activemq-broker/src/main/java/org/apache/activemq/store/IndexListener.java

/**
 * 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.store;

import org.apache.activemq.broker.ConnectionContext;
import org.apache.activemq.command.Message;

/**
 * callback when the index is updated, allows ordered work to be seen by destinations
 */
public interface IndexListener {

    final class MessageContext {
        public final Message message;
        public final ConnectionContext context;
        public final Runnable onCompletion;
        public boolean duplicate;

        public MessageContext(ConnectionContext context, Message message, Runnable onCompletion) {
            this.context = context;
            this.message = message;
            this.onCompletion = onCompletion;
        }
    }

    /**
     *  called with some global index lock held so that a listener can do order
     *  dependent work
     *  non null MessageContext.onCompletion called when work is done
     */
    public void onAdd(MessageContext messageContext);

}