/*
* 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.aggregator;
import org.springframework.integration.core.Message;
import org.springframework.integration.core.MessagingException;
import org.springframework.integration.util.DefaultMethodInvoker;
import org.springframework.util.Assert;
import org.springframework.util.ReflectionUtils;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
/**
* Base class for implementing adapters for methods which take as an argument a
* list of {@link Message Message} instances or payloads.
*
* @author Marius Bogoevici
*/
public class MessageListMethodAdapter {
private final DefaultMethodInvoker invoker;
protected final Method method;
public MessageListMethodAdapter(Object object, String methodName) {
Assert.notNull(object, "'object' must not be null");
Assert.notNull(methodName, "'methodName' must not be null");
this.method = ReflectionUtils.findMethod(object.getClass(), methodName, new Class<?>[]{List.class});
Assert.notNull(this.method, "Method '" + methodName +
"(List<?> args)' not found on '" + object.getClass().getName() + "'.");
this.invoker = new DefaultMethodInvoker(object, this.method);
}
public MessageListMethodAdapter(Object object, Method method) {
Assert.notNull(object, "'object' must not be null");
Assert.notNull(method, "'method' must not be null");
Assert.isTrue(method.getParameterTypes().length == 1
&& method.getParameterTypes()[0].equals(List.class),
"Method " + method + " does not accept exactly one parameter, of type List.");
this.method = method;
this.invoker = new DefaultMethodInvoker(object, this.method);
}
protected Method getMethod() {
return method;
}
private static boolean isActualTypeParameterizedMessage(Method method) {
return (getCollectionActualType(method) instanceof ParameterizedType)
&& Message.class.isAssignableFrom((Class<?>) ((ParameterizedType) getCollectionActualType(method)).getRawType());
}
protected final Object executeMethod(Collection<Message<?>> messages) {
try {
if (isMethodParameterParameterized(this.method) && isHavingActualTypeArguments(this.method)
&& (isActualTypeRawMessage(this.method) || isActualTypeParameterizedMessage(this.method))) {
return this.invoker.invokeMethod(messages);
}
return this.invoker.invokeMethod(extractPayloadsFromMessages(messages));
}
catch (InvocationTargetException e) {
throw new MessagingException(
"Method '" + this.method + "' threw an Exception.", e.getTargetException());
}
catch (Exception e) {
throw new MessagingException("Failed to invoke method '" + this.method + "'.");
}
}
private List<?> extractPayloadsFromMessages(Collection<Message<?>> messages) {
List<Object> payloadList = new ArrayList<Object>();
for (Message<?> message : messages) {
payloadList.add(message.getPayload());
}
return payloadList;
}
private static boolean isActualTypeRawMessage(Method method) {
return getCollectionActualType(method).equals(Message.class);
}
private static Type getCollectionActualType(Method method) {
return ((ParameterizedType) method.getGenericParameterTypes()[0]).getActualTypeArguments()[0];
}
private static boolean isHavingActualTypeArguments(Method method) {
return ((ParameterizedType) method.getGenericParameterTypes()[0]).getActualTypeArguments().length == 1;
}
private static boolean isMethodParameterParameterized(Method method) {
return method.getGenericParameterTypes().length == 1
&& method.getGenericParameterTypes()[0] instanceof ParameterizedType;
}
}
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