mapdecoder.java

Java Communicating Agents是一个用于开发网络反应式信息agent的框架

/*
 * $Source: /home/data/cvsroot/src/jacomma/icm/io/imp/MapDecoder.java,v $
 * $Revision: 1.4 $
 * $Date: 2000/10/28 20:09:07 $
 *
 * This file is part of the jacomma framework
 * Copyright (c) 2000 	Dimitrios Vyzovitis
 *			mailto:[e-mail]
 *			
 *
 *			
 *			
 *			
 *
 *	This library is free software; you can redistribute it and/or modify
 *	it under the terms of the GNU Library General Public License as published by
 *	the Free Software Foundation; either version 2 of the License, or
 *	(at your option) any later version.
 *
 *	This library 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 Library General Public License for more details.
 *
 *	You should have received a copy of the GNU Library General Public License
 *	along with this library; if not, write to the Free Software
 *	Foundation, Inc., 59 Temple Place, Suite 330, 
 *	Boston, MA  02111-1307  USA
 */

package jacomma.icm.io.imp;

import jacomma.icm.io.EncObject;
import jacomma.icm.io.EncObjectType;
import jacomma.icm.io.EncObjectDecoder;
import jacomma.icm.io.EncObjectSignature;

import java.util.Map;
import java.util.HashMap;
import java.util.List;

/**
 * TBA
 **/
public class MapDecoder extends DecoderTemplate {

	String msig_ = EncObjectSignature.List + EncObjectSignature.Tuple + "\002";

	public MapDecoder() {
		some_.add( EncObjectType.List );
	}
	
	public boolean canHandle( EncObject obj ) {
		return EncObjectSignature.signatureOf( obj ).startsWith( msig_ );
	}
	
	public boolean canHandle( EncObject obj, Object hint ) {
		return canHandle( obj );
	}

	public Object decode( EncObject obj, Object hint ) {
		// hint can be a Map instance to fill with the elements
		CacheKey key = new CacheKey( obj, hint );
		Object dobj = cache_.get( key );
		
		if ( dobj == null ) {
			Map m = (hint instanceof Map) ? (Map)hint : new java.util.HashMap();
			EncObject[] elements = (EncObject[])obj.getValue();
			EncObjectDecoder dec = (elements.length > 0) ? Registry.instance.getDecoder( elements[0] ) : null;
			for ( int i = 0; i < elements.length; i++ ) {
				List elem = (List)dec.decode( elements[i] );
				m.put( elem.get( 0 ), elem.get( 1 ) );
			}
			
			dobj = cache_.try_put( key, m );
		}
		
		return dobj;
	}

}