midletpeer.java

来自「This is a resource based on j2me embedde」· Java 代码 · 共 499 行 · 第 1/2 页

/*
 *
 *
 * Copyright  1990-2007 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.midp.midlet;

import javax.microedition.io.ConnectionNotFoundException;

import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;

import com.sun.midp.security.Permissions;
import com.sun.midp.security.SecurityToken;


/**
 * MIDletPeer maintains the current state of the MIDlet and forwards updates
 * to it.  It contains a reference to the MIDlet itself.
 * Control methods (startApp, destroyApp,
 * pauseApp) defined here are invoked on the MIDlet object via the
 * MIDletTunnel.
 * <p>
 * All state changes are synchronized using midletStateHandler retrieved
 * from the MIDletStateHandler.
 * NotifyPaused, ResumeRequest, and NotifyDestroyed methods invoked on the
 * MIDlet cause the appropriate state change.  The MIDletStateHandler is aware
 * of changes by waiting on the midletStateHandler.
 */

public class MIDletPeer implements MIDletEventConsumer {
    /*
     * Implementation state; the states are in priority order.
     * That is, a higher number indicates a preference to be
     * selected for activating sooner.  This allows the MIDlet state handler
     * to make one pass over the known MIDlets and pick the
     * "best" MIDlet to activate.
     */

    /**
     * State of the MIDlet is Paused; it should be quiescent
     */
    public static final int PAUSED = 0;

    /**
     * State of the MIDlet is Active
     */
    public static final int ACTIVE = 1;

    /**
     * State of the MIDlet when resumed by the AMS
     */
    static final int ACTIVE_PENDING = 2;

    /**
     * State of the MIDlet when paused by the AMS
     */
    static final int PAUSE_PENDING = 3;

    /**
     * State of the MIDlet with destroy pending
     */
    static final int DESTROY_PENDING = 4;

    /**
     * State of the MIDlet is Destroyed
     */
    public static final int DESTROYED = 5;

    /** The controller of MIDlets. */
    private static MIDletStateHandler midletStateHandler;

    /** The call when a MIDlet's state changes. */
    private static MIDletStateListener midletStateListener;

    /** Handles platform requests. */
    private static PlatformRequest platformRequest;

    /** The MIDletTunnel implementation from javax.microedition.midlet */
    private static MIDletTunnel tunnel;

    /**
     * Initialize the MIDletPeer class. Should only be called by the
     * MIDletPeerList (MIDletStateHandler).
     *
     * @param theMIDletStateHandler the midlet state handler
     * @param theMIDletStateListener the midlet state listener
     * @param thePlatformRequestHandler the platform request handler
     */
    static void initClass(
        MIDletStateHandler theMIDletStateHandler,
        MIDletStateListener theMIDletStateListener,
        PlatformRequest thePlatformRequestHandler) {

        midletStateHandler = theMIDletStateHandler;
        midletStateListener = theMIDletStateListener;
        platformRequest = thePlatformRequestHandler;
    }

    /**
     * Sets up the reference to the MIDletTunnel implementation.
     * This must be called exactly once during system initialization.
     *
     * @param token security token for authorizing the caller
     * @param t the MIDletTunnel implementation
     */
    public static void setMIDletTunnel(SecurityToken token, MIDletTunnel t) {
        token.checkIfPermissionAllowed(Permissions.MIDP);

        tunnel = t;
    }

    /**
     * Returns the MIDletPeer object corresponding to the given
     * midlet instance.
     *
     * @param m the midlet instance
     *
     * @return MIDletPeer instance associate with m
     */
    static MIDletPeer getMIDletPeer(MIDlet m) {
        return tunnel.getMIDletPeer(m);
    }

    /**
     * The applications current state.
     */
    private int state;

    /**
     * The MIDlet for which this is the state.
     */
    protected MIDlet midlet;

    /**
     * Creates a MIDlet's peer which is registered the MIDletStateHandler.
     * Shall be called only from MIDletStateHandler.
     * <p>
     * The peer MIDlet field is set later when the MIDlet's constructor calls
     * newMidletState.
     */
    MIDletPeer() {
        state = ACTIVE_PENDING;        // So it will be made active soon
    }

    /**
     * Get the MIDlet for which this holds the state.
     *
     * @return the MIDlet; will not be null.
     */
    public MIDlet getMIDlet() {
        return midlet;
    }

    /**
     * Forwards startApp to the MIDlet.
     *
     * @exception <code>MIDletStateChangeException</code>  is thrown if the
     *                <code>MIDlet</code> cannot start now but might be able
     *                to start at a later time.
     */
    void startApp() throws MIDletStateChangeException {
        tunnel.callStartApp(midlet);
    }

    /**
     * Forwards pauseApp to the MIDlet.
     *
     */
    void pauseApp() {
        tunnel.callPauseApp(midlet);
    }

    /**
     * Forwards destoryApp to the MIDlet.
     *
     * @param unconditional the flag to pass to destroy
     *
     * @exception <code>MIDletStateChangeException</code> is thrown
     *                if the <code>MIDlet</code>
     *          wishes to continue to execute (Not enter the <i>Destroyed</i>
     *          state).
     *          This exception is ignored if <code>unconditional</code>
     *          is equal to <code>true</code>.
     */
    void destroyApp(boolean unconditional)
        throws MIDletStateChangeException {
        tunnel.callDestroyApp(midlet, unconditional);
    }

    /**
     *
     * Used by a <code>MIDlet</code> to notify the application management
     * software that it has entered into the
     * <i>DESTROYED</i> state.  The application management software will not
     * call the MIDlet's <code>destroyApp</code> method, and all resources
     * held by the <code>MIDlet</code> will be considered eligible for
     * reclamation.
     * The <code>MIDlet</code> must have performed the same operations
     * (clean up, releasing of resources etc.) it would have if the
     * <code>MIDlet.destroyApp()</code> had been called.
     *
     */
    public final void notifyDestroyed() {
        synchronized (midletStateHandler) {
            state = DESTROYED;
            midletStateHandler.notify();
        }
    }

    /**
     * Used by a <code>MIDlet</code> to notify the application management
     * software that it has entered into the <i>PAUSED</i> state.
     * Invoking this method will
     * have no effect if the <code>MIDlet</code> is destroyed,
     * or if it has not yet been started. <p>
     * It may be invoked by the <code>MIDlet</code> when it is in the
     * <i>ACTIVE</i> state. <p>
     *
     * If a <code>MIDlet</code> calls <code>notifyPaused()</code>, in the
     * future its <code>startApp()</code> method may be called make
     * it active again, or its <code>destroyApp()</code> method may be
     * called to request it to destroy itself.
     */
    public final void notifyPaused() {
        int oldState;

        synchronized (midletStateHandler) {
            oldState = state;