klion26 commented on a change in pull request #13225:
URL: https://github.com/apache/flink/pull/13225#discussion_r478844519
##########
File path: docs/dev/user_defined_functions.zh.md
##########
@@ -147,95 +153,77 @@ data.map (new RichMapFunction[String, Int] {
</div>
-Rich functions provide, in addition to the user-defined function (map,
-reduce, etc), four methods: `open`, `close`, `getRuntimeContext`, and
-`setRuntimeContext`. These are useful for parameterizing the function
-(see [Passing Parameters to Functions]({{ site.baseurl
}}/dev/batch/index.html#passing-parameters-to-functions)),
-creating and finalizing local state, accessing broadcast variables (see
-[Broadcast Variables]({{ site.baseurl
}}/dev/batch/index.html#broadcast-variables)), and for accessing runtime
-information such as accumulators and counters (see
-[Accumulators and Counters](#accumulators--counters)), and information
-on iterations (see [Iterations]({{ site.baseurl }}/dev/batch/iterations.html)).
+除了用户自定义的功能（map，reduce 等），Rich functions
还提供了四个方法：`open`、`close`、`getRuntimeContext` 和
+`setRuntimeContext`。这些对于参数化功能很有用
+(参阅 [给函数传递参数]({{ site.baseurl
}}/zh/dev/batch/index.html#passing-parameters-to-functions))，
+创建和最终确定本地状态，访问广播变量(参阅
+[广播变量]({{ site.baseurl
}}/zh/dev/batch/index.html#broadcast-variables))，以及访问运行时信息，例如累加器和计数器(参阅
+[累加器和计数器](#累加器和计数器))，以及迭代器的相关信息(参阅 [迭代器]({{ site.baseurl
}}/zh/dev/batch/iterations.html))。
{% top %}
-## Accumulators & Counters
+<a name="accumulators--counters"></a>
-Accumulators are simple constructs with an **add operation** and a **final
accumulated result**,
-which is available after the job ended.
+## 累加器和计数器
-The most straightforward accumulator is a **counter**: You can increment it
using the
-```Accumulator.add(V value)``` method. At the end of the job Flink will sum up
(merge) all partial
-results and send the result to the client. Accumulators are useful during
debugging or if you
-quickly want to find out more about your data.
+累加器是具有**加法运算**和**最终累加结果**的一种简单结构，可在作业结束后使用。
-Flink currently has the following **built-in accumulators**. Each of them
implements the
-{% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/Accumulator.java
"Accumulator" %}
-interface.
+最简单的累加器就是**计数器**: 你可以使用
+```Accumulator.add(V value)``` 方法将其递增。在作业结束时，Flink 会汇总(合并)所有部分的结果并将其发送给客户端。
+在调试过程中或在你想快速了解有关数据更多信息时,累加器作用很大。
+
+Flink 目前有如下**内置累加器**。每个都实现了
+{% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/Accumulator.java
"累加器" %}
+接口。
- {% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/IntCounter.java
"__IntCounter__" %},
{% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/LongCounter.java
"__LongCounter__" %}
- and {% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/DoubleCounter.java
"__DoubleCounter__" %}:
- See below for an example using a counter.
-- {% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/Histogram.java
"__Histogram__" %}:
- A histogram implementation for a discrete number of bins. Internally it is
just a map from Integer
- to Integer. You can use this to compute distributions of values, e.g. the
distribution of
- words-per-line for a word count program.
+ 和 {% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/DoubleCounter.java
"__DoubleCounter__" %}:
+ 有关使用计数器的示例，请参见下文。
+- {% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/Histogram.java
"__直方图__" %}:
+ 离散数量的柱状直方图实现。在内部，它只是整形到整形的映射。你可以使用它来计算值的分布，例如，单词计数程序的每行单词的分布情况。
-__How to use accumulators:__
+__如何使用累加器：__
-First you have to create an accumulator object (here a counter) in the
user-defined transformation
-function where you want to use it.
