INT-3293: Add Lambda Strategies

JIRA: https://jira.springsource.org/browse/INT-3293

spring-integration-core/src/main/java/org/springframework/integration/core/GenericSelector.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2002-2010 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.core;
+
+/**
+ * Generic (lambda) strategy interface for selector.
+ *
+ * @param <S> the source type to accept.
+ *
+ * @author Artem Bilan
+ * @since 4.0
+ */
+public interface GenericSelector<S> {
+
+	boolean accept(S source);
+
+}

spring-integration-core/src/main/java/org/springframework/integration/core/MessageSelector.java

@@ -20,10 +20,10 @@ import org.springframework.messaging.Message;
 
 /**
  * Strategy interface for message selection.
- * 
+ *
  * @author Mark Fisher
  */
-public interface MessageSelector {
+public interface MessageSelector extends GenericSelector<Message<?>> {
 
 	boolean accept(Message<?> message);
 

spring-integration-core/src/main/java/org/springframework/integration/transformer/GenericTransformer.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2014 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.transformer;
+
+/**
+ * Generic (lambda) strategy interface for transformer.
+ *
+ * @param <S> the source type - 'transform from'.
+ * @param <T> the target type - 'transform to'.
+ *
+ * @author Artem Bilan
+ * @since 4.0
+ */
+public interface GenericTransformer<S, T> {
+
+	T transform(S source);
+
+}

spring-integration-core/src/main/java/org/springframework/integration/transformer/Transformer.java

@@ -20,10 +20,10 @@ import org.springframework.messaging.Message;
 
 /**
  * Strategy interface for transforming a {@link Message}.
- * 
+ *
  * @author Mark Fisher
  */
-public interface Transformer {
+public interface Transformer extends GenericTransformer<Message<?>, Message<?>> {
 
 	Message<?> transform(Message<?> message);