/*
 *    GeoTools - The Open Source Java GIS Toolkit
 *    http://geotools.org
 * 
 *    (C) 2002-2008, Open Source Geospatial Foundation (OSGeo)
 *
 *    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;
 *    version 2.1 of the License.
 *
 *    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.
 */
package org.geotools.util;


/**
 * A sub progress monitor, used to delegate a portion of work to a separate process.
 * <p>
 * Example:<pre><code>
 * if( progress == null ) progress = new NullProgressListener();
 * progress.started();
 * progress.setDecsription("Connect");
 * ..connect to data store and obtain feature collection...
 * progress.progress( 20 ); // connecting represents 20% of the work
 * progress.setDescription("Process features");
 * featureCollection.accepts( visitor, new SubProgress( progress, 80 ) );
 * progress.completed();
 * </code></pre>
 * 
 * @author Jody
 *
 *
 * @source $URL$
 */
public class SubProgressListener extends DelegateProgressListener {
    /** Initial starting value */
    float start;
    
    /** Amount of work we have been asked to perform */
    float amount;
    
    /** Scale between subprogress and delegate */
    float scale;
    
    /** running total of amount we have worked thus far */
    float progress;
   
    /**
     * Create a sub progress monitor, used to delegate work to a separate
     * process.
     * @param progress parent progress to notify as we get work done
     * @param amount amount of progress represented
     */
    public SubProgressListener( org.opengis.util.ProgressListener progress, float amount ) {
        super(progress);
        this.start = progress.getProgress();
        this.amount = (amount > 0.0f) ? amount : 0.0f;
        this.scale = this.amount / 100.0f;
    }
    public void started() {
        progress = 0.0f;
    }
    public void complete() {
        delegate.progress( start + amount );        
        progress = 100.0f;
    }
    public float getProgress() {
        return progress;
    }
    public void progress( float progress ) {
        this.progress = progress;
        super.progress(start + (scale * progress));
    }
}