shellapp.java

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/*
 * Copyright (c) 2001 Sun Microsystems, Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. 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.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *       Sun Microsystems, Inc. for Project JXTA."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Sun", "Sun Microsystems, Inc.", "JXTA" and "Project JXTA" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact Project JXTA at http://www.jxta.org.
 *
 * 5. Products derived from this software may not be called "JXTA",
 *    nor may "JXTA" appear in their name, without prior written
 *    permission of Sun.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 SUN MICROSYSTEMS OR
 * ITS 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of Project JXTA.  For more
 * information on Project JXTA, please see
 * <http://www.jxta.org/>.
 *
 * This license is based on the BSD license adopted by the Apache Foundation.
 *
 * $Id: ShellApp.java,v 1.42 2004/06/12 21:34:02 bondolo Exp $
 */


package net.jxta.impl.shell;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.io.Reader;
import java.io.StringWriter;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import java.io.IOException;

import net.jxta.peergroup.PeerGroup;
import net.jxta.pipe.InputPipe;
import net.jxta.pipe.OutputPipe;
import net.jxta.platform.Application;
import net.jxta.document.Advertisement;
import net.jxta.endpoint.Message;
import net.jxta.endpoint.MessageElement;
import net.jxta.endpoint.StringMessageElement;
import net.jxta.endpoint.TextMessageElement;
import net.jxta.id.ID;

/**
 * This class is the base class any JXTA Shell application must extend.
 */
public abstract class ShellApp implements Application {
    
    /**
     *  The command is still running.
     */
    public final static int appSpawned = -1;
    
    /**
     *  The command completed successfully.
     */
    public final static int appNoError = 0;
    
    /**
     *  An error occurred resulting from incorrect or missing parameters.
     */
    public final static int appParamError = 1;
    
    /**
     * Something bad happened. Don't know what it means, don't care why it
     * happened.
     */
    public final static int appMiscError = Integer.MAX_VALUE;
    
    /**
     *  The default peergroup associated with this app.
     **/
    private PeerGroup group = null;
    
    /**
     *  The assigned id for this application, if any.
     **/
    private ID id = null;
    
    /**
     *  The implementation advertisement for this application, if any.
     **/
    private Advertisement implAdv = null;
    
    /**
     *  The environment for this application. Copied from the host shell.
     **/
    private ShellEnv env = null;
    
    /**
     *  The "stdin" input pipe for this command.
     **/
    private InputPipe inputPipe = null;
    
    /**
     *  The "stdout" output pipe for this command.
     **/
    private OutputPipe outputPipe = null;
    
    /**
     *  The console input. Differs from the stdin if stdin has been
     *  redirected. consin is not normally redirected.
     **/
    private InputPipe consin = null;
    
    /**
     *  The console output. Differs from the stdout if stdout has been
     *  redirected. consout is not normally redirected.
     **/
    private OutputPipe  consout = null;
    
    /**
     *  if the result is a shell object then store it using this name.
     **/
    private String returnVarName = null;
    
    /**
     *  Has this app begun running?
     **/
    protected volatile boolean started = false;
    
    /**
     *  Has this app in the process of quitting?
     **/
    protected volatile boolean stopped = false;
    
    /**
     *  If this thread is enabled, then this is the root thread of another
     *  command which this command can use to determine when it should finish.
     **/
    private Thread dependsOn = null;
    
    /**
     *  private buffer for input pipe
     **/
    private List buffered = new ArrayList();
    
    /**
     *  private buffer for console input pipe.
     **/
    private List consbuffer = new ArrayList();
    
    /**
     *  {@inheritDoc}
     **/
    public final void init(PeerGroup pg, ID assignedID, Advertisement impl) {
        setGroup(pg);
        setAssignedID(assignedID);
        setImplAdvertisement(impl);
        
        started  = true;
    }
    
    /**
     *  {@inheritDoc}
     **/
    public void stopApp() {
        stopped = true;
    }
    
    /**
     *  Return a String containting a single line description of the function of
     *  this ShellApp.
     **/
    public String getDescription() {
        return "No description available for this ShellApp";
    }
    
    /**
     *  Print to the stdout a full description of the functionality of this
     *  Shell command.
     **/
    public void help() {
        println("No help available for this ShellApp");
    }
    
    // Accessor Methods
    
    /**
     *  Return the group in which this ShellApp is executing. Most ShellApps
     *  should instead use the value of the "stdgroup" enviroment variable.
     *
     *  @return the current peer group.
     **/
    protected PeerGroup getGroup() {
        return group;
    }
    
    /**
     *  Set the group will be the default group for this ShellApp. Most ShellApps
     *  should instead use the value of the "stdgroup" enviroment variable.
     **/
    private final PeerGroup setGroup(PeerGroup g) {
        PeerGroup old = group;
        group = g;
        return old;
    }
    