+首先，你要在需要使用累加器的用户自定义的转换函数中创建一个累加器对象（此处是计数器）。
Review comment:
```suggestion
首先，在需要使用累加器的用户自定义函数中创建一个累加器对象（此处是计数器）。
```
##########
File path: docs/dev/user_defined_functions.zh.md
##########
@@ -147,95 +153,77 @@ data.map (new RichMapFunction[String, Int] {
</div>
-Rich functions provide, in addition to the user-defined function (map,
-reduce, etc), four methods: `open`, `close`, `getRuntimeContext`, and
-`setRuntimeContext`. These are useful for parameterizing the function
-(see [Passing Parameters to Functions]({{ site.baseurl
}}/dev/batch/index.html#passing-parameters-to-functions)),
-creating and finalizing local state, accessing broadcast variables (see
-[Broadcast Variables]({{ site.baseurl
}}/dev/batch/index.html#broadcast-variables)), and for accessing runtime
-information such as accumulators and counters (see
-[Accumulators and Counters](#accumulators--counters)), and information
-on iterations (see [Iterations]({{ site.baseurl }}/dev/batch/iterations.html)).
+除了用户自定义的功能（map，reduce 等），Rich functions
还提供了四个方法：`open`、`close`、`getRuntimeContext` 和
+`setRuntimeContext`。这些对于参数化功能很有用
+(参阅 [给函数传递参数]({{ site.baseurl
}}/zh/dev/batch/index.html#passing-parameters-to-functions))，
Review comment:
像 @RocMarshal 说的一样，现在的链接，建议使用 `{%link %}` 的形式，具体原因可以看他给出的链接
##########
File path: docs/dev/user_defined_functions.zh.md
##########
@@ -147,95 +153,77 @@ data.map (new RichMapFunction[String, Int] {
</div>
-Rich functions provide, in addition to the user-defined function (map,
-reduce, etc), four methods: `open`, `close`, `getRuntimeContext`, and
-`setRuntimeContext`. These are useful for parameterizing the function
-(see [Passing Parameters to Functions]({{ site.baseurl
}}/dev/batch/index.html#passing-parameters-to-functions)),
-creating and finalizing local state, accessing broadcast variables (see
-[Broadcast Variables]({{ site.baseurl
}}/dev/batch/index.html#broadcast-variables)), and for accessing runtime
-information such as accumulators and counters (see
-[Accumulators and Counters](#accumulators--counters)), and information
-on iterations (see [Iterations]({{ site.baseurl }}/dev/batch/iterations.html)).
+除了用户自定义的功能（map，reduce 等），Rich functions
还提供了四个方法：`open`、`close`、`getRuntimeContext` 和
+`setRuntimeContext`。这些对于参数化功能很有用
Review comment:
`这些对于参数化功能很有用` 这个单纯读中文觉得有点奇怪，能否优化一下呢？
##########
File path: docs/dev/user_defined_functions.zh.md
##########
@@ -147,95 +153,77 @@ data.map (new RichMapFunction[String, Int] {
</div>
-Rich functions provide, in addition to the user-defined function (map,
-reduce, etc), four methods: `open`, `close`, `getRuntimeContext`, and
-`setRuntimeContext`. These are useful for parameterizing the function
-(see [Passing Parameters to Functions]({{ site.baseurl
}}/dev/batch/index.html#passing-parameters-to-functions)),
-creating and finalizing local state, accessing broadcast variables (see
-[Broadcast Variables]({{ site.baseurl
}}/dev/batch/index.html#broadcast-variables)), and for accessing runtime
-information such as accumulators and counters (see
-[Accumulators and Counters](#accumulators--counters)), and information
-on iterations (see [Iterations]({{ site.baseurl }}/dev/batch/iterations.html)).
