ShowSuccessorList.java

/***************************************************************************
 *                                                                         *
 *                           ShowSuccessorList.java                        *
 *                            -------------------                          *
 *   date                 : 09.09.2004, 18:12                              *
 *   copyright            : (C) 2004-2008 Distributed and                  *
 *                              Mobile Systems Group                       *
 *                              Lehrstuhl fuer Praktische Informatik       *
 *                              Universitaet Bamberg                       *
 *                              http://www.uni-bamberg.de/pi/              *
 *   email                : sven.kaffille@uni-bamberg.de                   *
 *                          karsten.loesing@uni-bamberg.de                 *
 *                                                                         *
 *                                                                         *
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   A copy of the license can be found in the license.txt file supplied   *
 *   with this software or at: http://www.gnu.org/copyleft/gpl.html        *
 *                                                                         *
 ***************************************************************************/

package de.uniba.wiai.lspi.chord.console.command;

import java.net.MalformedURLException;

import de.uniba.wiai.lspi.chord.com.local.ChordImplAccess;
import de.uniba.wiai.lspi.chord.com.local.Registry;
import de.uniba.wiai.lspi.chord.com.local.ThreadEndpoint;
import de.uniba.wiai.lspi.chord.data.URL;
import de.uniba.wiai.lspi.util.console.Command;
import de.uniba.wiai.lspi.util.console.ConsoleException;


/** 
 * <p>
 * {@link Command} to show the successors of a local chord node. 
 * </p>
 * To get a description of this command type <code>successors -help</code> 
 * into the {@link de.uniba.wiai.lspi.chord.console.Main console}.
 * @author  sven
 * @version 1.0.5
 */
public class ShowSuccessorList extends Command{
    
	/**
	 * Name of this {@link Command}.
	 */
    public static final String COMMAND_NAME = "successors";
    
    /**
     * The name of the parameter, that defines the node for which the 
     * successors should be shown. 
     */
    public static final String NODE_PARAM = "node";
    
    /** Creates a new instance of ShowSuccessorList 
     * @param toCommand1 
     * @param out1 */
    public ShowSuccessorList(Object[] toCommand1, java.io.PrintStream out1) {
        super(toCommand1, out1);
    }
    
    public void exec() throws de.uniba.wiai.lspi.util.console.ConsoleException {
        String nodeName = this.parameters.get(NODE_PARAM);
        if ( (nodeName == null) || (nodeName.length() == 0) ) {
            throw new ConsoleException("Not enough parameters. Please provide name of node "
                                      + "with help of " + NODE_PARAM + " parameter. ");
        }
        
        URL url = null; 
		try {
			url = new URL(URL.KNOWN_PROTOCOLS.get(URL.LOCAL_PROTOCOL) + "://" + nodeName + "/");
		} catch (MalformedURLException e1) {
			throw new ConsoleException(e1.getMessage());
		} 
        
        Registry reg = (Registry)this.toCommand[0];
        ThreadEndpoint ep = reg.lookup(url);
        if (ep != null) {
			this.out.println(ChordImplAccess.fetchChordImplOfNode(ep.getNode())
					.printSuccessorList());
		} else {
			this.out.println("Could not finde node with name " + nodeName);
		}
    }
    
    public String getCommandName() {
        return COMMAND_NAME;
    }
    
    public void printOutHelp() {
        this.out.println("This command displays the successor list of the node with the name,"
                   +" that is provided with help of parameter '" + NODE_PARAM + "'");
    }
    
}