| gvSIG desktop 1

/* gvSIG. Sistema de Informaci?n Geogr?fica de la Generalitat Valenciana

 *

 * Copyright (C) 2004 IVER T.I. and Generalitat Valenciana.

 *

 * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307,USA.

 *

 * For more information, contact:

 *

 *  Generalitat Valenciana

 *   Conselleria d'Infraestructures i Transport

 *   Av. Blasco Ib??ez, 50

 *   46010 VALENCIA

 *   SPAIN

 *

 *      +34 963862235

 *   gvsig@gva.es

 *      www.gvsig.gva.es

 *

 *    or

 *

 *   IVER T.I. S.A

 *   Salamanca 50

 *   46005 Valencia

 *   Spain

 *

 *   +34 963163400

 *   dac@iver.es

 */

package org.gvsig.fmap.mapcontext;

import java.awt.geom.Rectangle2D;

import org.gvsig.tools.ToolsLocator;

import org.gvsig.tools.dynobject.DynStruct;

import org.gvsig.tools.persistence.PersistenceManager;

import org.gvsig.tools.persistence.Persistent;

import org.gvsig.tools.persistence.PersistentState;

import org.gvsig.tools.persistence.exception.PersistenceException;

/**

 * <p><code>ExtentHistory</code> is designed for managing a history of extents.</p>

 *

 * <p>Note: An <i>extent</i> is a re.setMandatory(true)ctangular area, with information of its top-left 2D corner.</p>

 *

 * @author Vicente Caballero Navarro

 */

public class ExtentHistory implements Persistent {

        /**

         * <p>Maximum number of extents that can store.</p>

         */

        private int NUMREC;

        /**

         * <p>Array with the extents.</p>

         *

         * @see #hasPrevious()

         * @see #put(Rectangle2D)

         * @see #get()

         * @see #removePrev()

         */

        private Rectangle2D[] extents;

        /**

         * <p>Number of extents stored.</p>

         *

         * @see #hasPrevious()

         * @see #put(Rectangle2D)

         * @see #get()

         * @see #removePrev()

         */

        private int num = 0;

        /**

         * <p>Creates a new instance of <code>ExtentsHistory</code> with an history of 10 extents.</p>

         */

        public ExtentHistory() {

                this(10);

        }

        /**

         * <p>Creates a new instance of <code>ExtentsHistory</code> with an history of <code>numEntries</code> extents.</p>

         *

         * @param numEntries the maximum number of extents that will store the instance

         */

        public ExtentHistory(int numEntries) {

                NUMREC = numEntries;

                extents = new Rectangle2D[NUMREC];

        }

        /**

         * <p>Appends the specified extent to the end of this history.</p>

         *

         * @param ext the new extent

         *

         * @see #get()

         * @see #hasPrevious()

         */

        public void put(Rectangle2D ext) {

                if ((ext != null) && ((num < 1) || (ext != extents[num - 1]))) {

                        if (num < (NUMREC)) {

                                extents[num] = ext;

                                num = num + 1;

                        } else {

                                for (int i = 0; i < (NUMREC - 1); i++) {

                                        extents[i] = extents[i + 1];

                                }

                                extents[num - 1] = ext;

                        }

                }

        }

        /**

         * <p>Returns <code>true</code> if there are extents registered.</p>

         *

         * @return <code>true</code> if there are extents registered; <code>false</code> otherwise

         *

         * @see #put(Rectangle2D)

         * @see #removePrev()

         * @see #get()

         */

        public boolean hasPrevious() {

                return num > 0;

        }

        /**

         * <p>Returns the last extent in the history.</p>

         *

         * @return the last extent in the history

         *

         * @see #put(Rectangle2D)

         * @see #getXMLEntity()

         */

        public Rectangle2D get() {

                if (num <= 0) {

                        return null;

                }

                Rectangle2D ext = extents[num - 1];

                return ext;

        }

        /**

         * <p>Extracts (removing) the last extent from the history.</p>

         *

         * @return last extent in the history

         *

         * @see #hasPrevious()

         */

        public Rectangle2D removePrev() {

                if (num <= 0) {

                        return null;

                }

                Rectangle2D ext = extents[--num];

                return ext;

        }

        public void loadFromState(PersistentState state)

                        throws PersistenceException {

                num = state.getInt("num");

                NUMREC = state.getInt("numrec");

                extents = (Rectangle2D[]) state.getArray("extents", Rectangle2D.class);

        }

        /**

         * <p>

         * Returns information of this object. All information is stored as

         * properties:<br>

         * </p>

         * <p>

         * <b>Properties:</b>

         * <ul>

         * <li><i>className</i>: name of this class.

         * <li><i>num</i>: number of extents registered.

         * <li><i>numrec</i>: maximum number of extents that can register.

         * <li><i>extents</i>: .

         * </ul>

         * </p>

         *

         */

        public void saveToState(PersistentState state) throws PersistenceException {

                state.set("num", num);

                state.set("numrec", NUMREC);

                state.set("extents", extents);

        }

        public static void registerPersistent() {

                PersistenceManager manager = ToolsLocator.getPersistenceManager();

                DynStruct definition = manager.addDefinition(

                                ExtentHistory.class,

                                "ExtentHistory",

                                "ExtentHistory Persistence definition",

                                null,

                                null

                );

                definition.addDynFieldInt("num").setMandatory(true);

                definition.addDynFieldInt("numrec").setMandatory(true);

                definition.addDynFieldArray("extents").setClassOfItems(Rectangle2D.class).setMandatory(true);

        }

}