+除了用户自定义的功能（map，reduce 等），Rich functions
还提供了四个方法：`open`、`close`、`getRuntimeContext` 和
+`setRuntimeContext`。这些对于参数化功能很有用
+(参阅 [给函数传递参数]({{ site.baseurl
}}/zh/dev/batch/index.html#passing-parameters-to-functions))，
+创建和最终确定本地状态，访问广播变量(参阅
+[广播变量]({{ site.baseurl
}}/zh/dev/batch/index.html#broadcast-variables))，以及访问运行时信息，例如累加器和计数器(参阅
+[累加器和计数器](#累加器和计数器))，以及迭代器的相关信息(参阅 [迭代器]({{ site.baseurl
}}/zh/dev/batch/iterations.html))。
{% top %}
-## Accumulators & Counters
+<a name="accumulators--counters"></a>
-Accumulators are simple constructs with an **add operation** and a **final
accumulated result**,
-which is available after the job ended.
+## 累加器和计数器
-The most straightforward accumulator is a **counter**: You can increment it
using the
-```Accumulator.add(V value)``` method. At the end of the job Flink will sum up
(merge) all partial
-results and send the result to the client. Accumulators are useful during
debugging or if you
-quickly want to find out more about your data.
+累加器是具有**加法运算**和**最终累加结果**的一种简单结构，可在作业结束后使用。
-Flink currently has the following **built-in accumulators**. Each of them
implements the
-{% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/Accumulator.java
"Accumulator" %}
-interface.
+最简单的累加器就是**计数器**: 你可以使用
+```Accumulator.add(V value)``` 方法将其递增。在作业结束时，Flink 会汇总(合并)所有部分的结果并将其发送给客户端。
+在调试过程中或在你想快速了解有关数据更多信息时,累加器作用很大。
+
+Flink 目前有如下**内置累加器**。每个都实现了
+{% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/Accumulator.java
"累加器" %}
+接口。
- {% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/IntCounter.java
"__IntCounter__" %},
{% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/LongCounter.java
"__LongCounter__" %}
- and {% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/DoubleCounter.java
"__DoubleCounter__" %}:
- See below for an example using a counter.
-- {% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/Histogram.java
"__Histogram__" %}:
- A histogram implementation for a discrete number of bins. Internally it is
just a map from Integer
- to Integer. You can use this to compute distributions of values, e.g. the
distribution of
- words-per-line for a word count program.
+ 和 {% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/DoubleCounter.java
"__DoubleCounter__" %}:
+ 有关使用计数器的示例，请参见下文。
+- {% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/Histogram.java
"__直方图__" %}:
+ 离散数量的柱状直方图实现。在内部，它只是整形到整形的映射。你可以使用它来计算值的分布，例如，单词计数程序的每行单词的分布情况。
-__How to use accumulators:__
+__如何使用累加器：__
-First you have to create an accumulator object (here a counter) in the
user-defined transformation
-function where you want to use it.
+首先，你要在需要使用累加器的用户自定义的转换函数中创建一个累加器对象（此处是计数器）。
{% highlight java %}
private IntCounter numLines = new IntCounter();
{% endhighlight %}
-Second you have to register the accumulator object, typically in the
```open()``` method of the
-*rich* function. Here you also define the name.
+其次，你必须在富函数的```open()```方法中注册累加器对象。也可以在此处定义名称。
{% highlight java %}
getRuntimeContext().addAccumulator("num-lines", this.numLines);
{% endhighlight %}
-You can now use the accumulator anywhere in the operator function, including
in the ```open()``` and
-```close()``` methods.
+现在你可以在操作函数中的任何位置（包括 ```open()``` 和 ```close()``` 方法中）使用累加器。
{% highlight java %}
this.numLines.add(1);
{% endhighlight %}
-The overall result will be stored in the ```JobExecutionResult``` object which
is
-returned from the `execute()` method of the execution environment
-(currently this only works if the execution waits for the
-completion of the job).
