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 {

  private static final String FIELD_CURRENT_EXTENT = "current";

  private static final String FIELD_NUM_PREVIOUS = "num";

  private static final String FIELD_NUM_NEXT = "numnext";

  private static final String FIELD_NUM_RECORDS = "numrec";

  private static final String FIELD_PREVIOUS_EXTENTS = "extents";

  private static final String FIELD_NEXT_EXTENTS = "extentsNext";

  /**

   * <p>

   * Maximum number of extents that can store.

   * </p>

   */

  private int NUMREC;

  /**

   * <p>

   * Array with the previous extents.

   * </p>

   *

   * @see #hasPrevious()

   * @see #put(Rectangle2D)

   * @see #getPrev()

   * @see #popPrev()

   */

  private Rectangle2D[] extentsPrev;

  /**

   * <p>

   * Array with the next extents.

   * </p>

   *

   * @see #hasNext()

   * @see #putNext(Rectangle2D)

   * @see #getNext()

   * @see #popNext()

   */

  private Rectangle2D[] extentsNext;

  /**

   * <p>

   * The current extent of the viewport.

   * </p>

   */

  private Rectangle2D currentExtent;

  /**

   * <p>

   * Number of previous extents stored.

   * </p>

   *

   * @see #hasPrevious()

   * @see #put(Rectangle2D)

   * @see #getPrev()

   * @see #popPrev()

   */

  private int numPrev = 0;

  /**

   * <p>

   * Number of next extents stored.

   * </p>

   *

   * @see #hasNext()

   * @see #putNext(Rectangle2D)

   * @see #getNext()

   * @see #popNext()

   */

  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;

    extentsPrev = new Rectangle2D[NUMREC];

    extentsNext = new Rectangle2D[NUMREC];

  }

  /**

   * <p>

   * Appends the specified extent at the end of the array of previous zooms.

   * </p>

   *

   * @param ext the new extent

   */

  public void put(Rectangle2D ext) {

    // Si al cargar de la persistencia currentExtent es null ViewPort nos dar? su extent

    if(currentExtent == null) {

      this.currentExtent = ext;

      return;

    }

    if ( !ext.equals(getPrev()) && !ext.equals(getNext()) ) {

      clearNumNext();

    }

    pushPrevious(currentExtent);

    this.currentExtent = ext;

  }

  /**

   * <p>

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

   * </p>

   *

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

   *         <code>false</code> otherwise

   */

  public boolean hasPrevious() {

    return numPrev > 0;

  }

  /**

   * <p>

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

   * </p>

   *

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

   *         <code>false</code> otherwise

   */

  public boolean hasNext() {

    return numNext > 0;

  }

  /**

   * <p>

   * Returns the last previous extent from the history.

   * </p>

   *

   * @return the last previous extent from the history

   */

  public Rectangle2D getPrev() {

    if (numPrev <= 0) {

      return null;

    }

    Rectangle2D ext = extentsPrev[numPrev - 1];

    return ext;

  }

  /**

   * <p>

   * Returns the last next extent from the history.

   * </p>

   *

   * @return the last next extent from the history

   */

  public Rectangle2D getNext() {

    if (numNext <= 0) {

      return null;

    }

    Rectangle2D ext = extentsNext[numNext - 1];

    return ext;

  }

  /**

   * <p>

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

   * </p>

   *

   * @return last previous extent from the history

   */

  private Rectangle2D popPrev() {

    if (numPrev <= 0) {

      return null;

    }

    Rectangle2D ext = extentsPrev[--numPrev];

    return ext;

  }

  /**

   * <p>

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

   * </p>

   *

   * @return last next extent from the history

   */

  private Rectangle2D popNext() {

    if (numNext <= 0) {

      return null;

    }

    Rectangle2D ext = extentsNext[--numNext];

    return ext;

  }

  /**

   * <p>

   * Sets to zero the number of previous extents from the history.

   * </p>

   */

  private void clearNumPrev() {

    numPrev = 0;

  }

  /**

   * <p>

   * Sets to zero the number of next extents from the history.

