org.apache.felix.eventadmin/src/main/java/org/apache/felix/eventadmin/impl/tasks/BlockTask.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.tasks;

/**
 * This task will can be used to block a thread that subsequently will be unblocked 
 * once the task is executed.
 * 
 * @author <a href="mailto:felix-dev@incubator.apache.org">Felix Project Team</a>
 */
public class BlockTask implements HandlerTask
{
    // The internal lock for this object used instead synchronized(this)
    private final Object m_lock = new Object();

    // Has this task not been executed?
    private boolean m_blocking = true;

    /**
     * Unblock possibly blocking threads.
     * 
     * @see org.apache.felix.eventadmin.impl.tasks.HandlerTask#execute()
     */
    public void execute()
    {
        synchronized (m_lock)
        {
            m_blocking = false;
            m_lock.notifyAll();
        }
    }

    /**
     * This methods does nothing since we only need this task to block and unblock
     * threads.
     * 
     * @see org.apache.felix.eventadmin.impl.tasks.HandlerTask#blackListHandler()
     */
    public void blackListHandler()
    {
        // This method does nothing since we only need this task to block and 
        // unblock threads
    }

    /**
     * Block the calling thread until this task is executed.
     */
    public void block()
    {
        synchronized (m_lock)
        {
            while (m_blocking)
            {
                try
                {
                    m_lock.wait();
                } catch (InterruptedException e)
                {

                }
            }
        }
    }

}