INT-4029: TCP: Add Buffer Pooling to Deserializers

JIRA: https://jira.spring.io/browse/INT-4029

Support the use of buffer pools in the deserializer code to
allow buffer reuse.

spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/serializer/AbstractByteArraySerializer.java

@@ -75,22 +75,6 @@ public abstract class AbstractByteArraySerializer implements
 		}
 	}
 
-	/**
-	 * Copy size bytes to a new buffer exactly size bytes long.
-	 * @param buffer The buffer containing the data.
-	 * @param size The number of bytes to copy.
-	 * @return The new buffer, or the buffer parameter if it is
-	 * already the correct size.
-	 */
-	protected byte[] copyToSizedArray(byte[] buffer, int size) {
-		if (size == buffer.length) {
-			return buffer;
-		}
-		byte[] assembledData = new byte[size];
-		System.arraycopy(buffer, 0, assembledData, 0, size);
-		return assembledData;
-	}
-
 	protected void publishEvent(Exception cause, byte[] buffer, int offset) {
 		TcpDeserializationExceptionEvent event = new TcpDeserializationExceptionEvent(this, cause, buffer, offset);
 		if (this.applicationEventPublisher != null) {

spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/serializer/AbstractPooledBufferByteArraySerializer.java

@@ -0,0 +1,117 @@
+/*
+ * Copyright 2016 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.ip.tcp.serializer;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+import org.springframework.integration.util.SimplePool;
+import org.springframework.integration.util.SimplePool.PoolItemCallback;
+import org.springframework.util.Assert;
+
+/**
+ * Base class for deserializers that cannot determine the buffer size needed.
+ * Optionally pools buffers.
+ *
+ * @author Gary Russell
+ * @since 4.3
+ *
+ */
+public abstract class AbstractPooledBufferByteArraySerializer extends AbstractByteArraySerializer {
+
+	private SimplePool<byte[]> pool;
+
+	private long poolWaitTimeout = Long.MAX_VALUE;
+
+	/**
+	 * Set the pool size for deserialization buffers.
+	 * @param size the size, -1 for unlimited.
+	 * @since 4.3
+	 */
+	public void setPoolSize(int size) {
+		Assert.isNull(this.pool, "Cannot change pool size once set");
+		this.pool = new SimplePool<byte[]>(size, new PoolItemCallback<byte[]>() {
+
+			@Override
+			public byte[] createForPool() {
+				return new byte[getMaxMessageSize()];
+			}
+
+			@Override
+			public boolean isStale(byte[] item) {
+				return false; // never stale
+			}
+
+			@Override
+			public void removedFromPool(byte[] item) {
+			}
+
+		});
+		this.pool.setWaitTimeout(this.poolWaitTimeout);
+	}
+
+	/**
+	 * Set the pool wait timeout if a pool is configured, default unlimited.
+	 * @param poolWaitTimeout the timeout.
+	 */
+	public void setPoolWaitTimeout(long poolWaitTimeout) {
+		this.poolWaitTimeout = poolWaitTimeout;
+		if (this.pool != null) {
+			this.pool.setWaitTimeout(poolWaitTimeout);
+		}
+	}
+
+	@Override
+	public final byte[] deserialize(InputStream inputStream) throws IOException {
+		byte[] buffer = this.pool == null ? new byte[this.maxMessageSize] : this.pool.getItem();
+		try {
+			return doDeserialize(inputStream, buffer);
+		}
+		finally {
+			if (this.pool != null) {
+				this.pool.releaseItem(buffer);
+			}
+		}
+	}
+
+	/**
+	 * @param inputStream the input stream.
+	 * @param buffer the raw working buffer (maxMessageSize).
+	 * @return the decoded bytes.
+	 * @throws IOException an io exception.
+	 * @since 4.3
+	 */
+	protected abstract byte[] doDeserialize(InputStream inputStream, byte[] buffer) throws IOException;
+
+	/**
+	 * Copy size bytes to a new buffer exactly size bytes long. If a pool is not
+	 * in use and the array is already the correct length, it is simply returned.
+	 * @param buffer The buffer containing the data.
+	 * @param size The number of bytes to copy.
+	 * @return The new buffer, or the buffer parameter if it is
+	 * already the correct size and there is no pool.
+	 */
+	protected byte[] copyToSizedArray(byte[] buffer, int size) {
+		if (size == buffer.length && this.pool == null) {
+			return buffer;
+		}
+		byte[] assembledData = new byte[size];
+		System.arraycopy(buffer, 0, assembledData, 0, size);
+		return assembledData;
+	}
+
+}

spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/serializer/ByteArrayCrLfSerializer.java