   * </p>

   */

  private void clearNumNext() {

    numNext = 0;

  }

  /**

   * <p>

   * Adds the current extent to the next extent history and sets the last

   * previous extent as the new current extent.

   * </p>

   *

   * @return the last previous extent as the new current extent

   */

  public Rectangle2D setPreviousExtent() {

    if (currentExtent != null) {

      pushNext(currentExtent);

    }

    currentExtent = popPrev();

    return currentExtent;

  }

  /**

   * <p>

   * Adds the specified extent to the next extent history.

   * If the array of next extents is complete, loses the

   * first extent of the array and adds the new one at the end.

   * </p>

   *  

   */

  private void pushNext(Rectangle2D ext) {

    if (numNext < (NUMREC)) {

      extentsNext[numNext] = ext;

      numNext = numNext + 1;

    }

    else {

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

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

      }

      extentsNext[numNext - 1] = ext;

    }

  }

  /**

   * <p>

   * Adds the current extent to the previous extent history and sets the last

   * next extent as the new current extent.

   * </p>

   * 

   * @return the last next extent as the new current extent

   */

  public Rectangle2D setNextExtent() {

    if (currentExtent != null) {

      pushPrevious(currentExtent);

    }

    currentExtent = popNext();

    return currentExtent;

  }

  /**

   * <p>

   * Adds the specified extent to the previous extent history.

   * If the array of previous extents is complete, loses the

   * first extent of the array and adds the new one at the end.

   * </p>

   *  

   */

  private void pushPrevious(Rectangle2D ext) {

    if (numPrev < (NUMREC)) {

      extentsPrev[numPrev] = ext;

      numPrev++;

    } else {

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

        extentsPrev[i] = extentsPrev[i + 1];

      }

      extentsPrev[numPrev - 1] = ext;

    }

  }

  /**

   * <p>

   * Returns the current extent.

   * </p>

   *  

   * @return the current extent

   */

  public Rectangle2D getCurrent() {

    return currentExtent;

  }

  public void loadFromState(PersistentState state) throws PersistenceException {

    if (state.hasValue("num")) {

      numPrev = state.getInt("num");

    }

    else {

      clearNumPrev();

    }

    if (state.hasValue("numnext")) {

      numNext = state.getInt("numnext");

    }

    else {

      clearNumNext();

    }

    if (state.hasValue("numrec")) {

      NUMREC = state.getInt("numrec");

    }

    else {

      NUMREC = 10;

    }

    if (state.hasValue("extents")) {

      extentsPrev = (Rectangle2D[]) state

          .getArray("extents", Rectangle2D.class);

    }

    else {

      extentsPrev = new Rectangle2D[NUMREC];

      clearNumPrev();

    }

    if (state.hasValue("extentsNext")) {

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

          Rectangle2D.class);

    }

    else {

      extentsNext = new Rectangle2D[NUMREC];

      clearNumNext();

    }

    if (state.hasValue("current")) {

      currentExtent = (Rectangle2D) state.get("current");

    }

    else {

      currentExtent = null;

    }

  }

  /**

   * <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(FIELD_NUM_PREVIOUS, numPrev);

    state.set(FIELD_NUM_NEXT, numNext);

    state.set(FIELD_NUM_RECORDS, NUMREC);

    state.set(FIELD_PREVIOUS_EXTENTS, extentsPrev);

    state.set(FIELD_NEXT_EXTENTS, extentsNext);

    state.set(FIELD_CURRENT_EXTENT, currentExtent);

  }

  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(FIELD_NUM_PREVIOUS).setMandatory(true);

      definition.addDynFieldInt(FIELD_NUM_NEXT).setMandatory(true);

      definition.addDynFieldInt(FIELD_NUM_RECORDS).setMandatory(true);

      definition.addDynFieldArray(FIELD_PREVIOUS_EXTENTS).setClassOfItems(Rectangle2D.class)

          .setMandatory(true);

      definition.addDynFieldArray(FIELD_NEXT_EXTENTS)

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

      definition.addDynFieldObject(FIELD_CURRENT_EXTENT)

      .setClassOfValue(Rectangle2D.class).setMandatory(false);

      return Boolean.TRUE;

    }

  }

}