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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) 2003-2008, 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;

import java.io.IOException;
import java.util.NoSuchElementException;
import org.opengis.feature.Feature;
import org.opengis.feature.IllegalAttributeException;
import org.opengis.feature.type.FeatureType;

/**
 * Basic support for a FeatureReader that limits itself to the
 * number of features passed in.
 *
 * @author Chris Holmes
 * @version $Id$
 */
public class MaxFeatureReader
        implements DelegatingFeatureReader {

    protected final FeatureReader featureReader;
    protected final int maxFeatures;
    protected int counter = 0;

    /**
     * Creates a new instance of MaxFeatureReader
     *
     * @param featureReader FeatureReader being maxed
     */
    public MaxFeatureReader(FeatureReader featureReader, int maxFeatures) {
        this.featureReader = featureReader;
        this.maxFeatures = maxFeatures;
    }

    public FeatureReader getDelegate() {
        return featureReader;
    }

    public F next() throws IOException, IllegalAttributeException, NoSuchElementException {
        if (hasNext()) {
            counter++;

            return featureReader.next();
        } else {
            throw new NoSuchElementException("No such Feature exists");
        }
    }

    public void close() throws IOException {
        featureReader.close();
    }

    public T getFeatureType() {
        return featureReader.getFeatureType();
    }

    /**
     * @return true if the featureReader has not passed the max and still has more
     *     features.
     * @throws IOException If the reader we are filtering encounters a problem
     */
    public boolean hasNext() throws IOException {
        return (featureReader.hasNext() && (counter < maxFeatures));
    }
}