flatten takes a PCollectionList of PCollection objects of a given type.
+// Returns a single PCollection that contains all of the elements in the
PCollection objects in that list.
+PCollection<String> pc1 = Create.of("Hello");
+PCollection<String> pc2 = Create.of("World", "Beam");
+PCollection<String> pc3 = Create.of("Is", "Fun");
+PCollectionList<String> collections =
PCollectionList.of(pc1).and(pc2).and(pc3);
+
+PCollection<String> merged = collections.apply(Flatten.<String>pCollections());
+```
+The resulting collection now has all the elements: "Hello", "World",
+"Beam", "Is", and "Fun".
+
+## Related transforms
+* [ParDo]({{ site.baseurl }}/documentation/transforms/java/elementwise/pardo)
+* [Partition]({{ site.baseurl
}}/documentation/transforms/java/elementwise/partition)
\ No newline at end of file
diff --git a/website/src/documentation/transforms/java/other/passert.md
b/website/src/documentation/transforms/java/other/passert.md
new file mode 100644
index 0000000..85d4201
--- /dev/null
+++ b/website/src/documentation/transforms/java/other/passert.md
@@ -0,0 +1,61 @@
+---
+layout: section
+title: "PAssert"
+permalink: /documentation/transforms/java/other/passert/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# PAssert
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/PAssert.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+`PAssert` is a class included in the Beam Java SDK that is an
+assertion on the contents of a `PCollection`. You can use `PAssert` to verify
+that a `PCollection` contains a specific set of expected elements.
+
+## Examples
+For a given `PCollection`, you can use `PAssert` to verify the contents as
follows:
+```java
+PCollection<String> output = ...;
+
+// Check whether a PCollection contains some elements in any order.
+PAssert.that(output)
+.containsInAnyOrder(
+ "elem1",
+ "elem3",
+ "elem2");
+```
+
+Any code that uses `PAssert` must link in `JUnit` and `Hamcrest`.
+If you're using Maven, you can link in `Hamcrest` by adding the
+following dependency to your project's pom.xml file:
+
+```java
+<dependency>
+ <groupId>org.hamcrest</groupId>
+ <artifactId>hamcrest-all</artifactId>
+ <version>1.3</version>
+ <scope>test</scope>
+</dependency>
+```
+
+## Related transforms
+* TestStream
\ No newline at end of file
diff --git a/website/src/documentation/transforms/java/other/view.md
b/website/src/documentation/transforms/java/other/view.md
new file mode 100644
index 0000000..fe30b99
--- /dev/null
+++ b/website/src/documentation/transforms/java/other/view.md
@@ -0,0 +1,37 @@
+---
+layout: section
+title: "View"
+permalink: /documentation/transforms/java/other/view/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# View
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/2.13.0/index.html?org/apache/beam/sdk/transforms/View.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Operations for turning a collection into view that may be used as a side-input
to a `ParDo`.
+
+## Examples
+See [BEAM-7704](https://issues.apache.org/jira/browse/BEAM-7704) for updates.
+
+## Related transforms
+* [ParDo]({{ site.baseurl }}/documentation/transforms/java/elementwise/pardo)
+* [CombineWithContext]({{ site.baseurl
}}/documentation/transforms/java/aggregation/combinewithcontext)
diff --git a/website/src/documentation/transforms/java/other/window.md
b/website/src/documentation/transforms/java/other/window.md
new file mode 100644
index 0000000..038f18c
--- /dev/null
+++ b/website/src/documentation/transforms/java/other/window.md
@@ -0,0 +1,40 @@
+---
+layout: section
+title: "Window"
+permalink: /documentation/transforms/java/other/window/
+section_menu: section-menu/documentation.html
+---
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+# Window
+<table align="left">
+ <a target="_blank" class="button"
+
href="https://beam.apache.org/releases/javadoc/current/index.html?org/apache/beam/sdk/transforms/windowing/Window.html";>
+ <img src="https://beam.apache.org/images/logos/sdks/java.png";
width="20px" height="20px"
+ alt="Javadoc" />
+ Javadoc
+ </a>
+</table>
+<br>
+Logically divides up or groups the elements of a collection into finite
+windows according to a function.
+
+## Examples
+See [BEAM-7704](https://issues.apache.org/jira/browse/BEAM-7704) for updates.
+
+## Related transforms
+* [Reify]({{ site.baseurl }}/documentation/transforms/java/elementwise/reify)
+ converts between explicit and implicit form of various Beam values.
+* [WithTimestamps]({{ site.baseurl
}}/documentation/transforms/java/elementwise/withtimestamps)
+ applies a function to determine a timestamp to each element in the output
collection.
\ No newline at end of file
![https://beam.apache.org/images/logos/sdks/java.png"](https://beam.apache.org/images/logos/sdks/java.png"){kind=link}