history.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: history.java,v 1.1 2001/06/17 14:28:51 wiarda Exp $
 */

package net.jxta.impl.shell.bin.history;
import net.jxta.impl.shell.*;


public class history extends ShellApp {
    /** The class that manages the history queues
    private static HistoryQueue queues = new HistoryQueue();
    
    /** Used to generate unique names for registered shells */
    private static int unique = 0; 

    public history() {        
    }
    
    public void stopApp () {
    }
    
    public int startApp (String[] args) {
        ShellEnv env = getEnv();
        ShellObject obj = env.get ("History");
        HistoryQueue queue;
        
        if(obj != null && HistoryQueue.class.isInstance( obj.getObject() )){
	    queue = (HistoryQueue)obj.getObject();
            println(queue.printHistory());
	}
       
        return ShellApp.appNoError;
    }
    
    
  
   public void help() {
        println("NAME");
        println("     history  - prints out a list of previous commands");
        println(" ");
        println("SYNOPSIS");
        println(" ");
        println("     history");
        println(" ");
        println("DESCRIPTION");
        println(" ");
        println(" Lists the commands previously typed.");
        println(" Commands can be recalled in two ways:");
        println(" Use the up and down arrow keys to navigate");
        println(" through the list of commands.");
        println(" Use !<number>, where number is the number of");
        println(" the command as shown in the list displayed");
        println(" by history.");
        println(" ");
        println("SEE ALSO");
    }
}