@@ -28,7 +28,7 @@ import java.io.OutputStream;
  * @author Gary Russell
  * @since 2.0
  */
-public class ByteArrayCrLfSerializer extends AbstractByteArraySerializer {
+public class ByteArrayCrLfSerializer extends AbstractPooledBufferByteArraySerializer {
 
 	private static final byte[] CRLF = "\r\n".getBytes();
 
@@ -39,8 +39,7 @@ public class ByteArrayCrLfSerializer extends AbstractByteArraySerializer {
 	 * being read).
 	 */
 	@Override
-	public byte[] deserialize(InputStream inputStream) throws IOException {
-		byte[] buffer = new byte[this.maxMessageSize];
+	public byte[] doDeserialize(InputStream inputStream, byte[] buffer) throws IOException {
 		int n = this.fillToCrLf(inputStream, buffer);
 		return this.copyToSizedArray(buffer, n);
 	}

spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/serializer/ByteArrayRawSerializer.java

@@ -41,7 +41,7 @@ import java.net.SocketTimeoutException;
  * @since 2.0.3
  *
  */
-public class ByteArrayRawSerializer extends AbstractByteArraySerializer {
+public class ByteArrayRawSerializer extends AbstractPooledBufferByteArraySerializer {
 
 	private final boolean treatTimeoutAsEndOfMessage;
 
@@ -66,8 +66,7 @@ public class ByteArrayRawSerializer extends AbstractByteArraySerializer {
 	}
 
 	@Override
-	public byte[] deserialize(InputStream inputStream) throws IOException {
-		byte[] buffer = new byte[this.maxMessageSize];
+	protected byte[] doDeserialize(InputStream inputStream, byte[] buffer) throws IOException {
 		int n = 0;
 		int bite = 0;
 		if (logger.isDebugEnabled()) {
@@ -90,15 +89,13 @@ public class ByteArrayRawSerializer extends AbstractByteArraySerializer {
 					}
 					break;
 				}
-				buffer[n++] = (byte) bite;
 				if (n >= this.maxMessageSize) {
 					throw new IOException("Socket was not closed before max message length: "
 							+ this.maxMessageSize);
 				}
+				buffer[n++] = (byte) bite;
 			}
-			byte[] assembledData = new byte[n];
-			System.arraycopy(buffer, 0, assembledData, 0, n);
-			return assembledData;
+			return copyToSizedArray(buffer, n);
 		}
 		catch (SoftEndOfStreamException e) {
 			throw e;

spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/serializer/ByteArraySingleTerminatorSerializer.java

@@ -28,7 +28,7 @@ import java.io.OutputStream;
  * @author Gary Russell
  * @since 2.2
  */
-public class ByteArraySingleTerminatorSerializer extends AbstractByteArraySerializer {
+public class ByteArraySingleTerminatorSerializer extends AbstractPooledBufferByteArraySerializer {
 
 	private final byte terminator;
 
@@ -43,8 +43,7 @@ public class ByteArraySingleTerminatorSerializer extends AbstractByteArraySerial
 	 * being read).
 	 */
 	@Override
-	public byte[] deserialize(InputStream inputStream) throws IOException {
-		byte[] buffer = new byte[this.maxMessageSize];
+	protected byte[] doDeserialize(InputStream inputStream, byte[] buffer) throws IOException {
 		int n = 0;
 		int bite;
 		if (logger.isDebugEnabled()) {
@@ -67,9 +66,7 @@ public class ByteArraySingleTerminatorSerializer extends AbstractByteArraySerial
 							+ this.maxMessageSize);
 				}
 			}
-			byte[] assembledData = new byte[n];
-			System.arraycopy(buffer, 0, assembledData, 0, n);
-			return assembledData;
+			return copyToSizedArray(buffer, n);
 		}
 		catch (SoftEndOfStreamException e) {
 			throw e;

spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/serializer/ByteArrayStxEtxSerializer.java

