Application: gvSIG desktop » Library: org.gvsig.tools

/* gvSIG. Geographic Information System of the Valencian Government

 *

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

 * of the Valencian Government (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.

 *

 */

package org.gvsig.tools.swing.impl.dynobject.set;

import org.gvsig.tools.ToolsLocator;

import org.gvsig.tools.dynobject.DynObject;

import org.gvsig.tools.dynobject.DynObjectPagingHelper;

import org.gvsig.tools.dynobject.DynObjectSet;

import org.gvsig.tools.exception.BaseException;

import org.gvsig.tools.observer.impl.BaseWeakReferencingObservable;

import org.gvsig.tools.swing.api.dynobject.set.JDynObjectSetComponent;

/**

 * Model for a {@link JDynObjectSetComponent}.

 * 

 * @author gvSIG Team

 * @version $Id$

 */

public class DynObjectSetModel extends BaseWeakReferencingObservable {

    public static final int DEFAULT_PAGE_SIZE = 10;

    private final DynObjectPagingHelper helper;

    private long currentPosition = 0;

    /**

     * Creates a new {@link DynObjectSetModel} with a {@link DynObjectSet} to

     * render.

     * 

     * @param set

     *            the data set to show

     * @throws BaseException

     *             if there is an error creating the model

     */

    public DynObjectSetModel(DynObjectSet set) throws BaseException {

        this(set, DEFAULT_PAGE_SIZE);

    }

    /**

     * Creates a new {@link DynObjectSetModel} with a {@link DynObjectSet} to

     * render.

     * 

     * @param set

     *            the data set to show

     * @param pageSize

     *            the size of the pages of data to preload

     * @throws BaseException

     *             if there is an error creating the model

     */

    public DynObjectSetModel(DynObjectSet set, int pageSize)

        throws BaseException {

        helper =

            ToolsLocator.getDynObjectManager().createDynObjectPagingHelper(set);

        helper.setMaxPageSize(pageSize);

    }

    /**

     * Moves the current position to the first one, if it is not already there.

     */

    public void first() {

        if (currentPosition != 0) {

            currentPosition = 0;

            notifyObservers();

        }

    }

    /**

     * Returns the {@link DynObject} at the current position.

     * 

     * @return the current DynObject

     * @throws BaseException

     *             if there is an error getting the DynObject

     */

    public DynObject getCurrentDynObject() throws BaseException {

        return helper.getDynObjectAt(currentPosition);

    }

    /**

     * Returns the position of the current element.

     * 

     * @return the current position

     */

    public long getCurrentPosition() {

        return currentPosition;

    }

    /**

     * Returns the {@link DynObjectSet} used by this model.

     * 

     * @return the DynObjectSet used by this model

     */

    public DynObjectSet getDynObjectSet() {

        return helper.getDynObjectSet();

    }

    /**

     * Returns the number of DynObjects.

     * 

     * @return the number of DynObjects

     */

    public long getSize() {

        return helper.getTotalSize();

    }

    /**

     * Returns if there are more DynObjects after the current one.

     * 

     * @return if there are following DynObjects

     */

    public boolean hasNext() {

        return currentPosition < helper.getTotalSize() - 1;

    }

    /**

     * Returns if there are more DynObjects before the current one.

     * 

     * @return if there are preceding DynObjects

     */

    public boolean hasPrevious() {

        return currentPosition > 0;

    }

    /**

     * Moves the current position to the last one, if it is not already there.

     */

    public void last() {

        long lastPosition = helper.getTotalSize() - 1;

        if (currentPosition != lastPosition) {

            currentPosition = lastPosition;

            notifyObservers();

        }

    }

    /**

     * Moves the current position to the next one, if it exists.

     */

    public void next() {

        if (hasNext()) {

            currentPosition++;

            notifyObservers();

        }

    }

    /**

     * Moves the current position to the previous one, if it exists.

     */

    public void previous() {

        if (hasPrevious()) {

            currentPosition--;

            notifyObservers();

        }

    }

}