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The main module contains the GeoTools public interfaces that are used by other GeoTools modules (and GeoTools applications). Where possible we make use industry standard terms as provided by OGC and ISO standards. The formal GeoTools public api consists of gt-metadata, jts and the gt-main module. The main module contains the default implementations that are available provided to other GeoTools modules using our factory system. Factories are obtained from an appropriate FactoryFinder, giving applications a chance configure the factory used using the Factory Hints facilities. FilterFactory ff = CommonFactoryFinder.getFilterFactory(); Expression expr = ff.add( expression1, expression2 ); If you find yourself using implementation specific classes chances are you doing it wrong: Expression expr = new AddImpl( expression1, expressiom2 );

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/*
 *    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.feature.collection;

import org.geotools.data.simple.SimpleFeatureIterator;
import org.opengis.feature.simple.SimpleFeature;

/**
 * SimpleFeatureIterator wrapper which can use a start and end bounds to cap the number of returned
 * features.
 *
 * @author Justin Deoliveira, The Open Planning Project
 */
public class MaxFeaturesSimpleFeatureIterator implements SimpleFeatureIterator {

    SimpleFeatureIterator delegate;

    long start;
    long end;
    long counter;

    public MaxFeaturesSimpleFeatureIterator(SimpleFeatureIterator iterator, long max) {
        this(iterator, 0, max);
    }

    public MaxFeaturesSimpleFeatureIterator(SimpleFeatureIterator delegate, long start, long max) {
        this.delegate = delegate;
        this.start = start;
        this.end = start + max;
        counter = 0;
    }

    public SimpleFeatureIterator getDelegate() {
        return delegate;
    }

    public boolean hasNext() {
        if (counter < start) {
            // skip to just before start if needed
            skip();
        }
        return delegate.hasNext() && counter < end;
    }

    public SimpleFeature next() {
        if (counter < start) {
            // skip to just before start if needed
            skip();
        }
        if (counter <= end) {
            counter++;
            SimpleFeature next = delegate.next();
            return next;
        }
        return null;
    }

    private void skip() {
        if (counter < start) {
            while (delegate.hasNext() && counter < start) {
                counter++;
                @SuppressWarnings("unused")
                SimpleFeature skip = delegate.next(); // skip!
            }
        }
    }

    @Override
    public void close() {
        delegate.close();
    }
}