Application: gvSIG desktop

/**

 * gvSIG. Desktop Geographic Information System.

 *

 * Copyright (C) 2007-2013 gvSIG Association.

 *

 * 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 3

 * 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.

 *

 * For any additional information, do not hesitate to contact us

 * at info AT gvsig.com, or visit our website www.gvsig.com.

 */

package org.gvsig.fmap.dal.spi;

import org.gvsig.fmap.dal.feature.spi.FeatureProvider;

import org.gvsig.fmap.dal.resource.Resource;

import org.gvsig.fmap.dal.resource.ResourceAction;

import org.gvsig.tools.dispose.DisposableIterator;

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

/**

 * Abstract base implementation for data iterators.

 * 

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

 */

public abstract class AbstractDataProviderIterator extends AbstractDisposable

                implements DisposableIterator {

        private final DataStoreProvider dataStoreProvider;

        private final ResourceAction nextResourceAction = new ResourceAction() {

                public Object run() throws Exception {

                        dataStoreProvider.open();

                        return internalNext();

                }

        };

        private final ResourceAction hasNextResourceAction = new ResourceAction() {

                public Object run() throws Exception {

                        boolean value = internalHasNext();

                        return value ? Boolean.TRUE : Boolean.FALSE;

                }

        };

        /**

         * Creates a new iterator instance.

         * 

         * @param storeProvider

         *            to load the {@link FeatureProvider}s from

         */

        public AbstractDataProviderIterator(DataStoreProvider dataStoreProvider) {

                this.dataStoreProvider = dataStoreProvider;

        }

    public Object next() {

                return getResource().execute(nextResourceAction);

        }

    public boolean hasNext() {

                Object hasNext = getResource().execute(hasNextResourceAction);

                return ((Boolean) hasNext).booleanValue();

        }

        /**

         * Returns the {@link Resource} from where the data is going to be loaded.

         * 

         * @return the {@link Resource} from where the data is going to be loaded

         */

        protected final Resource getResource() {

                return getDataStoreProvider().getResource();

        }

        /**

         * Returns the {@link DataStoreProvider} to load the Iterator data.

         * 

         * @return the {@link DataStoreProvider}

         */

        protected DataStoreProvider getDataStoreProvider() {

                return dataStoreProvider;

        }

        /**

         * Returns the next iterator element. It is the child classes implementation

         * for the {@link #next()} method.

         * 

         * @return the next element

         */

        protected abstract Object internalNext();

        /**

         * Returns if there are more elements to get from the iterator. It is the

         * child classes implementation for the {@link #hasNext()} method.

         * 

         * @return if there are more elements

         */

        protected abstract boolean internalHasNext();

}