decodertemplate.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/DecoderTemplate.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.EncObjectSignature;
import jacomma.icm.io.EncObjectDecoder;

import jacomma.util.Cache;

import java.util.Iterator;
import java.util.Set;

/**
 * TBA
 **/
public abstract class DecoderTemplate implements EncObjectDecoder {

	protected Set all_ = new java.util.HashSet( 4 );
	protected Set some_ = new java.util.HashSet( 4 );
	protected Cache cache_ = new Cache();

	protected DecoderTemplate(){}

	public Object decode( EncObject obj ) {
		return decode( obj, null );
	}

	public boolean canHandle( EncObject obj, Object hint ) {
		return canHandle( obj );
	}

	public boolean canHandle( EncObject obj ) {
		return canHandle( obj.getType() );
	}

	public boolean canHandleSome( EncObjectType t ) {
		return check( t, some_ );
	}

	public boolean canHandle( EncObjectType t ) {
		return check( t, all_ );
	}

	
	protected boolean check( EncObjectType t, Set set ) {
		return set.contains( t );
	}


	// utility class for creating cache keys for Objects to be decoded
	protected class CacheKey {
		Object obj_;
		Object hint_;
		
		public CacheKey( Object obj, Object hint ) {
			obj_ = obj;
			hint_ = hint;
		}
		
		public CacheKey( Object obj ) {
			obj_ = obj;
		}
		
		public int hashCode() {
			return obj_.hashCode();
		}
		
		public boolean equals( Object obj ) {
			try {
				return obj_.equals( ((CacheKey)obj).obj_ )
					&& ( (hint_ == null) ? 
						 (((CacheKey)obj).hint_ == null) : 
						 hint_.equals( ((CacheKey)obj).hint_ ) );
			} catch ( ClassCastException exc ) {
				return false;
			}
		}

	}
}