/*
 *  eXist Open Source Native XML Database
 *  Copyright (C) 2001-07 The eXist Project
 *  http://exist-db.org
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public License
 *  as published by the Free Software Foundation; either version 2
 *  of the License, or (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 *  $Id: eXistURLStreamHandlerFactory.java 189 2007-03-30 15:02:18Z dizzzz $
 */

package org.exist.protocolhandler;

import java.net.URL;
import java.net.URLStreamHandler;
import java.net.URLStreamHandlerFactory;

import org.apache.log4j.Logger;
import org.exist.protocolhandler.protocols.xmldb.Handler;

/**
 * Factory class for creating custom stream handlers for the 'xmldb' protocol.
 *
 * @see java.net.URLStreamHandler
 * @see java.net.URLStreamHandlerFactory
 *
 * @author Dannes Wessels
 */
public class eXistURLStreamHandlerFactory implements URLStreamHandlerFactory {
    
    private final static Logger LOG = Logger.getLogger(eXistURLStreamHandlerFactory.class);
    
    public final static String JAVA_PROTOCOL_HANDLER_PKGS="java.protocol.handler.pkgs";
    public final static String EXIST_PROTOCOL_HANDLER="org.exist.protocolhandler.protocols";
    
    public static void init(){
        
        boolean initOK=false;
        try {
            URL.setURLStreamHandlerFactory(new eXistURLStreamHandlerFactory());
            initOK=true;
            LOG.info("Succesfully registered eXistURLStreamHandlerFactory.");
        } catch (Error ex){
            LOG.warn("The JVM has already an URLStreamHandlerFactory registered, skipping...");
        }
        
        if(!initOK){
            String currentSystemProperty = System.getProperty(JAVA_PROTOCOL_HANDLER_PKGS);
            
            if(currentSystemProperty==null){
                // Nothing setup yet
                LOG.info("Setting " + JAVA_PROTOCOL_HANDLER_PKGS + " to "
                    + EXIST_PROTOCOL_HANDLER);
                System.setProperty( JAVA_PROTOCOL_HANDLER_PKGS, EXIST_PROTOCOL_HANDLER );
                
            } else {
                // java.protocol.handler.pkgs is already setup, preserving settings
                if(currentSystemProperty.indexOf(EXIST_PROTOCOL_HANDLER)==-1){
                    // eXist handler is not setup yet
                    currentSystemProperty=currentSystemProperty+"|"+EXIST_PROTOCOL_HANDLER;
                    LOG.info("Setting " + JAVA_PROTOCOL_HANDLER_PKGS + " to " + currentSystemProperty);
                    System.setProperty( JAVA_PROTOCOL_HANDLER_PKGS, currentSystemProperty );
                } else {
                    LOG.info( "System property " + JAVA_PROTOCOL_HANDLER_PKGS + " has not been updated."); 
                }
            }
        }
    }
    
    /**
     *  Create Custom URL streamhandler for the <B>xmldb</B> protocol.
     *
     * @param protocol Protocol
     * @return Custom Xmldb stream handler.
     */
    public URLStreamHandler createURLStreamHandler(String protocol) {
        
        URLStreamHandler handler=null;
        
        if("xmldb".equals(protocol)){
            LOG.debug(protocol);
            handler=new Handler();
        } else {
            //LOG.error("Protocol should be xmldb, not "+protocol);
        }
        
        return handler;
    }
    
}