org.apache.activemq.broker.region.policy.MessageEvictionStrategy Maven / Gradle / Ivy
/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.activemq.broker.region.policy;
import java.io.IOException;
import java.util.LinkedList;
import org.apache.activemq.broker.region.MessageReference;
/**
* A strategy for evicting messages from slow consumers.
*
*
*/
public interface MessageEvictionStrategy {
/**
* Find the message reference in the given list with oldest messages at the front and newer messages at the end
*
* @return the message that has been evicted.
* @throws IOException if an exception occurs such as reading a message content (but should not ever happen
* as usually all the messages will be in RAM when this method is called).
*/
MessageReference[] evictMessages(LinkedList messages) throws IOException;
/**
* REturns the high water mark on which we will eagerly evict expired messages from RAM
*/
int getEvictExpiredMessagesHighWatermark();
}