Added AbstractConsumerFactoryBean and SplitterFactoryBean to support different consumer types that can only be initialized after the "ref" Object's type is known (for example, see INT-397).

org.springframework.integration/src/main/java/org/springframework/integration/config/AbstractConsumerFactoryBean.java

@@ -0,0 +1,95 @@
+/*
+ * Copyright 2002-2008 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.config;
+
+import org.springframework.beans.factory.FactoryBean;
+import org.springframework.integration.channel.MessageChannel;
+import org.springframework.integration.endpoint.AbstractReplyProducingMessageConsumer;
+import org.springframework.integration.message.MessageConsumer;
+import org.springframework.util.Assert;
+
+/**
+ * Base class for FactoryBeans that create MessageConsumer instances.
+ * 
+ * @author Mark Fisher
+ */
+public abstract class AbstractConsumerFactoryBean implements FactoryBean {
+
+	private volatile MessageConsumer consumer;
+
+	private volatile Object targetObject;
+
+	private volatile String targetMethodName;
+
+	private volatile MessageChannel outputChannel;
+
+	private volatile boolean initialized;
+
+	private final Object initializationMonitor = new Object();
+
+
+	public void setTargetObject(Object targetObject) {
+		this.targetObject = targetObject;
+	}
+
+	public void setTargetMethodName(String targetMethodName) {
+		this.targetMethodName = targetMethodName;
+	}
+
+	public void setOutputChannel(MessageChannel outputChannel) {
+		this.outputChannel = outputChannel;
+	}
+
+	public Object getObject() throws Exception {
+		if (this.consumer == null) {
+			this.initializeConsumer();
+			Assert.notNull(this.consumer, "failed to create MessageConsumer");
+			if (this.outputChannel != null
+					&& this.consumer instanceof AbstractReplyProducingMessageConsumer) {
+				((AbstractReplyProducingMessageConsumer) this.consumer).setOutputChannel(this.outputChannel);
+			}
+		}
+		return this.consumer;
+	}
+
+	public Class<?> getObjectType() {
+		if (this.consumer != null) {
+			return this.consumer.getClass();
+		}
+		return MessageConsumer.class;
+	}
+
+	public boolean isSingleton() {
+		return true;
+	}
+
+	private void initializeConsumer() {
+		synchronized (this.initializationMonitor) {
+			if (this.initialized) {
+				return;
+			}
+			this.consumer = this.createConsumer(this.targetObject, this.targetMethodName);
+			this.initialized = true;
+		}
+	}
+
+	/**
+	 * Subclasses must implement this method to create the MessageConsumer.
+	 */
+	protected abstract MessageConsumer createConsumer(Object targetObject, String targetMethodName);
+
+}

org.springframework.integration/src/main/java/org/springframework/integration/config/SplitterFactoryBean.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2002-2008 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.config;
+
+import org.springframework.integration.message.MessageConsumer;
+import org.springframework.integration.splitter.AbstractMessageSplitter;
+import org.springframework.integration.splitter.DefaultMessageSplitter;
+import org.springframework.integration.splitter.MethodInvokingSplitter;
+import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
+
+/**
+ * Factory bean for creating a Message Splitter.
+ * 
+ * @author Mark Fisher
+ */
+public class SplitterFactoryBean extends AbstractConsumerFactoryBean {
+
+	@Override
+	protected MessageConsumer createConsumer(Object targetObject, String targetMethodName) {
+		if (targetObject == null) {
+			Assert.isTrue(!StringUtils.hasText(targetMethodName),
+					"'method' should only be provided when 'ref' is also provided");
+			return new DefaultMessageSplitter();
+		}
+		if (targetObject instanceof AbstractMessageSplitter) {
+			return (AbstractMessageSplitter) targetObject;
+		}
+		return (StringUtils.hasText(targetMethodName))
+				? new MethodInvokingSplitter(targetObject, targetMethodName)
+				: new MethodInvokingSplitter(targetObject);
+	}
+
+}

org.springframework.integration/src/main/java/org/springframework/integration/config/SplitterParser.java

@@ -20,8 +20,6 @@ import org.w3c.dom.Element;
 
 import org.springframework.beans.factory.support.BeanDefinitionBuilder;
 import org.springframework.beans.factory.xml.ParserContext;
-import org.springframework.integration.splitter.DefaultMessageSplitter;
-import org.springframework.integration.splitter.MethodInvokingSplitter;
 import org.springframework.util.StringUtils;
 
 /**
@@ -33,17 +31,16 @@ public class SplitterParser extends AbstractConsumerEndpointParser {
 
 	@Override
 	protected BeanDefinitionBuilder parseConsumer(Element element, ParserContext parserContext) {
+		BeanDefinitionBuilder builder = BeanDefinitionBuilder.genericBeanDefinition(SplitterFactoryBean.class);
 		if (element.hasAttribute(REF_ATTRIBUTE)) {
 			String ref = element.getAttribute(REF_ATTRIBUTE);
-			BeanDefinitionBuilder builder = BeanDefinitionBuilder.genericBeanDefinition(MethodInvokingSplitter.class);
-			builder.addConstructorArgReference(ref);
+			builder.addPropertyReference("targetObject", ref);
 			if (StringUtils.hasText(element.getAttribute(METHOD_ATTRIBUTE))) {
 				String method = element.getAttribute(METHOD_ATTRIBUTE);
-				builder.addConstructorArgValue(method);
+				builder.addPropertyValue("targetMethodName", method);
 			}
-			return builder;
 		}
-		return BeanDefinitionBuilder.genericBeanDefinition(DefaultMessageSplitter.class);
+		return builder;
 	}
 
 }