org.apache.felix.eventadmin/src/main/java/org/apache/felix/eventadmin/impl/dispatch/TaskQueue.java

/*
 *   Copyright 2005 The Apache Software Foundation
 *
 *   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.apache.felix.eventadmin.impl.dispatch;

import org.apache.felix.eventadmin.impl.tasks.HandlerTask;

/**
 * This is the interface for a simple queue that allows to append or push arrays
 * of tasks to it. The elements of such an array are added atomically (i.e, they
 * are in the same order one after the other in the queue) either at the end or the
 * front of the queue. Additionally, the queue can be closed. 
 * 
 * @author <a href="mailto:felix-dev@incubator.apache.org">Felix Project Team</a>
 */
public interface TaskQueue
{
    /**
     * Append the tasks to this queue in one atomic operation while preserving their
     * order.
     * 
     * @param tasks The tasks to append to this queue
     * 
     * @throws IllegalStateException in case that this queue is already closed
     */
    public void append(HandlerTask[] tasks);
    
    /**
     * Push the tasks to this queue in one atomic operation while preserving their
     * order.  
     * 
     * @param tasks The tasks to push to the front of this queue.
     * 
     * @throws IllegalStateException in case that this queue is already closed
     */
    public void push(HandlerTask[] tasks);
    
    /**
     * Close the queue. 
     */
    public void close();
}