NIFI-7482 Changed InvokeHTTP to be extensible.

Added unit test.

This closes #4291.

Signed-off-by: Arpad Boda <aboda@apache.org>

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

@@ -134,7 +134,7 @@ import org.joda.time.format.DateTimeFormatter;
                 + " where the <NAME> will be the form data name, will be used to fill out the multipart form parts."
                 + "  If send message body is false, the flowfile will not be sent, but any other form data will be.")
 })
-public final class InvokeHTTP extends AbstractProcessor {
+public class InvokeHTTP extends AbstractProcessor {
     // flowfile attribute keys returned after reading the response
     public final static String STATUS_CODE = "invokehttp.status.code";
     public final static String STATUS_MESSAGE = "invokehttp.status.message";

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

@@ -16,6 +16,7 @@
  */
 package org.apache.nifi.processors.standard;
 
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 
@@ -273,6 +274,7 @@ public class TestInvokeHTTP extends TestInvokeHttpCommon {
         assertNull(regexAttributesToSendField.get(processor));
 
     }
+
     @Test
     public void testEmptyGzipHttpReponse() throws Exception {
         addHandler(new EmptyGzipResponseHandler());
@@ -300,6 +302,31 @@ public class TestInvokeHTTP extends TestInvokeHttpCommon {
         bundle.assertAttributeEquals("Content-Type", "text/plain");
     }
 
+    @Test
+    public void testShouldAllowExtension() {
+        // Arrange
+        class ExtendedInvokeHTTP extends InvokeHTTP {
+            private int extendedNumber = -1;
+
+            public ExtendedInvokeHTTP(int num) {
+                super();
+                this.extendedNumber = num;
+            }
+
+            public int extendedMethod() {
+                return this.extendedNumber;
+            }
+        }
+
+        int num = Double.valueOf(Math.random() * 100).intValue();
+
+        // Act
+        ExtendedInvokeHTTP eih = new ExtendedInvokeHTTP(num);
+
+        // Assert
+        assertEquals(num, eih.extendedMethod());
+    }
+
     public static class EmptyGzipResponseHandler extends AbstractHandler {
 
         @Override