@@ -30,7 +30,7 @@ import org.springframework.integration.mapping.MessageMappingException;
  * @author Gary Russell
  * @since 2.0
  */
-public class ByteArrayStxEtxSerializer extends AbstractByteArraySerializer {
+public class ByteArrayStxEtxSerializer extends AbstractPooledBufferByteArraySerializer {
 
 	public static final int STX = 0x02;
 
@@ -45,18 +45,16 @@ public class ByteArrayStxEtxSerializer extends AbstractByteArraySerializer {
 	 *
 	 */
 	@Override
-	public byte[] deserialize(InputStream inputStream) throws IOException {
+	public byte[] doDeserialize(InputStream inputStream, byte[] buffer) throws IOException {
 		int bite = inputStream.read();
 		if (bite < 0) {
 			throw new SoftEndOfStreamException("Stream closed between payloads");
 		}
-		byte[] buffer = null;
 		int n = 0;
 		try {
 			if (bite != STX) {
 				throw new MessageMappingException("Expected STX to begin message");
 			}
-			buffer = new byte[this.maxMessageSize];
 			while ((bite = inputStream.read()) != ETX) {
 				checkClosure(bite);
 				buffer[n++] = (byte) bite;
@@ -65,9 +63,7 @@ public class ByteArrayStxEtxSerializer extends AbstractByteArraySerializer {
 							+ this.maxMessageSize);
 				}
 			}
-			byte[] assembledData = new byte[n];
-			System.arraycopy(buffer, 0, assembledData, 0, n);
-			return assembledData;
+			return copyToSizedArray(buffer, n);
 		}
 		catch (IOException e) {
 			publishEvent(e, buffer, n);

spring-integration-ip/src/test/java/org/springframework/integration/ip/tcp/serializer/PooledDeserializationTests.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright 2016 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.ip.tcp.serializer;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotSame;
+import static org.junit.Assert.fail;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.util.Set;
+
+import org.junit.Test;
+
+import org.springframework.integration.test.util.TestUtils;
+
+/**
+ * @author Gary Russell
+ * @since 4.3
+ *
+ */
+public class PooledDeserializationTests {
+
+	@Test
+	public void testCRLF() throws IOException {
+		ByteArrayCrLfSerializer deser = new ByteArrayCrLfSerializer();
+		deser.setPoolSize(2);
+		ByteArrayInputStream bais = new ByteArrayInputStream("foo\r\n".getBytes());
+		for (int i = 0; i < 5; i++) {
+			bais.reset();
+			byte[] bytes = deser.deserialize(bais);
+			assertEquals("foo", new String(bytes));
+		}
+		try {
+			deser.deserialize(bais);
+			fail("Expected SoftEndOfStreamException");
+		}
+		catch (SoftEndOfStreamException e) {
+			// expected
+		}
+		assertEquals(1, TestUtils.getPropertyValue(deser, "pool.allocated", Set.class).size());
+		assertEquals(0, TestUtils.getPropertyValue(deser, "pool.inUse", Set.class).size());
+	}
+
+	@Test
+	public void testRawMaxMessageSizeEqualDontReturnPooledItem() throws IOException {
+		ByteArrayRawSerializer deser = new ByteArrayRawSerializer();
+		deser.setPoolSize(2);
+		deser.setMaxMessageSize(3);
+		ByteArrayInputStream bais = new ByteArrayInputStream("foo".getBytes());
+		byte[] bytes = deser.deserialize(bais);
+		assertEquals("foo", new String(bytes));
+		assertEquals(1, TestUtils.getPropertyValue(deser, "pool.allocated", Set.class).size());
+		assertEquals(0, TestUtils.getPropertyValue(deser, "pool.inUse", Set.class).size());
+		assertNotSame(bytes, TestUtils.getPropertyValue(deser, "pool.allocated", Set.class).iterator().next());
+	}
+
+}