    /**
     *  Return the assignedID for this ShellApp if any.
     *
     *  @return the assigned ID for this ShellApp or <code>null</code> if none
     *  was specified.
     **/
    protected final ID getAssignedID() {
        return this.id;
    }
    
    
    /**
     *  Set the assignedID for this ShellApp
     *
     *  @param id   The assigned ID for this application
     **/
    private final void setAssignedID(ID id) {
        this.id = id;
    }
    
    /**
     *  Return the implementation advertisement for this ShellApp, if any.
     *
     *  @return implementation Advertisement for this ShellApp or <code>null</code>
     *  if none was specified.
     **/
    protected final Advertisement getImplAdvertisement() {
        return this.implAdv;
    }
    
    /**
     *  Sets the implementation advertisement for this ShellApp.
     *
     *  @param adv The implementation advertisement for this ShellApp.
     **/
    private final Advertisement setImplAdvertisement(Advertisement adv) {
        Advertisement old = this.implAdv;
        this.implAdv = adv;
        return old;
    }
    
    /**
     *  Return a modifiable instance of this ShellApp's environment.
     *
     *  @return This ShellApp's environment.
     **/
    protected final ShellEnv getEnv() {
        return env;
    }
    
    /**
     *  Sets this ShellApp's environment.
     *
     *  @return The environment for this ShellApp to use.
     **/
    protected final ShellEnv setEnv(ShellEnv e) {
        ShellEnv old = env;
        env = e;
        return old;
    }
    
    protected final Thread setJoinedThread(Thread dependsOn) {
        Thread old = this.dependsOn;
        this.dependsOn = dependsOn;
        return old;
    }
    
    /**
     *  Return the standard input pipe.
     *
     *  @return the standard input pipe.
     **/
    protected final InputPipe getInputPipe() {
        return inputPipe;
    }
    
    /**
     *  Set the standard input pipe to the provided pipe. The previous pipe is
     *  returned.
     *
     *  @param ip the new standard input pipe.
     *  @return the old standard input pipe.
     **/
    protected final InputPipe setInputPipe(InputPipe ip) {
        InputPipe old = inputPipe;
        
        inputPipe = ip;
        
        buffered.clear();
        
        return old;
    }
    
    /**
     *  Return the standard output pipe.
     *
     *  @return the standard output pipe.
     **/
    protected final OutputPipe getOutputPipe() {
        return outputPipe;
    }
    
    /**
     *  Set the standard output pipe to the provided pipe. The previous pipe is
     *  returned.
     *
     *  @param op the new standard output pipe.
     *  @return the old standard output pipe.
     **/
    protected final OutputPipe setOutputPipe(OutputPipe op) {
        OutputPipe old = outputPipe;
        outputPipe = op;
        return old;
    }
    
    /**
     *  Return the console input pipe.
     *
     *  @return the console input pipe.
     **/
    protected final InputPipe getInputConsPipe() {
        return consin;
    }
    
    /**
     *  Set the console input pipe to the provided pipe. The previous pipe is
     *  returned.
     *
     *  @param ip the new input output pipe.
     *  @return the old input output pipe.
     **/
    protected final InputPipe setInputConsPipe(InputPipe ip) {
        InputPipe old = consin;
        
        consin = ip;
        
        consbuffer.clear();
        
        return old;
    }
    
    /**
     *  Return the console output pipe.
     *
     *  @return the console output pipe.
     **/
    protected final OutputPipe getOutputConsPipe() {
        return consout;
    }
    
    /**
     *  Set the console output pipe to the provided pipe. The previous pipe is
     *  returned.
     *
     *  @param op the new console output pipe.
     *  @return the old console output pipe.
     **/
    protected final OutputPipe setOutputConsPipe(OutputPipe op) {
        OutputPipe old = consout;
        consout = op;
        return old;
    }
    
    /**
     *  Return the name of the environment into which this ShellApp should
     *  return any environment variable result.
     *
     *  @return the name of the environment variable or null if no name has been
     *  set.
     **/
    protected final String getReturnVariable() {
        return returnVarName;
    }
    
    /**
     *  Set the name of the environment into which this ShellApp should
     *  return any environment variable result.
     *
     *  @param varName name of the environment variable.
     **/
    protected  final void setReturnVariable(String varName) {
        returnVarName = varName;
    }
    
    // IO Operations
    
    /**
     *  Print to standard output
     *
     *  @param line the line to print
     **/
    protected final void print(String line) {
        if( null == outputPipe ) {
            return;
        }
        
        pipePrint(outputPipe, line);
    }
    
    /**
     *  Print to standard output appending a newline.
     *
     *  @param line the line to print
     **/
    protected final void println(String line) {
        if( null == outputPipe ) {
            return;