pipeserviceprotocol.java

来自「This is a resource based on j2me embedde」· Java 代码 · 共 412 行 · 第 1/2 页

/*
 *
 *
 * 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.midp.io.j2me.pipe.serviceProtocol;

import com.sun.cldc.isolate.Isolate;
import com.sun.midp.links.Link;
import com.sun.midp.links.LinkMessage;
import com.sun.midp.security.SecurityToken;
import com.sun.midp.services.SystemServiceConnection;
import com.sun.midp.services.SystemServiceConnectionClosedException;
import com.sun.midp.services.SystemServiceDataMessage;
import com.sun.midp.services.SystemServiceLinkMessage;
import com.sun.midp.services.SystemServiceManager;
import com.sun.midp.services.SystemServiceMessage;
import com.sun.midp.services.SystemServiceRequestor;
import java.io.ByteArrayInputStream;
import java.io.DataInput;
import java.io.DataInputStream;
import java.io.DataOutput;
import java.io.IOException;
import java.io.InterruptedIOException;
import javax.microedition.io.ConnectionNotFoundException;

/**
 * Implementation of low-level inter-isolate protocol to manage Pipes.
 * Both AMS-side and client-side code is provided by this class
 * to minimize chance of making protocol out-of-sync.
 */
public class PipeServiceProtocol {

    static final String SERVICE_ID = "com.sun.midp.io.pipe";
    static final int MAGIC_BIND_PIPE_SERVER = 0x49587001;
    static final int MAGIC_BIND_PIPE_CLIENT = 0x49587002;
    static final int MAGIC_CLOSE_PIPE_SERVER = 0x49587003;
    static final int MAGIC_ACCEPT_PIPE_SERVER = 0x49587004;
    static final int MAGIC_OK = 0x49587011;
    static final int MAGIC_FAIL = 0x49587012;
    static final int MAGIC_WOULDBLOCK = 0x49587013;
    private static final boolean DEBUG = false;
    private static long nextEndpointIdToIssue;
    private int debugInstanceId;
    private static int nextDebugInstanceId;
    private SecurityToken token;
    private String serverName;
    private String serverVersionRequested;
    private String serverVersionActual;
    private Link inboundLink;
    private Link outboundLink;
    private static SystemServiceConnection serviceConn;         // connection to/from pipe service
    private static final Object serviceConnLock = new Object(); // lock which guards serviceConn
    private long serverInstanceId;
    private Link acceptLink;
    private final Object acceptLock = new Object();             // guards method accept()

    private PipeServiceProtocol(SecurityToken token) {
        this.token = token;
        debugInstanceId = nextDebugInstanceId++;
    }

    /**
     * On the side of user task (i.e. in MIDlet's execusion context) obtains protocol instance
     * connected to pipe service. Shall not be used on side of service task.
     *
     * @param token priviledged instance of SecurityToken
     * @return instance of PipeServiceProtocol properly initialized to be able to communicate
     * to pipe service
     */
    public static synchronized PipeServiceProtocol getService(SecurityToken token) {
        if (serviceConn == null) {
            SystemServiceRequestor serviceRequestor =
                    SystemServiceRequestor.getInstance(token);
            serviceConn = serviceRequestor.requestService(SERVICE_ID);
            if (serviceConn == null) {
                if (DEBUG)
                    debugPrintS(" ERR: service not found");
                throw new IllegalStateException("Pipe service not found");
            }
        }

        PipeServiceProtocol service = new PipeServiceProtocol(token);

        return service;
    }

    /**
     * Registers pipe service with System Service API. To be used only in context of service task
     * (e.g. AMS Isolate).
     *
     * @param token priviledged instance of SecurityToken
     */
    public static void registerService(SecurityToken token) {
        Dispatcher dispatcher = new Dispatcher(token);
        SystemServiceManager manager = SystemServiceManager.getInstance(token);
        manager.registerService(dispatcher);
        if (DEBUG)
            debugPrintS(" service registered");
    }

    /**
     * Binds given task as pipe client and tries to establish pipe connection.
     * Parameters provided are used by pipe service to search for
     * appropriate pipe server connection. If appopriate server it's connected with data Links so
     * {@link #getInboundLink()} and {@link #getOutboundLink()} to be used to fetch them.
     *
     * @param serverName name of pipe server to search for
     * @param serverVersionRequested version of the server to search for
     * @throws java.io.IOException if requested server cannot be found (i.e. connection not found) or
     * there is some problem commnucating with pipe service.
     */
    public void bindClient(String serverName, String serverVersionRequested)
            throws IOException {
        if (DEBUG)
            debugPrint(" connectClient " + serverName + ' ' + serverVersionRequested);
        synchronized (serviceConnLock) {
            try {
                SystemServiceDataMessage msg = SystemServiceMessage.newDataMessage();
                DataOutput out = msg.getDataOutput();
                out.writeInt(MAGIC_BIND_PIPE_CLIENT);
                out.writeUTF(serverName);
                out.writeUTF(serverVersionRequested);
                out.writeLong(Isolate.currentIsolate().uniqueId());
                serviceConn.send(msg);

                msg = (SystemServiceDataMessage) serviceConn.receive();
                DataInput in = msg.getDataInput();
                int result = in.readInt();
                if (result != MAGIC_OK) {
                    throw new ConnectionNotFoundException(in.readUTF());
                }
                serverVersionActual = in.readUTF();

                this.serverName = serverName;
                this.serverVersionRequested = serverVersionRequested;
                SystemServiceLinkMessage linkMsg = (SystemServiceLinkMessage) serviceConn.receive();
                inboundLink = linkMsg.getLink();
                linkMsg = (SystemServiceLinkMessage) serviceConn.receive();
                outboundLink = linkMsg.getLink();
            } catch (SystemServiceConnectionClosedException cause) {
                if (DEBUG) {
                    debugPrint(" ERR:");
                    cause.printStackTrace();
                }
                throw new IOException("Cannot communicate with pipe service: " + cause);
            }
        }
        if (DEBUG)
            debugPrint(" connectClient " + serverName + ' ' + serverVersionRequested + " completed");
    }

    /**
     * Binds given task as pipe server and registers server within pipe service.
     *
     * @param serverName name of the server to register
     * @param serverVersion version of the server to register
     * @throws java.io.IOException if server cannot be bound with pipe service
     */
    public void bindServer(String serverName, String serverVersion)
            throws IOException {
        if (DEBUG)
            debugPrint(" connectServer " + serverName + ' ' + serverVersion);
        synchronized (serviceConnLock) {
            try {
                SystemServiceDataMessage msg = SystemServiceMessage.newDataMessage();
                DataOutput out = msg.getDataOutput();
                out.writeInt(MAGIC_BIND_PIPE_SERVER);
                out.writeUTF(serverName);
                out.writeUTF(serverVersion);
                out.writeLong(Isolate.currentIsolate().uniqueId());
                serviceConn.send(msg);

                msg = (SystemServiceDataMessage) serviceConn.receive();
                DataInput in = msg.getDataInput();
                int result = in.readInt();
                if (result != MAGIC_OK) {
                    throw new ConnectionNotFoundException(in.readUTF());
                }
                serverInstanceId = in.readLong();

                this.serverName = serverName;
                this.serverVersionActual = serverVersion;
            } catch (SystemServiceConnectionClosedException cause) {
                if (DEBUG) {
                    debugPrint(" ERR:");