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.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;

import org.gvsig.tools.util.Callable;

/**

 * <p>

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

 * </p>

 * <p>

 * Note: An <i>extent</i> is a rectangular 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;

  private Rectangle2D[] extentsNext;

  /**

   * <p>

   * Number of extents stored.

   * </p>

   *

   * @see #hasPrevious()

   * @see #put(Rectangle2D)

   * @see #get()

   * @see #removePrev()

   */

  private int num = 0;

  private int numNext = 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];

    extentsNext = 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;

  }

  public boolean hasNext() {

    return numNext > 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;

  }

  public Rectangle2D getNext() {

    if (numNext <= 0) {

      return null;

    }

    Rectangle2D ext = extentsNext[numNext - 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;

    }

    if (numNext < (NUMREC)) {

      extentsNext[numNext] = extents[num - 1];

      numNext++;

    }

    else {

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

        extentsNext[i] = extentsNext[i + 1];

      }

      extentsNext[numNext - 1] = extents[num - 1];

    }

    Rectangle2D ext = extents[--num];

    return ext;

  }

  /**

   * <p>

   * Extracts (removing) the last extent from the history.

   * </p>

   *

   * @return last extent in the history

   * @see #hasNext()

   */

  public Rectangle2D removeNext() {

    if (numNext <= 0) {

      return null;

    }

    if (num < (NUMREC)) {

      extents[num] = extentsNext[numNext - 1];

    }

    else {

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

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

      }

      extents[num - 1] = extentsNext[numNext - 1];

    }

    Rectangle2D ext = extentsNext[--numNext];

    return ext;

  }

  public void clear() {

    num = 0;

    numNext = 0;

  }

  public void loadFromState(PersistentState state) throws PersistenceException {

    num = state.getInt("num");

    NUMREC = state.getInt("numrec");

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

    extentsNext = (Rectangle2D[]) state.getArray("extentsNext",

        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);

    state.set("extentsNext", extentsNext);

  }

  public static class RegisterPersistence implements Callable {

    public Object call() {

      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);

      definition.addDynFieldArray("extentsNext")

          .setClassOfItems(Rectangle2D.class).setMandatory(true);

      return Boolean.TRUE;

    }

  }

}