+最终整体结果会存储在由执行环境的 `execute()` 方法返回的 ```JobExecutionResult```
对象中（当前只有等待作业完成后执行才起作用）。
{% highlight java %}
myJobExecutionResult.getAccumulatorResult("num-lines")
{% endhighlight %}
-All accumulators share a single namespace per job. Thus you can use the same
accumulator in
-different operator functions of your job. Flink will internally merge all
accumulators with the same
-name.
+单个作业的所有累加器共享一个命名空间。因此你可以在不同的操作函数里面使用同一个累加器。Flink 会在内部将所有具有相同名称的累加器合并起来。
-A note on accumulators and iterations: Currently the result of accumulators is
only available after
-the overall job has ended. We plan to also make the result of the previous
iteration available in the
-next iteration. You can use
-{% gh_link
/flink-java/src/main/java/org/apache/flink/api/java/operators/IterativeDataSet.java#L98
"Aggregators" %}
-to compute per-iteration statistics and base the termination of iterations on
such statistics.
+关于累加器和迭代的注意事项：当前累加器的结果只有在整个作业结束后才可用。我们还计划在下一次迭代中提供上一次的迭代结果。你可以使用
+{% gh_link
/flink-java/src/main/java/org/apache/flink/api/java/operators/IterativeDataSet.java#L98
"聚合器" %}
+来计算每次迭代的统计信息，并基于此类统计信息来终止迭代。
-__Custom accumulators:__
+__定制累加器：__
-To implement your own accumulator you simply have to write your implementation
of the Accumulator
-interface. Feel free to create a pull request if you think your custom
accumulator should be shipped
-with Flink.
+要实现自己的累加器，你只需要实现累加器接口即可。如果你认为自定义累加器应随 Flink 一起提供，请尽管创建拉取请求。
Review comment:
`拉取请求` 我个人建议保持 `pull request` 原文，中文不一定知道是什么意思
##########
File path: docs/dev/user_defined_functions.zh.md
##########
@@ -147,95 +153,77 @@ data.map (new RichMapFunction[String, Int] {
</div>
-Rich functions provide, in addition to the user-defined function (map,
-reduce, etc), four methods: `open`, `close`, `getRuntimeContext`, and
-`setRuntimeContext`. These are useful for parameterizing the function
-(see [Passing Parameters to Functions]({{ site.baseurl
}}/dev/batch/index.html#passing-parameters-to-functions)),
-creating and finalizing local state, accessing broadcast variables (see
-[Broadcast Variables]({{ site.baseurl
}}/dev/batch/index.html#broadcast-variables)), and for accessing runtime
-information such as accumulators and counters (see
-[Accumulators and Counters](#accumulators--counters)), and information
-on iterations (see [Iterations]({{ site.baseurl }}/dev/batch/iterations.html)).
+除了用户自定义的功能（map，reduce 等），Rich functions
还提供了四个方法：`open`、`close`、`getRuntimeContext` 和
+`setRuntimeContext`。这些对于参数化功能很有用
+(参阅 [给函数传递参数]({{ site.baseurl
}}/zh/dev/batch/index.html#passing-parameters-to-functions))，
+创建和最终确定本地状态，访问广播变量(参阅
+[广播变量]({{ site.baseurl
}}/zh/dev/batch/index.html#broadcast-variables))，以及访问运行时信息，例如累加器和计数器(参阅
+[累加器和计数器](#累加器和计数器))，以及迭代器的相关信息(参阅 [迭代器]({{ site.baseurl
}}/zh/dev/batch/iterations.html))。
{% top %}
-## Accumulators & Counters
+<a name="accumulators--counters"></a>
-Accumulators are simple constructs with an **add operation** and a **final
accumulated result**,
-which is available after the job ended.
+## 累加器和计数器
-The most straightforward accumulator is a **counter**: You can increment it
using the
-```Accumulator.add(V value)``` method. At the end of the job Flink will sum up
(merge) all partial
-results and send the result to the client. Accumulators are useful during
debugging or if you
-quickly want to find out more about your data.
