DATAREDIS-1212 - Polishing.

Remove overly pessimistic null checks. Use constant when channel/body are empty to avoid allocations. Remove superfluous final keywords.

Original pull request: #559.

Author: mp911de

src/main/java/org/springframework/data/redis/connection/DefaultMessage.java

@@ -23,9 +23,11 @@
  *
  * @author Costin Leau
  * @author Christoph Strobl
+ * @author Mark Paluch
  */
 public class DefaultMessage implements Message {
 
+	private static final byte[] EMPTY = new byte[0];
 	private final byte[] channel;
 	private final byte[] body;
 	private @Nullable String toString;
@@ -39,15 +41,14 @@ public DefaultMessage(byte[] channel, byte[] body) {
 		this.channel = channel;
 	}
 
-	/**
-	 * @return
-	 */
+	@Override
 	public byte[] getChannel() {
-		return channel.clone();
+		return channel.length == 0 ? EMPTY : channel.clone();
 	}
 
+	@Override
 	public byte[] getBody() {
-		return body.clone();
+		return body.length == 0 ? EMPTY : body.clone();
 	}
 
 	@Override

src/main/java/org/springframework/data/redis/core/RedisKeyValueAdapter.java

@@ -808,8 +808,9 @@ public void onMessage(Message message, @Nullable byte[] pattern) {
 
 			Object value = CollectionUtils.isEmpty(hash) ? null : converter.read(Object.class, new RedisData(hash));
 
-			String channel = !ObjectUtils.isEmpty(message.getChannel())
-					? converter.getConversionService().convert(message.getChannel(), String.class)
+			byte[] channelAsBytes = message.getChannel();
+			String channel = !ObjectUtils.isEmpty(channelAsBytes)
+					? converter.getConversionService().convert(channelAsBytes, String.class)
 					: null;
 
 			RedisKeyExpiredEvent event = new RedisKeyExpiredEvent(channel, key, value);
@@ -825,11 +826,6 @@ public void onMessage(Message message, @Nullable byte[] pattern) {
 		}
 
 		private boolean isKeyExpirationMessage(Message message) {
-
-			if (message == null) {
-				return false;
-			}
-
 			return BinaryKeyspaceIdentifier.isValid(message.getBody());
 		}
 	}

src/main/java/org/springframework/data/redis/core/convert/MappingRedisConverter.java

@@ -1303,7 +1303,7 @@ public static BinaryKeyspaceIdentifier of(byte[] key) {
 		 */
 		public static boolean isValid(byte[] key) {
 
-			if (key == null) {
+			if (key.length == 0) {
 				return false;
 			}
 

src/main/java/org/springframework/data/redis/listener/KeyspaceEventMessageListener.java

@@ -60,7 +60,7 @@ public KeyspaceEventMessageListener(RedisMessageListenerContainer listenerContai
 	@Override
 	public void onMessage(Message message, @Nullable byte[] pattern) {
 
-		if (message == null || ObjectUtils.isEmpty(message.getChannel()) || ObjectUtils.isEmpty(message.getBody())) {
+		if (ObjectUtils.isEmpty(message.getChannel()) || ObjectUtils.isEmpty(message.getBody())) {
 			return;
 		}
 

src/main/java/org/springframework/data/redis/listener/RedisMessageListenerContainer.java

@@ -979,10 +979,11 @@ public void onMessage(Message message, @Nullable byte[] pattern) {
 		}
 	}
 
-	private void dispatchMessage(Collection<MessageListener> listeners, final Message message, final byte[] pattern) {
-		final byte[] source = (pattern != null ? pattern.clone() : message.getChannel());
+	private void dispatchMessage(Collection<MessageListener> listeners, Message message, @Nullable byte[] pattern) {
 
-		for (final MessageListener messageListener : listeners) {
+		byte[] source = (pattern != null ? pattern.clone() : message.getChannel());
+
+		for (MessageListener messageListener : listeners) {
 			taskExecutor.execute(() -> processMessage(messageListener, message, source));
 		}
 	}

src/test/java/org/springframework/data/redis/core/convert/BinaryKeyspaceIdentifierUnitTests.java

@@ -31,7 +31,6 @@ public class BinaryKeyspaceIdentifierUnitTests {
 	@Test // DATAREDIS-744
 	public void shouldReturnIfKeyIsValid() {
 
-		assertThat(BinaryKeyspaceIdentifier.isValid(null)).isFalse();
 		assertThat(BinaryKeyspaceIdentifier.isValid("foo".getBytes())).isFalse();
 		assertThat(BinaryKeyspaceIdentifier.isValid("".getBytes())).isFalse();
 		assertThat(BinaryKeyspaceIdentifier.isValid("foo:bar".getBytes())).isTrue();

src/test/java/org/springframework/data/redis/listener/KeyExpirationEventMessageListenerUnitTests.java

@@ -64,14 +64,6 @@ public void handleMessageShouldPublishKeyExpiredEvent() {
 		assertThat((byte[]) captor.getValue().getSource()).isEqualTo(MESSAGE_BODY.getBytes());
 	}
 
-	@Test // DATAREDIS-425
-	public void handleMessageShouldNotRespondToNullMessage() {
-
-		listener.onMessage(null, "*".getBytes());
-
-		verifyZeroInteractions(publisherMock);
-	}
-
 	@Test // DATAREDIS-425, DATAREDIS-692
 	public void handleMessageShouldNotRespondToEmptyMessage() {