version.java

有关java 的p2p应用,是一般很好的教程,有兴趣的朋友应该好好阅读一下

/*
 * 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: version.java,v 1.1013 2004/06/23 19:02:38 bondolo Exp $
 */


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

import net.jxta.impl.shell.*;
import net.jxta.impl.shell.bin.Shell.*;
import java.util.*;

/**
 * version command
 */

public class version extends ShellApp {
    private static String  version = "2.3-pre-16 157c 06-15-2004";
    
    /**
     *  {@inheritDoc}
     **/
    public int startApp(String[] argv) {
        boolean verbose = false;
        
        GetOpt options = new GetOpt( argv, 0, "v" );
        
        while( true ) {
            int option;
            try {
                option = options.getNextOption();
            } catch( IllegalArgumentException badopt ) {
                consoleMessage( "Illegal argument :" + badopt );
                return syntaxError();
            }
            
            if( -1 == option ) {
                break;
            }
            
            switch( option ) {
                
                case 'v' : 
                    verbose = true;
                    break;
                    
                default :
                    consoleMessage( "Unrecognized option" );
                    return syntaxError();
            }
        }
        
        if ( null != options.getNextParameter() ) {
            consoleMessage( "Unsupported parameter" );
            return syntaxError();
        }
        
        
        Package shellPackage = Package.getPackage( "net.jxta.impl.shell" );
        
        if( (null == shellPackage) || (null == shellPackage.getImplementationVersion()) ) {
            consoleMessage( "Version information not available" );
            return ShellApp.appMiscError;
        }
        
        if( !verbose ) {
            println( shellPackage.getImplementationVersion() );
        } else {
            println( "Specification Title : " + shellPackage.getSpecificationTitle() );
            println( "Specification Vendor : " + shellPackage.getSpecificationVendor() );
            println( "Specification Version : " + shellPackage.getSpecificationVersion() );
            
            println( " " );

            println( "Implementation Title : " + shellPackage.getImplementationTitle() );
            println( "Implementation Vendor : " + shellPackage.getImplementationVendor() );
            println( "Implementation Version : " + shellPackage.getImplementationVersion() );
        }
        
        return ShellApp.appNoError;
    }
      
    private int syntaxError() {
        consoleMessage("Usage: version [-v]");
        return ShellApp.appParamError;
    }
    
    /**
     *  {@inheritDoc}
     **/
    public String getDescription() {
        return "Display the version number of this Shell instance.";
    }
    
    /**
     *  {@inheritDoc}
     **/
    public void help() {
        println("NAME");
        println("     version - " + getDescription() );
        println(" ");
        println("SYNOPSIS");
        println(" ");
        println("     version [-v]");
        println(" ");
        println("OPTIONS");
        println(" ");
        println("     [-v]  Print verbose information.");
        println(" ");
        println("DESCRIPTION");
        println(" ");
        println("The version command displays the version number associated ");
        println("with this Shell instance. In order to work correctly the");
        println("shell must be packaged in a jar file with a complete manifest");
        println("(this is normally the case)." );
        println(" ");
    }
}