Github user YolandaMDavis commented on a diff in the pull request:
https://github.com/apache/nifi/pull/354#discussion_r60080948
--- Diff:
nifi-nar-bundles/nifi-standard-bundle/nifi-standard-processors/src/main/java/org/apache/nifi/processors/standard/TransformJSON.java
---
@@ -0,0 +1,212 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.
+ */
+package org.apache.nifi.processors.standard;
+
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.TimeUnit;
+
+import org.apache.nifi.annotation.behavior.EventDriven;
+import org.apache.nifi.annotation.behavior.InputRequirement;
+import org.apache.nifi.annotation.behavior.SideEffectFree;
+import org.apache.nifi.annotation.behavior.SupportsBatching;
+import org.apache.nifi.annotation.documentation.CapabilityDescription;
+import org.apache.nifi.annotation.documentation.Tags;
+import org.apache.nifi.annotation.lifecycle.OnScheduled;
+import org.apache.nifi.components.AllowableValue;
+import org.apache.nifi.components.PropertyDescriptor;
+import org.apache.nifi.components.ValidationContext;
+import org.apache.nifi.components.ValidationResult;
+import org.apache.nifi.components.Validator;
+import org.apache.nifi.flowfile.FlowFile;
+import org.apache.nifi.logging.ProcessorLog;
+import org.apache.nifi.processor.AbstractProcessor;
+import org.apache.nifi.processor.ProcessContext;
+import org.apache.nifi.processor.ProcessSession;
+import org.apache.nifi.processor.ProcessorInitializationContext;
+import org.apache.nifi.processor.Relationship;
+import org.apache.nifi.processor.exception.ProcessException;
+import org.apache.nifi.processor.io.StreamCallback;
+import org.apache.nifi.processor.util.StandardValidators;
+import org.apache.nifi.stream.io.BufferedInputStream;
+import org.apache.nifi.util.StopWatch;
+
+import com.bazaarvoice.jolt.Shiftr;
+import com.bazaarvoice.jolt.Removr;
+import com.bazaarvoice.jolt.Chainr;
+import com.bazaarvoice.jolt.Defaultr;
+import com.bazaarvoice.jolt.Transform;
+import com.bazaarvoice.jolt.JsonUtils;
+
+@EventDriven
+@SideEffectFree
+@SupportsBatching
+@Tags({"json", "jolt", "transform", "shiftr", "chainr", "defaultr",
"removr"})
+@InputRequirement(InputRequirement.Requirement.INPUT_REQUIRED)
+@CapabilityDescription("Applies a list of JOLT specifications to the
flowfile JSON payload. A new FlowFile is created "
+ + "with transformed content and is routed to the 'success'
relationship. If the JSON transform "
+ + "fails, the original FlowFile is routed to the 'failure'
relationship")
+public class TransformJSON extends AbstractProcessor {
+
+ public static final AllowableValue SHIFTR = new
AllowableValue("Shift", "Shift Transform DSL", "This JOLT transformation will
shift input JSON/data to create the output JSON/data.");
+ public static final AllowableValue CHAINR = new
AllowableValue("Chain", "Chain Transform DSL", "Execute list of JOLT
transformations.");
+ public static final AllowableValue DEFAULTR = new
AllowableValue("Default", "Default Transform DSL", " This JOLT transformation
will apply default values to the output JSON/data.");
+ public static final AllowableValue REMOVR = new
AllowableValue("Remove", "Remove Transform DSL", " This JOLT transformation
will apply default values to the output JSON/data.");
+
+ public static final PropertyDescriptor JOLT_SPEC = new
PropertyDescriptor.Builder()
+ .name("Jolt Specification")
+ .description("Jolt Specification for transform of JSON data.")
+ .required(true)
+ .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
+ .addValidator(new JOLTSpecValidator())
+ .required(true)
+ .build();
+
+ public static final PropertyDescriptor JOLT_TRANSFORM = new
PropertyDescriptor.Builder()
+ .name("Jolt Transformation")
+ .description("Specifies the Jolt Transformation that should be
used with the provided specification.")
+ .required(true)
+ .allowableValues(SHIFTR, CHAINR, DEFAULTR, REMOVR)
+ .defaultValue(CHAINR.getValue())
+ .build();
+
+ public static final Relationship REL_SUCCESS = new
Relationship.Builder()
+ .name("success")
+ .description("The FlowFile with transformed content will be
routed to this relationship")
+ .build();
+ public static final Relationship REL_FAILURE = new
Relationship.Builder()
+ .name("failure")
+ .description("If a FlowFile fails processing for any reason
(for example, the FlowFile is not valid JSON), it will be routed to this
relationship")
+ .build();
+
+ private List<PropertyDescriptor> properties;
+ private Set<Relationship> relationships;
+ private Transform transform;
+
+
+ @Override
+ protected void init(ProcessorInitializationContext context) {
+ final List<PropertyDescriptor> properties = new ArrayList<>();
+ properties.add(JOLT_TRANSFORM);
+ properties.add(JOLT_SPEC);
+ this.properties = Collections.unmodifiableList(properties);
+
+ final Set<Relationship> relationships = new HashSet<>();
+ relationships.add(REL_SUCCESS);
+ relationships.add(REL_FAILURE);
+ this.relationships = Collections.unmodifiableSet(relationships);
+ }
+
+ @Override
+ public Set<Relationship> getRelationships() {
+ return relationships;
+ }
+
+ @Override
+ protected List<PropertyDescriptor> getSupportedPropertyDescriptors() {
+ return properties;
+ }
+
+ @Override
+ public void onTrigger(final ProcessContext context, ProcessSession
session) throws ProcessException {
+
+ final FlowFile original = session.get();
+ if (original == null) {
+ return;
+ }
+
+ final ProcessorLog logger = getLogger();
+ final StopWatch stopWatch = new StopWatch(true);
+
+ try {
+
+ FlowFile transformed = session.write(original, new
StreamCallback() {
+ @Override
+ public void process(final InputStream rawIn, final
OutputStream out) throws IOException {
+
+ try (final InputStream in = new
BufferedInputStream(rawIn)) {
+ Object inputJson = JsonUtils.jsonToObject(in);
+ Object transformedJson =
transform.transform(inputJson);
+
out.write(JsonUtils.toJsonString(transformedJson).getBytes());
+ } catch (final Exception e) {
+ throw new IOException(e);
--- End diff --
I was following the pattern set by the TransformXML, however my thoughts
around the catch/rethrow is to ensure that whatever exception is generated by
the JsonUtils or the Transform object will be handled gracefully. Looking at
the StandardProcessSession as an example, the rethrown IOException appears to
be later caught and rethrown as a ProcessException, which the code catches,
logs and then issues a transfer to failure.
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