+累加器是具有**加法运算**和**最终累加结果**的一种简单结构，可在作业结束后使用。
-Flink currently has the following **built-in accumulators**. Each of them
implements the
-{% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/Accumulator.java
"Accumulator" %}
-interface.
+最简单的累加器就是**计数器**: 你可以使用
+```Accumulator.add(V value)``` 方法将其递增。在作业结束时，Flink 会汇总(合并)所有部分的结果并将其发送给客户端。
+在调试过程中或在你想快速了解有关数据更多信息时,累加器作用很大。
+
+Flink 目前有如下**内置累加器**。每个都实现了
+{% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/Accumulator.java
"累加器" %}
+接口。
- {% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/IntCounter.java
"__IntCounter__" %},
{% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/LongCounter.java
"__LongCounter__" %}
- and {% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/DoubleCounter.java
"__DoubleCounter__" %}:
- See below for an example using a counter.
-- {% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/Histogram.java
"__Histogram__" %}:
- A histogram implementation for a discrete number of bins. Internally it is
just a map from Integer
- to Integer. You can use this to compute distributions of values, e.g. the
distribution of
- words-per-line for a word count program.
+ 和 {% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/DoubleCounter.java
"__DoubleCounter__" %}:
+ 有关使用计数器的示例，请参见下文。
+- {% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/Histogram.java
"__直方图__" %}:
+ 离散数量的柱状直方图实现。在内部，它只是整形到整形的映射。你可以使用它来计算值的分布，例如，单词计数程序的每行单词的分布情况。
-__How to use accumulators:__
+__如何使用累加器：__
-First you have to create an accumulator object (here a counter) in the
user-defined transformation
-function where you want to use it.
+首先，你要在需要使用累加器的用户自定义的转换函数中创建一个累加器对象（此处是计数器）。
{% highlight java %}
private IntCounter numLines = new IntCounter();
{% endhighlight %}
-Second you have to register the accumulator object, typically in the
```open()``` method of the
-*rich* function. Here you also define the name.
+其次，你必须在富函数的```open()```方法中注册累加器对象。也可以在此处定义名称。
{% highlight java %}
getRuntimeContext().addAccumulator("num-lines", this.numLines);
{% endhighlight %}
-You can now use the accumulator anywhere in the operator function, including
in the ```open()``` and
-```close()``` methods.
+现在你可以在操作函数中的任何位置（包括 ```open()``` 和 ```close()``` 方法中）使用累加器。
{% highlight java %}
this.numLines.add(1);
{% endhighlight %}
-The overall result will be stored in the ```JobExecutionResult``` object which
is
-returned from the `execute()` method of the execution environment
-(currently this only works if the execution waits for the
-completion of the job).
+最终整体结果会存储在由执行环境的 `execute()` 方法返回的 ```JobExecutionResult```
对象中（当前只有等待作业完成后执行才起作用）。
{% highlight java %}
myJobExecutionResult.getAccumulatorResult("num-lines")
{% endhighlight %}
-All accumulators share a single namespace per job. Thus you can use the same
accumulator in
-different operator functions of your job. Flink will internally merge all
accumulators with the same
-name.
+单个作业的所有累加器共享一个命名空间。因此你可以在不同的操作函数里面使用同一个累加器。Flink 会在内部将所有具有相同名称的累加器合并起来。
-A note on accumulators and iterations: Currently the result of accumulators is
only available after
-the overall job has ended. We plan to also make the result of the previous
iteration available in the
-next iteration. You can use
-{% gh_link
/flink-java/src/main/java/org/apache/flink/api/java/operators/IterativeDataSet.java#L98
"Aggregators" %}
-to compute per-iteration statistics and base the termination of iterations on
such statistics.
