INT-4255: JSON Embedded Headers Message Mapper

JIRA: https://jira.spring.io/browse/INT-4255

- Support embedding headers for transports that don't support headers (TCP, Kafka, etc)
- Use the new message-aware Jackson ObjectMapper
- Provide a mechanism to more efficiently support byte[] payloads (avoid Base64 encoding)
- Support decoding "legacy" SCSt embedded headers

Polishing; PR Comments - Add Support to MQTT and TCP

Switch to simple patterns instead of regex

* Fix JavaDoc typo
* Upgrade to Jackson 2.9.1

spring-integration-core/src/test/java/org/springframework/integration/support/json/EmbeddedJsonHeadersMessageMapperTests.java

@@ -0,0 +1,117 @@
+/*
+ * Copyright 2017 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.
+ * 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.springframework.integration.support.json;
+
+import static org.hamcrest.CoreMatchers.containsString;
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.CoreMatchers.not;
+import static org.junit.Assert.assertThat;
+
+import java.nio.ByteBuffer;
+import java.util.Collections;
+
+import org.junit.Test;
+
+import org.springframework.messaging.Message;
+import org.springframework.messaging.support.GenericMessage;
+
+/**
+ * @author Gary Russell
+ * @since 5.0
+ *
+ */
+public class EmbeddedJsonHeadersMessageMapperTests {
+
+	@Test
+	public void testEmbedAll() throws Exception {
+		EmbeddedJsonHeadersMessageMapper mapper = new EmbeddedJsonHeadersMessageMapper();
+		GenericMessage<String> message = new GenericMessage<>("foo");
+		assertThat(mapper.toMessage(mapper.fromMessage(message)), equalTo(message));
+
+	}
+
+	@Test
+	public void testEmbedSome() throws Exception {
+		EmbeddedJsonHeadersMessageMapper mapper = new EmbeddedJsonHeadersMessageMapper("id");
+		GenericMessage<String> message = new GenericMessage<>("foo");
+		Message<?> decoded = mapper.toMessage(mapper.fromMessage(message));
+		assertThat(decoded.getPayload(), equalTo(message.getPayload()));
+		assertThat(decoded.getHeaders().getId(), equalTo(message.getHeaders().getId()));
+	}
+
+	@Test
+	public void testBytesEmbedAll() throws Exception {
+		EmbeddedJsonHeadersMessageMapper mapper = new EmbeddedJsonHeadersMessageMapper();
+		GenericMessage<byte[]> message = new GenericMessage<>("foo".getBytes());
+		Thread.sleep(2);
+		byte[] bytes = mapper.fromMessage(message);
+		ByteBuffer bb = ByteBuffer.wrap(bytes);
+		int headerLen = bb.getInt();
+		byte[] headerBytes = new byte[headerLen];
+		bb.get(headerBytes);
+		String headers = new String(headerBytes);
+		assertThat(headers, containsString(message.getHeaders().getId().toString()));
+		assertThat(headers, containsString(String.valueOf(message.getHeaders().getTimestamp())));
+		assertThat(bb.getInt(), equalTo(3));
+		assertThat(bb.remaining(), equalTo(3));
+		assertThat((char) bb.get(), equalTo('f'));
+		assertThat((char) bb.get(), equalTo('o'));
+		assertThat((char) bb.get(), equalTo('o'));
+	}
+
+	@Test
+	public void testBytesEmbedSome() throws Exception {
+		EmbeddedJsonHeadersMessageMapper mapper = new EmbeddedJsonHeadersMessageMapper("I*");
+		GenericMessage<byte[]> message = new GenericMessage<>("foo".getBytes(), Collections.singletonMap("bar", "baz"));
+		byte[] bytes = mapper.fromMessage(message);
+		ByteBuffer bb = ByteBuffer.wrap(bytes);
+		int headerLen = bb.getInt();
+		byte[] headerBytes = new byte[headerLen];
+		bb.get(headerBytes);
+		String headers = new String(headerBytes);
+		assertThat(headers, containsString(message.getHeaders().getId().toString()));
+		assertThat(headers, not(containsString("bar")));
+		assertThat(bb.getInt(), equalTo(3));
+		assertThat(bb.remaining(), equalTo(3));
+		assertThat((char) bb.get(), equalTo('f'));
+		assertThat((char) bb.get(), equalTo('o'));
+		assertThat((char) bb.get(), equalTo('o'));
+	}
+
+	@Test
+	public void testBytesEmbedAllJson() throws Exception {
+		EmbeddedJsonHeadersMessageMapper mapper = new EmbeddedJsonHeadersMessageMapper();
+		mapper.setRawBytes(false);
+		GenericMessage<byte[]> message = new GenericMessage<>("foo".getBytes());
+		byte[] mappedBytes = mapper.fromMessage(message);
+		String mapped = new String(mappedBytes);
+		assertThat(mapped, containsString("[B\",\"Zm9v"));
+		@SuppressWarnings("unchecked")
+		Message<byte[]> decoded = (Message<byte[]>) mapper.toMessage(mappedBytes);
+		assertThat(new String(decoded.getPayload()), equalTo("foo"));
+
+	}
+
+	@Test
+	public void testBytesDecodeAll() throws Exception {
+		EmbeddedJsonHeadersMessageMapper mapper = new EmbeddedJsonHeadersMessageMapper();
+		GenericMessage<byte[]> message = new GenericMessage<>("foo".getBytes());
+		Message<?> decoded = mapper.toMessage(mapper.fromMessage(message));
+		assertThat(decoded, equalTo(message));
+	}
+
+}