Application: gvSIG desktop

/* gvSIG. Geographic Information System of the Valencian Government

 *

 * Copyright (C) 2007-2008 Infrastructures and Transports Department

 * of the Valencian Government (CIT)

 * 

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 2

 * of the License, or (at your option) any later version.

 * 

 * This program 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 General Public License for more details.

 * 

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, 

 * MA  02110-1301, USA.

 * 

 */

/*

 * AUTHORS (In addition to CIT):

 * 2009 {}  {{Task}}

 */

package org.gvsig.fmap.dal.feature.spi;

import java.util.Iterator;

import org.gvsig.fmap.dal.exception.DataException;

import org.gvsig.fmap.dal.feature.FeatureQuery;

import org.gvsig.fmap.dal.feature.FeatureType;

import org.gvsig.tools.dispose.DisposableIterator;

import org.gvsig.tools.dispose.impl.AbstractDisposable;

/**

 * Base implementation for {@link FeatureSetProvider}s, adding some utility

 * methods.

 * 

 * @author 2009- <a href="cordinyana@gvsig.org">C?sar Ordi?ana</a> - gvSIG team

 */

public abstract class AbstractFeatureSetProvider extends AbstractDisposable

                implements FeatureSetProvider {

        private final AbstractFeatureStoreProvider store;

        private final FeatureQuery query;

        private final FeatureType featureType;

        /**

         * Creates a new {@link FeatureSetProvider}.

         * 

         * @param store

         *            the underlying {@link FeatureStoreProvider} to get the data

         *            from

         * @param query

         *            used to create the {@link FeatureSetProvider}

         * @param featureType

         *            the type of feature to get

         */

        public AbstractFeatureSetProvider(AbstractFeatureStoreProvider store,

                        FeatureQuery query, FeatureType featureType) {

                this.store = store;

                this.query = query;

                this.featureType = featureType;

        }

        /**

         * Return the {@link AbstractFeatureStoreProvider}.

         * 

         * @return the store

         */

        protected AbstractFeatureStoreProvider getStore() {

                return store;

        }

        /**

         * Returns the {@link FeatureQuery} used to create this set.

         * 

         * @return the query

         */

        protected FeatureQuery getQuery() {

                return query;

        }

        /**

         * Returns the type of features to load.

         * 

         * @return the featureType

         */

        protected FeatureType getFeatureType() {

                return featureType;

        }

        public final DisposableIterator fastIterator() throws DataException {

                return fastIterator(0);

        }

        public final DisposableIterator fastIterator(long index)

                        throws DataException {

                return createFastIterator(index);

        }

        public final DisposableIterator iterator() throws DataException {

                return iterator(0);

        }

        public final DisposableIterator iterator(long index) throws DataException {

                return createIterator(index);

        }

        /**

         * Creates a new {@link Iterator}, begginning at the specified data index.

         * 

         * @param index

         *            the first element position to be returned by the

         *            {@link Iterator}

         * @return a new {@link Iterator}

         * @throws DataException

         *             if there is an error creating the {@link Iterator}

         */

        protected abstract AbstractFeatureProviderIterator createIterator(long index)

                        throws DataException;

        /**

         * Creates a new fast {@link Iterator}, begginning at the specified data

         * index. By fast this means the object instances of data (

         * {@link FeatureProvider}) may be reused between the

         * {@link Iterator#next()} method invocations.

         * 

         * @param index

         *            the first element position to be returned by the

         *            {@link Iterator}

         * @return a new {@link Iterator}

         * @throws DataException

         *             if there is an error creating the {@link Iterator}

         */

        protected abstract AbstractFeatureProviderIterator createFastIterator(

                        long index) throws DataException;

}