readertemplate.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/ReaderTemplate.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.EncObjectReader;


public abstract class ReaderTemplate  implements EncObjectReader {

	protected java.io.InputStream stream_;
	protected boolean done_;
	
	private EncObject obj_;

	protected ReaderTemplate(){}

	protected int readNextByte() throws java.io.IOException {
		int r;
		if ( (r = stream_.read()) != -1 )
			return r;
		else
			throw new java.io.IOException( "End of Stream." );
	}
	
	public EncObject getObject() {
		return (obj_ == null) ? (obj_ = makeObject()) : obj_;
	}
	
	protected abstract EncObject makeObject();

	public void start( java.io.InputStream stream ) 
		throws java.io.IOException {
		
		done_ = false;
		stream_ = stream;
		obj_ = null;

	}
	

	public boolean hasNext() {
		return !done_;
	}


	public boolean canHandle( Object obj ) {
		if ( obj instanceof EncObjectType )
			return ((EncObjectReader)this).canHandle( (EncObjectType)obj );
		else
			return false;
	}

	public Object clone() {
		try {
			return super.clone();
		} catch ( CloneNotSupportedException exc ) {
			throw new jacomma.util.CheckedException( exc );
		}
	}

}