NIFI-2912 Allow custom text in GenerateFlowFile

This closes #1206.

Signed-off-by: Andy LoPresto <alopresto@apache.org>

nifi-nar-bundles/nifi-standard-bundle/nifi-standard-processors/src/main/java/org/apache/nifi/processors/standard/GenerateFlowFile.java

@@ -19,6 +19,7 @@ package org.apache.nifi.processors.standard;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
@@ -33,6 +34,8 @@ 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.PropertyDescriptor;
+import org.apache.nifi.components.ValidationContext;
+import org.apache.nifi.components.ValidationResult;
 import org.apache.nifi.flowfile.FlowFile;
 import org.apache.nifi.processor.AbstractProcessor;
 import org.apache.nifi.processor.DataUnit;
@@ -58,6 +61,7 @@ public class GenerateFlowFile extends AbstractProcessor {
             .name("File Size")
             .description("The size of the file that will be used")
             .required(true)
+            .defaultValue("0B")
             .addValidator(StandardValidators.DATA_SIZE_VALIDATOR)
             .build();
     public static final PropertyDescriptor BATCH_SIZE = new PropertyDescriptor.Builder()
@@ -71,7 +75,7 @@ public class GenerateFlowFile extends AbstractProcessor {
             .name("Data Format")
             .description("Specifies whether the data should be Text or Binary")
             .required(true)
-            .defaultValue(DATA_FORMAT_BINARY)
+            .defaultValue(DATA_FORMAT_TEXT)
             .allowableValues(DATA_FORMAT_BINARY, DATA_FORMAT_TEXT)
             .build();
     public static final PropertyDescriptor UNIQUE_FLOWFILES = new PropertyDescriptor.Builder()
@@ -82,6 +86,16 @@ public class GenerateFlowFile extends AbstractProcessor {
             .allowableValues("true", "false")
             .defaultValue("false")
             .build();
+    public static final PropertyDescriptor CUSTOM_TEXT = new PropertyDescriptor.Builder()
+            .displayName("Custom Text")
+            .name("generate-ff-custom-text")
+            .description("If Data Format is text and if Unique FlowFiles is false, then this custom text will be used as content of the generated "
+                    + "FlowFiles and the File Size will be ignored. Finally, if Expression Language is used, evaluation will be performed only once "
+                    + "per batch of generated FlowFiles")
+            .required(false)
+            .expressionLanguageSupported(true)
+            .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
+            .build();
 
     public static final Relationship SUCCESS = new Relationship.Builder()
             .name("success")
@@ -99,6 +113,7 @@ public class GenerateFlowFile extends AbstractProcessor {
         descriptors.add(BATCH_SIZE);
         descriptors.add(DATA_FORMAT);
         descriptors.add(UNIQUE_FLOWFILES);
+        descriptors.add(CUSTOM_TEXT);
         this.descriptors = Collections.unmodifiableList(descriptors);
 
         final Set<Relationship> relationships = new HashSet<>();
@@ -120,10 +135,24 @@ public class GenerateFlowFile extends AbstractProcessor {
     public void onScheduled(final ProcessContext context) {
         if (context.getProperty(UNIQUE_FLOWFILES).asBoolean()) {
             this.data.set(null);
-        } else {
+        } else if(!context.getProperty(CUSTOM_TEXT).isSet()) {
             this.data.set(generateData(context));
         }
+    }
 
+    @Override
+    protected Collection<ValidationResult> customValidate(ValidationContext validationContext) {
+        final List<ValidationResult> results = new ArrayList<>(1);
+        final boolean isUnique = validationContext.getProperty(UNIQUE_FLOWFILES).asBoolean();
+        final boolean isText = validationContext.getProperty(DATA_FORMAT).getValue().equals(DATA_FORMAT_TEXT);
+        final boolean isCustom = validationContext.getProperty(CUSTOM_TEXT).isSet();
+
+        if(isCustom && (isUnique || !isText)) {
+            results.add(new ValidationResult.Builder().subject("Custom Text").valid(false).explanation("If Custom Text is set, then Data Format must be "
+                    + "text and Unique FlowFiles must be false.").build());
+        }
+
+        return results;
     }
 
     private byte[] generateData(final ProcessContext context) {
@@ -148,6 +177,8 @@ public class GenerateFlowFile extends AbstractProcessor {
         final byte[] data;
         if (context.getProperty(UNIQUE_FLOWFILES).asBoolean()) {
             data = generateData(context);
+        } else if(context.getProperty(CUSTOM_TEXT).isSet()) {
+            data = context.getProperty(CUSTOM_TEXT).evaluateAttributeExpressions().getValue().getBytes();
         } else {
             data = this.data.get();
         }

nifi-nar-bundles/nifi-standard-bundle/nifi-standard-processors/src/test/java/org/apache/nifi/processors/standard/TestGenerateFlowFile.java

@@ -0,0 +1,56 @@
+/*
+ * 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 org.apache.nifi.util.TestRunner;
+import org.apache.nifi.util.TestRunners;
+import org.junit.Test;
+
+/**
+ * Unit tests for the GenerateFlowFile processor.
+ */
+public class TestGenerateFlowFile {
+
+    @Test
+    public void testGenerateCustomText() throws IOException {
+        TestRunner runner = TestRunners.newTestRunner(new GenerateFlowFile());
+        runner.setProperty(GenerateFlowFile.FILE_SIZE, "100MB");
+        runner.setProperty(GenerateFlowFile.DATA_FORMAT, GenerateFlowFile.DATA_FORMAT_TEXT);
+        runner.setProperty(GenerateFlowFile.CUSTOM_TEXT, "This is my custom text!");
+
+        runner.run();
+
+        runner.assertTransferCount(GenerateFlowFile.SUCCESS, 1);
+        runner.getFlowFilesForRelationship(GenerateFlowFile.SUCCESS).get(0).assertContentEquals("This is my custom text!");
+    }
+
+    @Test
+    public void testInvalidCustomText() throws IOException {
+        TestRunner runner = TestRunners.newTestRunner(new GenerateFlowFile());
+        runner.setProperty(GenerateFlowFile.FILE_SIZE, "100MB");
+        runner.setProperty(GenerateFlowFile.DATA_FORMAT, GenerateFlowFile.DATA_FORMAT_BINARY);
+        runner.setProperty(GenerateFlowFile.CUSTOM_TEXT, "This is my custom text!");
+        runner.assertNotValid();
+
+        runner.setProperty(GenerateFlowFile.DATA_FORMAT, GenerateFlowFile.DATA_FORMAT_TEXT);
+        runner.setProperty(GenerateFlowFile.UNIQUE_FLOWFILES, "true");
+        runner.assertNotValid();
+    }
+
+}