startlevelimpl.java

OSGI 的 源码实现,采用JAVA书写

/*
 * Oscar - An implementation of the OSGi framework.
 * Copyright (c) 2004, Richard S. Hall
 * All rights reserved.
 *  
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *  
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in
 *     the documentation and/or other materials provided with the
 *     distribution.
 *   * Neither the name of the ungoverned.org nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *  
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * 
 * Contact: Richard S. Hall ([e-mail])
 * Contributor(s):
 * 
**/
package org.ungoverned.oscar;

import java.security.AccessController;
import java.util.ArrayList;
import java.util.List;

import org.osgi.framework.AdminPermission;
import org.osgi.framework.Bundle;
import org.osgi.service.startlevel.StartLevel;

/**
 * @author rickhall
 *
 * To change the template for this generated type comment go to
 * Window>Preferences>Java>Code Generation>Code and Comments
**/
public class StartLevelImpl implements StartLevel, Runnable
{
    private Oscar m_oscar = null;
    private List m_requestList = null;
    // Reusable admin permission.
    private static AdminPermission m_adminPerm = new AdminPermission();
    
    public StartLevelImpl(Oscar oscar)
    {
        m_oscar = oscar;
        m_requestList = new ArrayList();

        // Start a thread to perform asynchronous package refreshes.
        Thread t = new Thread(this, "OscarStartLevel");
        t.setDaemon(true);
        t.start();
    }
    
    /* (non-Javadoc)
     * @see org.osgi.service.startlevel.StartLevel#getStartLevel()
    **/
    public int getStartLevel()
    {
        return m_oscar.getStartLevel();
    }

    /* (non-Javadoc)
     * @see org.osgi.service.startlevel.StartLevel#setStartLevel(int)
    **/
    public void setStartLevel(int startlevel)
    {
        if (System.getSecurityManager() != null)
        {
            AccessController.checkPermission(m_adminPerm);
        }
        else if (startlevel <= 0)
        {
            throw new IllegalArgumentException(
                "Start level must be greater than zero.");
        }
        synchronized (m_requestList)
        {
            m_requestList.add(new Integer(startlevel));
            m_requestList.notifyAll();
        }
    }

    /* (non-Javadoc)
     * @see org.osgi.service.startlevel.StartLevel#getBundleStartLevel(org.osgi.framework.Bundle)
    **/
    public int getBundleStartLevel(Bundle bundle)
    {
        return m_oscar.getBundleStartLevel(bundle);
    }

    /* (non-Javadoc)
     * @see org.osgi.service.startlevel.StartLevel#setBundleStartLevel(org.osgi.framework.Bundle, int)
    **/
    public void setBundleStartLevel(Bundle bundle, int startlevel)
    {
        m_oscar.setBundleStartLevel(bundle, startlevel);
    }

    /* (non-Javadoc)
     * @see org.osgi.service.startlevel.StartLevel#getInitialBundleStartLevel()
    **/
    public int getInitialBundleStartLevel()
    {
        return m_oscar.getInitialBundleStartLevel();
    }

    /* (non-Javadoc)
     * @see org.osgi.service.startlevel.StartLevel#setInitialBundleStartLevel(int)
    **/
    public void setInitialBundleStartLevel(int startlevel)
    {
        m_oscar.setInitialBundleStartLevel(startlevel);
    }

    /* (non-Javadoc)
     * @see org.osgi.service.startlevel.StartLevel#isBundlePersistentlyStarted(org.osgi.framework.Bundle)
    **/
    public boolean isBundlePersistentlyStarted(Bundle bundle)
    {
        return m_oscar.isBundlePersistentlyStarted(bundle);
    }

    public void run()
    {
        int startLevel = 0;

        // This thread loops forever, thus it should
        // be a daemon thread.
        while (true)
        {
            synchronized (m_requestList)
            {
                // Wait for a request.
                while (m_requestList.size() == 0)
                {
                    try {
                        m_requestList.wait();
                    } catch (InterruptedException ex) {
                    }
                }
                
                // Get the requested start level.
                startLevel = ((Integer) m_requestList.remove(0)).intValue();
            }

            // Set the new start level.
            m_oscar.setStartLevelInternal(startLevel);
        }
    }
}