/*
* 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.data.store;
import java.util.Iterator;
import org.opengis.feature.Feature;
/**
* Iterator wrapper which caps the number of returned features;
*
* @author Justin Deoliveira, The Open Planning Project
*
*
*
* @source $URL$
* http://svn.osgeo.org/geotools/trunk/modules/library/main/src/main/java/org/geotools/
* data/store/MaxFeaturesIterator.java $
*/
public class MaxFeaturesIterator<F extends Feature> implements Iterator<F> {
Iterator<F> delegate;
long start;
long end;
long counter;
public MaxFeaturesIterator(Iterator<F> delegate, long max) {
this(delegate, 0, max);
}
public MaxFeaturesIterator(Iterator<F> delegate, long start, long max) {
this.delegate = delegate;
this.start = start;
this.end = start + max;
counter = 0;
}
public Iterator<F> getDelegate() {
return delegate;
}
public void remove() {
delegate.remove();
}
public boolean hasNext() {
if (counter < start) {
// skip to just before start if needed
skip();
}
return delegate.hasNext() && counter < end;
}
public F next() {
if (counter < start) {
// skip to just before start if needed
skip();
}
if (counter <= end) {
counter++;
F next = delegate.next();
return next;
}
return null;
}
private void skip() {
if (counter < start) {
while (hasNext() && counter < start) {
counter++;
F skip = delegate.next(); // skip!
}
}
}
}