+关于累加器和迭代的注意事项：当前累加器的结果只有在整个作业结束后才可用。我们还计划在下一次迭代中提供上一次的迭代结果。你可以使用
+{% gh_link
/flink-java/src/main/java/org/apache/flink/api/java/operators/IterativeDataSet.java#L98
"聚合器" %}
+来计算每次迭代的统计信息，并基于此类统计信息来终止迭代。
-__Custom accumulators:__
+__定制累加器：__
-To implement your own accumulator you simply have to write your implementation
of the Accumulator
-interface. Feel free to create a pull request if you think your custom
accumulator should be shipped
-with Flink.
+要实现自己的累加器，你只需要实现累加器接口即可。如果你认为自定义累加器应随 Flink 一起提供，请尽管创建拉取请求。
-You have the choice to implement either
+你可以选择实现
{% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/Accumulator.java
"Accumulator" %}
-or {% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/SimpleAccumulator.java
"SimpleAccumulator" %}.
+或 {% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/SimpleAccumulator.java
"SimpleAccumulator" %}。
-```Accumulator<V,R>``` is most flexible: It defines a type ```V``` for the
value to add, and a
-result type ```R``` for the final result. E.g. for a histogram, ```V``` is a
number and ```R``` is
- a histogram. ```SimpleAccumulator``` is for the cases where both types are
the same, e.g. for counters.
+```Accumulator<V,R>``` 最灵活:
它给需要添加的值定义了类型```V```，并定义了最终的结果类型```R```。例如，对于直方图，```V```是一个数字且```R```是一个直方图。
Review comment:
```suggestion
```Accumulator<V,R>``` 最灵活: 它给需要添加的值定义了类型 ```V```，并定义了最终的结果类型
```R```。例如，对于直方图，```V``` 是一个数字且 ```R```是一个直方图。
```
##########
File path: docs/dev/user_defined_functions.zh.md
##########
@@ -147,95 +153,77 @@ data.map (new RichMapFunction[String, Int] {
</div>
-Rich functions provide, in addition to the user-defined function (map,
-reduce, etc), four methods: `open`, `close`, `getRuntimeContext`, and
-`setRuntimeContext`. These are useful for parameterizing the function
-(see [Passing Parameters to Functions]({{ site.baseurl
}}/dev/batch/index.html#passing-parameters-to-functions)),
-creating and finalizing local state, accessing broadcast variables (see
-[Broadcast Variables]({{ site.baseurl
}}/dev/batch/index.html#broadcast-variables)), and for accessing runtime
-information such as accumulators and counters (see
-[Accumulators and Counters](#accumulators--counters)), and information
-on iterations (see [Iterations]({{ site.baseurl }}/dev/batch/iterations.html)).
+除了用户自定义的功能（map，reduce 等），Rich functions
还提供了四个方法：`open`、`close`、`getRuntimeContext` 和
+`setRuntimeContext`。这些对于参数化功能很有用
+(参阅 [给函数传递参数]({{ site.baseurl
}}/zh/dev/batch/index.html#passing-parameters-to-functions))，
+创建和最终确定本地状态，访问广播变量(参阅
+[广播变量]({{ site.baseurl
}}/zh/dev/batch/index.html#broadcast-variables))，以及访问运行时信息，例如累加器和计数器(参阅
+[累加器和计数器](#累加器和计数器))，以及迭代器的相关信息(参阅 [迭代器]({{ site.baseurl
}}/zh/dev/batch/iterations.html))。
Review comment:
`[累加器和计数器](#累加器和计数器)` 这里的跳转不要用中文
##########
File path: docs/dev/user_defined_functions.zh.md
##########
@@ -147,95 +153,77 @@ data.map (new RichMapFunction[String, Int] {
</div>
-Rich functions provide, in addition to the user-defined function (map,
-reduce, etc), four methods: `open`, `close`, `getRuntimeContext`, and
-`setRuntimeContext`. These are useful for parameterizing the function
-(see [Passing Parameters to Functions]({{ site.baseurl
}}/dev/batch/index.html#passing-parameters-to-functions)),
-creating and finalizing local state, accessing broadcast variables (see
-[Broadcast Variables]({{ site.baseurl
}}/dev/batch/index.html#broadcast-variables)), and for accessing runtime
-information such as accumulators and counters (see
-[Accumulators and Counters](#accumulators--counters)), and information
-on iterations (see [Iterations]({{ site.baseurl }}/dev/batch/iterations.html)).
