IntermediateListener.java

/**
 * File: $HeadURL: https://hdt-java.googlecode.com/svn/trunk/hdt-java/src/org/rdfhdt/hdt/util/listener/IntermediateListener.java $
 * Revision: $Rev: 191 $
 * Last modified: $Date: 2013-03-03 11:41:43 +0000 (dom, 03 mar 2013) $
 * Last modified by: $Author: mario.arias $
 *
 * This library 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 2.1 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
 * 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
 *
 * Contacting the authors:
 *   Mario Arias:               mario.arias@deri.org
 *   Javier D. Fernandez:       jfergar@infor.uva.es
 *   Miguel A. Martinez-Prieto: migumar2@infor.uva.es
 *   Alejandro Andres:          fuzzy.alej@gmail.com
 */

package org.rdfhdt.hdt.util.listener;

import org.rdfhdt.hdt.listener.ProgressListener;

/**
 * Provides notifications by dividing an overall task in subtasks.
 * 
 * Call setRange() with the estimated percent of the overall task that
 * the subtask will take (i.e. 20-40%). Then call the substask providing
 * the IntermediateListener as Callback. The IntermediateListener will translate
 * the notifications of the subtask (in the 0-100 range) to the range supplied (20-40)
 * by using linear interpolation.
 * 
 * @author mario.arias
 *
 */
public class IntermediateListener implements ProgressListener {

	private ProgressListener child;
	private float min, max;
	
	/**
	 * Create an IntermediateListener that translates notifications of a
	 * child into a broader range.
	 * @param child
	 */
	public IntermediateListener(ProgressListener child) {
		this.child = child;
		this.min = 0;
		this.max = 100;
	}
	
	/**
	 * Forward a new notification adjusting the percent to the specified range.
	 */
	/* (non-Javadoc)
	 * @see hdt.ProgressListener#notifyProgress(float, java.lang.String)
	 */
	@Override
	public void notifyProgress(float level, String message) {
		if(child!=null) {
			float newlevel = min + level*(max-min)/100;
			child.notifyProgress(newlevel,message);
		}
	}
	
	/**
	 * Set the current range of notifications, For example if the range 20-40% is specified,
	 * when the child notifies 0, this IntermediateListener notifies the parent with 20%, and when
	 * the child notifies 100, the IntermediateListener notifies 40. Any intermediate values are
	 * linearly interpolated.
	 * @param min
	 * @param max
	 */
	public void setRange(float min, float max) {
		this.min = min;
		this.max = max;
	}

}