INT-2853 ObjectToStringTransformer Improvements

* Convert byte[] and char[] to String rather than simply using toString().
* Allow the charset to be configured for byte[] payloads.
* Add tests.
* Add reference documentation updates.

spring-integration-core/src/test/java/org/springframework/integration/config/xml/ObjectToStringTransformerParserTests-context.xml

@@ -23,4 +23,7 @@
 		<poller fixed-delay="10000"/>
 	</object-to-string-transformer>
 
+	<object-to-string-transformer id="withCharset" charset="FOO"
+		input-channel="charsetChannel" output-channel="nullChannel"/>
+
 </beans:beans>

spring-integration-core/src/test/java/org/springframework/integration/config/xml/ObjectToStringTransformerParserTests.java

@@ -21,13 +21,14 @@ import static org.junit.Assert.assertNotNull;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
-
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.integration.Message;
 import org.springframework.integration.MessageChannel;
 import org.springframework.integration.core.PollableChannel;
+import org.springframework.integration.endpoint.AbstractEndpoint;
 import org.springframework.integration.message.GenericMessage;
+import org.springframework.integration.test.util.TestUtils;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 
@@ -50,6 +51,8 @@ public class ObjectToStringTransformerParserTests {
 	@Qualifier("output")
 	private PollableChannel output;
 
+	@Autowired
+	private AbstractEndpoint withCharset;
 
 	@Test
 	public void directChannelWithStringMessage() {
@@ -83,9 +86,14 @@ public class ObjectToStringTransformerParserTests {
 		assertEquals("test", result.getPayload());
 	}
 
+	@Test
+	public void charset() {
+		assertEquals("FOO", TestUtils.getPropertyValue(this.withCharset, "handler.transformer.charset"));
+	}
 
 	private static class TestBean {
 
+		@Override
 		public String toString() {
 			return "test";
 		}

spring-integration-core/src/test/java/org/springframework/integration/transformer/ObjectToStringTransformerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2010 the original author or authors.
+ * Copyright 2002-2013 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,13 +18,16 @@ package org.springframework.integration.transformer;
 
 import static org.junit.Assert.assertEquals;
 
-import org.junit.Test;
+import java.nio.charset.Charset;
 
+import org.junit.Test;
 import org.springframework.integration.Message;
 import org.springframework.integration.message.GenericMessage;
 
 /**
  * @author Mark Fisher
+ * @author Andrew Cowlin
+ * @author Gary Russell
  */
 public class ObjectToStringTransformerTests {
 
@@ -42,9 +45,31 @@ public class ObjectToStringTransformerTests {
 		assertEquals("test", result.getPayload());
 	}
 
+	@Test
+	public void byteArrayPayload() throws Exception {
+		Transformer transformer = new ObjectToStringTransformer();
+		Message<?> result = transformer.transform(new GenericMessage<byte[]>(("foo" + '\u0fff').getBytes("UTF-8")));
+		assertEquals("foo" + '\u0fff', result.getPayload());
+	}
+
+	@Test
+	public void byteArrayPayloadCharset() throws Exception {
+		String defaultCharsetName = Charset.defaultCharset().toString();
+		Transformer transformer = new ObjectToStringTransformer(defaultCharsetName);
+		Message<?> result = transformer.transform(new GenericMessage<byte[]>("foo".getBytes(defaultCharsetName)));
+		assertEquals("foo", result.getPayload());
+	}
+
+	@Test
+	public void charArrayPayload() {
+		Transformer transformer = new ObjectToStringTransformer();
+		Message<?> result = transformer.transform(new GenericMessage<char[]>("foo".toCharArray()));
+		assertEquals("foo", result.getPayload());
+	}
 
 	private static class TestBean {
 
+		@Override
 		public String toString() {
 			return "test";
 		}