+除了用户自定义的功能（map，reduce 等），Rich functions
还提供了四个方法：`open`、`close`、`getRuntimeContext` 和
+`setRuntimeContext`。这些对于参数化功能很有用
+(参阅 [给函数传递参数]({{ site.baseurl
}}/zh/dev/batch/index.html#passing-parameters-to-functions))，
+创建和最终确定本地状态，访问广播变量(参阅
+[广播变量]({{ site.baseurl
}}/zh/dev/batch/index.html#broadcast-variables))，以及访问运行时信息，例如累加器和计数器(参阅
+[累加器和计数器](#累加器和计数器))，以及迭代器的相关信息(参阅 [迭代器]({{ site.baseurl
}}/zh/dev/batch/iterations.html))。
{% top %}
-## Accumulators & Counters
+<a name="accumulators--counters"></a>
-Accumulators are simple constructs with an **add operation** and a **final
accumulated result**,
-which is available after the job ended.
+## 累加器和计数器
-The most straightforward accumulator is a **counter**: You can increment it
using the
-```Accumulator.add(V value)``` method. At the end of the job Flink will sum up
(merge) all partial
-results and send the result to the client. Accumulators are useful during
debugging or if you
-quickly want to find out more about your data.
+累加器是具有**加法运算**和**最终累加结果**的一种简单结构，可在作业结束后使用。
-Flink currently has the following **built-in accumulators**. Each of them
implements the
-{% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/Accumulator.java
"Accumulator" %}
-interface.
+最简单的累加器就是**计数器**: 你可以使用
+```Accumulator.add(V value)``` 方法将其递增。在作业结束时，Flink 会汇总(合并)所有部分的结果并将其发送给客户端。
+在调试过程中或在你想快速了解有关数据更多信息时,累加器作用很大。
+
+Flink 目前有如下**内置累加器**。每个都实现了
+{% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/Accumulator.java
"累加器" %}
+接口。
- {% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/IntCounter.java
"__IntCounter__" %},
{% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/LongCounter.java
"__LongCounter__" %}
- and {% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/DoubleCounter.java
"__DoubleCounter__" %}:
- See below for an example using a counter.
-- {% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/Histogram.java
"__Histogram__" %}:
- A histogram implementation for a discrete number of bins. Internally it is
just a map from Integer
- to Integer. You can use this to compute distributions of values, e.g. the
distribution of
- words-per-line for a word count program.
+ 和 {% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/DoubleCounter.java
"__DoubleCounter__" %}:
+ 有关使用计数器的示例，请参见下文。
+- {% gh_link
/flink-core/src/main/java/org/apache/flink/api/common/accumulators/Histogram.java
"__直方图__" %}:
+ 离散数量的柱状直方图实现。在内部，它只是整形到整形的映射。你可以使用它来计算值的分布，例如，单词计数程序的每行单词的分布情况。
-__How to use accumulators:__
+__如何使用累加器：__
-First you have to create an accumulator object (here a counter) in the
user-defined transformation
-function where you want to use it.
+首先，你要在需要使用累加器的用户自定义的转换函数中创建一个累加器对象（此处是计数器）。
{% highlight java %}
private IntCounter numLines = new IntCounter();
{% endhighlight %}
-Second you have to register the accumulator object, typically in the
```open()``` method of the
-*rich* function. Here you also define the name.
+其次，你必须在富函数的```open()```方法中注册累加器对象。也可以在此处定义名称。
Review comment:
```suggestion
其次，你必须在富函数的 ```open()``` 方法中注册累加器对象。也可以在此处定义名称。
```
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