env.java

jxta-shell-src-2.4.zip 是最新版本的SHELL代码

/*
 * 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: env.java,v 1.11 2004/06/02 20:03:26 bondolo Exp $
 */

package net.jxta.impl.shell.bin.env;

import java.util.Enumeration;

import net.jxta.impl.shell.GetOpt;
import net.jxta.impl.shell.ShellApp;
import net.jxta.impl.shell.ShellEnv;
import net.jxta.impl.shell.ShellObject;

/**
 * Display environment variables
 */
public class env extends ShellApp {

    /**
     *  {@inheritDoc}
     **/
    public int startApp(String[] argv) {
        ShellEnv myEnv = getEnv();
        
        GetOpt options = new GetOpt( argv, 0, "" );
        
        while( true ) {
            int option;
            try {
                option = options.getNextOption();
            } catch( IllegalArgumentException badopt ) {
                consoleMessage( "Illegal argument :" + badopt );
                return syntaxError();
            }
            
            if( -1 == option ) {
                break;
            }
            
            switch( option ) {
                default :
                    consoleMessage( "Unrecognized option" );
                    return syntaxError();
            }
        }
        
        
        if ( null != options.getNextParameter() ) {
            consoleMessage( "Unsupported parameter" );
            return syntaxError();
        }
        
        Enumeration each = myEnv.elements();
        
        while (each.hasMoreElements()) {
            try {
                String objName = (String) each.nextElement();
                
                ShellObject obj = myEnv.get( objName );
                
                if (obj == null)
                    continue;
                
                println(objName + " = " + obj );
            } catch (Exception e) {
               printStackTrace( "Failure printing environment variable", e );
            }
        }
        
        return ShellApp.appNoError;
    }
    
    private int syntaxError() {
        consoleMessage("Usage: env ");
        return ShellApp.appParamError;
    }
    
    /**
     *  {@inheritDoc}
     **/
    public String getDescription() {
        return "Display environment variables";
    }
    
    /**
     *  {@inheritDoc}
     **/
    public void help() {
        println("NAME");
        println("     env  - " + getDescription() );
        println(" ");
        println("SYNOPSIS");
        println(" ");
        println("     env");
        println(" ");
        println("DESCRIPTION");
        println(" ");
        println("Displays all of the environment variables defined in the Shell.");
        println(" ");
        println("The following environment variables are defined by default:");
        println("    console     = Console for this Shell.");
        println("    consin      = Console InputPipe");
        println("    consout     = Console OutputPipe");
        println("    stdin       = Default InputPipe");
        println("    stdout      = Default OutputPipe");
        println("    shell       = This Shell object");
        println("    stdgroup    = current active PeerGroup");
        println("    rootgroup   = Default Infrastructure PeerGroup");
        println("    worldgroup  = World PeerGroup");
        println("    echo        = (if defined) Shell will echo all commands before execution");
        println("    parentShell = (if defined) Parent Shell of this Shell");
        println(" ");
        println("Shell environment variables are defined as a result of executing ");
        println("Shell commands or using the 'set' command. The '=' operator can " );
        println("be used to assign the result value of a command to a particular " );
        println("variable. For example `myenv = mkmsg` will assign a new message ");
        println("object to the 'myenv' environment variable." );
        println(" ");
        println("EXAMPLE");
        println(" ");
        println("    JXTA> env");
        println("    History = \"History\" [net.jxta.impl.shell.bin.history.HistoryQueue]" );
        println("    rootgroup = \"Default Group\" [net.jxta.impl.peergroup.RefCountPeerGroupInterface]" );
        println("    stdgroup = \"Default Group\" [net.jxta.impl.peergroup.RefCountPeerGroupInterface]" );
        println("    console = \"console\" [net.jxta.impl.shell.SwingShellConsole]" );
        println("    consout = \"Default Console OutputPipe\" [net.jxta.impl.shell.ShellOutputPipe]" );
        println("    worldgroup = \"World Peer Group\" [net.jxta.impl.peergroup.PeerGroupInterface]" );
        println("    stdout = \"Default OutputPipe\" [net.jxta.impl.shell.ShellOutputPipe]" );
        println("    stdin = \"Default InputPipe\" [net.jxta.impl.shell.ShellInputPipe]" );
        println("    shell = \"Shell\" [net.jxta.impl.shell.bin.Shell.Shell]" );
        println("    consin = \"Default Console InputPipe\" [net.jxta.impl.shell.ShellInputPipe]" );
        println("    JXTA> " );
        println(" ");
        println("This command will display all defined environment variables.");
        println(" ");
        println("SEE ALSO");
        println("    set unset Shell");
    }
}