/*
* Copyright 2002-2016 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.aggregator;
import org.springframework.integration.store.MessageGroup;
/**
* A {@link ReleaseStrategy} that releases only the first <code>n</code> messages, where <code>n</code> is a threshold.
*
* @author Dave Syer
* @author Oleg Zhurakousky
*
*/
public class MessageCountReleaseStrategy implements ReleaseStrategy {
private final int threshold;
/**
* @param threshold the number of messages to accept before releasing
*/
public MessageCountReleaseStrategy(int threshold) {
super();
this.threshold = threshold;
}
/**
* Convenient constructor is only one message is required (threshold=1).
*/
public MessageCountReleaseStrategy() {
this(1);
}
/**
* Release the group if it has more messages than the threshold and has not previously been released.
* It is possible that more messages than the threshold could be released, but only if multiple consumers
* receive messages from the same group concurrently.
*/
@Override
public boolean canRelease(MessageGroup group) {
return group.size() >= this.threshold;
}
}