xletmanager.java

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/*
 * @(#)XletManager.java	1.21 06/10/10
 *
 * Copyright  1990-2008 Sun Microsystems, Inc. All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version
 * 2 only, as published by the Free Software Foundation. 
 * 
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License version 2 for more details (a copy is
 * included at /legal/license.txt). 
 * 
 * You should have received a copy of the GNU General Public License
 * version 2 along with this work; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA 
 * 
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
 * Clara, CA 95054 or visit www.sun.com if you need additional
 * information or have any questions. 
 *
 */

package com.sun.xlet;

import javax.microedition.xlet.*;
import javax.microedition.xlet.ixc.*;
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.Frame;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.IOException;
import java.io.File;
import java.net.URL;
import java.net.MalformedURLException;
import java.lang.reflect.Constructor;
import java.rmi.AccessException;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.security.PrivilegedExceptionAction;
import java.security.PrivilegedActionException;
import java.util.Hashtable;
import java.util.Vector;

import sun.awt.SunToolkit;
import sun.awt.AppContext;

public class XletManager implements XletLifecycleHandler {

    // the root frame shared by all xlets
    static ToplevelFrame theFrame; 
    // list of active <XletContext,XletManager> pairs 
    static Hashtable activeContexts = new Hashtable(); 

    // the xlet class this XletManager instance handles
    private Class xletClass;    
    // this XletManager's state queue
    private XletStateQueue xletQueue; 

    // The instance of the xletClass above.  
    // Both Class and the instance are kept
    // as xlet instantiation calls into the user code,
    // thus should be handled in the XletStateQueue thread,
    // and this thread only knows about local data right now.
    private Xlet xlet;  

    // this Xlet's XletContext
    private XletContextImpl context; 
    // Xlet's current state
    private XletState currentState = XletState.UNLOADED;

    // this Xlet's threadGroup and AppContext
    ThreadGroup threadGroup;  
    AppContext appContext;

    private Object stateGuard = new Object();

    protected XletManager(XletClassLoader xletClassLoader,
                 String mainClass,
                 String[] args) throws ClassNotFoundException {

       xletClass = xletClassLoader.loadClass(mainClass);
         
       if (!(Xlet.class).isAssignableFrom(xletClass)) {
          throw new ClassCastException(
             "Attempt to run a non-Xlet class: " + mainClass);
       }

       context = new XletContextImpl(mainClass, args, this);
       activeContexts.put(context, this);

       final ThreadGroup currentTG = Thread.currentThread().getThreadGroup();
       final int numOfXlets = activeContexts.size();
       final String className = mainClass;
       final ClassLoader finalLoader = xletClassLoader;

       threadGroup = (ThreadGroup) AccessController.doPrivileged(
          new PrivilegedAction() {
             public Object run() {
                return  new ThreadGroup(currentTG, 
                                       "Xlet Thread Group " + numOfXlets);
             }   
          }      
       );
      
       // Create an Xlet state change dispatcher queue
       final XletManager thisXletManager = this;
       xletQueue = (XletStateQueue) AccessController.doPrivileged(
          new PrivilegedAction() {
             public Object run() {
                Thread t = new Thread(threadGroup,
                           new Runnable() {
                              public void run() {
                                 manageLifecycle();
                              }
                           }, "Xlet lifecycle for " + className);
                t.setContextClassLoader(finalLoader);
                t.start();
                return new XletStateQueue(thisXletManager);
             }   
          }      
       );

       // Let the ClassLoader have the reference to this XletManager
       xletClassLoader.setXletManager(this);
       // Register an AppContext with this ThreadGroup.
       // Note: Create AppContext after registering XletManager to XletClassLoader,
       //       as AppContext creation leads to EventQueue dispatcher thread
       //       creation.  ThreadGroup for the new Thread is provided by
       //       the SecurityManager if installed, and XletSecurity needs
       //       XletClassLoader to have a reference of xletManager to get TG.
       createAppContext(threadGroup);

       if (theFrame == null) { // Grab the Frame before xlet gets it's chance.
          theFrame = new ToplevelFrame("Xlet Frame", this); 
       }

       // Install a SecurityManager on this xlet if nothing is set.
       // Note: If this is launching a second xlet, all code above is already
       //       executing with XletSecurity installed.
       installSecurityManager();

       // Finally, request the xlet to be instantiated.
       xletQueue.push(XletState.LOADED);
    }

    /**
     * Call SunToolkit to create a dedicated EventQueue
     * for the caller Xlet.  Guarantees that AppContext 
     * is created by the the the method returns.
     *
     * @param ThreadGroup which the xlet's lifecycle thread
     *        is running within
     */
    final Object syncObject = new Object();
    private void createAppContext(ThreadGroup tg) {
       final ThreadGroup finalTG = tg;
       final ClassLoader finalLoader = getClassLoader();
       AccessController.doPrivileged( 
          new PrivilegedAction() {
             public Object run() {
                Thread t2 = new Thread(finalTG,
                   new Runnable() {
                       public void run() {
                          synchronized (syncObject) {
                              appContext = SunToolkit.createNewAppContext();
                              syncObject.notifyAll();
                          }
                       }
                   }, "AppContext creation thread");
                // Need to set ContextClassLoader, as this thread 
                // is later used as the EventQueue's dispatching thread
                t2.setContextClassLoader(finalLoader);
                synchronized (syncObject) {
                   t2.start();
                   try {
                      syncObject.wait();
                   } catch (InterruptedException e) {}
                }
                return null;
             }
          }
       );
       return;
    }

    /*
     * Install XletSecurity if no SecurityManager is set.
     */
    private void installSecurityManager() {
        if (System.getSecurityManager() == null) {
           System.setSecurityManager(new XletSecurity(appContext));
        }
    }

    public Container getContainer() {
        return theFrame.getXletContainer();
    }

    public void postInitXlet() {
        xletQueue.push(DesiredXletState.INITIALIZE);
    }

    public void postStartXlet() {
        xletQueue.push(XletState.ACTIVE);
    }

    public void postPauseXlet() {
        xletQueue.push(XletState.PAUSED);
    }
 
    public void postDestroyXlet(boolean unconditional) {
        if (!unconditional) {
            xletQueue.push(DesiredXletState.CONDITIONAL_DESTROY);
        } else {
            xletQueue.push(XletState.DESTROYED);
        }
    }

    public void setState(XletState state) { 
        
        if (currentState == XletState.DESTROYED || 
            state == currentState) 
             return;

        synchronized (stateGuard) {
            currentState = state;
            stateGuard.notifyAll();
        }
    }

    public int getState() { 
        XletState state = getXletState();
        if (state == XletState.LOADED) {
            return LOADED;
        } else if (state == XletState.PAUSED) {
            return PAUSED;
        } else if (state == XletState.ACTIVE) {
            return ACTIVE;