| gvSIG desktop 1

/* gvSIG. Geographic Information System of the Valencian Government

 *

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

 * of the Valencian Gobernment (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):

 * 2008 {DiSiD Technologies}  {Add pagination to a FeatureCollection}

 */

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

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

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

/**

 * Helper interface to access the values of a FeatureCollection by position.

 *

 * @author <a href="mailto:cordin@disid.com">C?sar Ordi?ana</a>

 */

public interface FeaturePagingHelper {

    static final int DEFAULT_PAGE_SIZE = 100;

    /**

     * Returns the current maximum number of Features per page.

     *

     * @return the current maximum page size

     */

    int getMaxPageSize();

    /**

     * Sets the current maximum number of Features per page. As the page size

     * changes, the current page of data is reloaded.

     * 

     * @param pageSize

     *            the maximum number of Feature per page

     * @throws DataException

     *             if there is an error reloading the current page

     */

    void setMaxPageSize(int pageSize) throws DataException;

    /**

     * Returns the number of pages available in the collection, calculated with

     * the total number of elements and the maximum number of elements per page.

     *

     * @return the number of pages available

     */

    long getNumPages();

    /**

     * Returns the number of the currently loaded page of Features (zero based).

     *

     * @return the current page number

     */

    long getCurrentPage();

    /**

     * Sets the current page number, and loads the Features for that page.

     * 

     * @param page

     *            the page to load

     * @throws DataException

     *             if there is an error setting the current page

     */

    void setCurrentPage(long page) throws DataException;

    /**

     * Returns the number of elements of the entire Collection.

     * 

     * @return the number of elements

     * @throws DataException

     *             if there is an error getting the total number of Features

     */

    long getTotalSize() throws DataException;

    /**

     * Returns the Feature located at the index position.

     * 

     * @param index

     *            to locate the Feature in the Collection

     * @return the Feature located at the index position

     * @throws DataException

     *             if there is an error getting the Feature

     */

    Feature getFeatureAt(long index) throws DataException;

    /**

     * Returns all the values of the current loaded page.

     *

     * @return all the values of the current loaded page

     */

    Feature[] getCurrentPageFeatures();

    /**

     * Returns the FeatureSet used to fetch the data.

     * 

     * @return the FeatureSet

     */

    FeatureSet getFeatureSet();

    /**

     * Returns the FeatureStore used to fetch the data.

     *

     * @return the FeatureStore

     */

    FeatureStore getFeatureStore();

    /**

     * Returns the query used to load the Features.

     * 

     * @return the query used to load the Features

     */

    FeatureQuery getFeatureQuery();

    /**

     * Reloads the current page of data from the collection.

     * 

     * @throws DataException

     *             if there is an error reloading the current page

     */

    void reloadCurrentPage() throws DataException;

        /**

         * Reloads everything, using the current query.

         * 

         * @throws DataException

         */

    void reload() throws DataException;

}