PagingPanel.java

/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2006, Red Hat Middleware LLC, and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.jboss.bpm.console.client.common;

import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;
import com.google.gwt.user.client.ui.Button;
import org.gwt.mosaic.ui.client.Caption;
import org.gwt.mosaic.ui.client.layout.BoxLayout;
import org.gwt.mosaic.ui.client.layout.MosaicPanel;
import org.gwt.mosaic.ui.client.util.ButtonHelper;

import java.util.ArrayList;
import java.util.List;

/**
 * Cheap paging helper
 *
 * @author Heiko.Braun <heiko.braun@jboss.com>
 */
public class PagingPanel extends MosaicPanel
{

  private PagingCallback callback;
  private int limit = 12;
  private int page = 0;

  private boolean leftBounds = true;
  private boolean rightBounds;

  private Button revBtn;
  private Button ffwBtn;

  public PagingPanel(final PagingCallback callback)
  {
    super(new BoxLayout(BoxLayout.Orientation.HORIZONTAL));
    setStyleName("bpm-paging-panel");

    this.callback = callback;

    ClickHandler clickHandler = new ClickHandler()
    {
      public void onClick(ClickEvent clickEvent)
      {
        page--;
        rightBounds = false;
        callback.rev();
      }
    };
    revBtn = new Button(
        ButtonHelper.createButtonLabel(
            Caption.IMAGES.toolCollapseLeft(),"",
            ButtonHelper.ButtonLabelType.NO_TEXT),
        clickHandler
    );

    this.add(revBtn);

    ClickHandler clickHandler2 = new ClickHandler()
    {
      public void onClick(ClickEvent clickEvent)
      {
        page++;
        leftBounds = false;
        callback.ffw();
      }
    };

    ffwBtn = new Button(
        ButtonHelper.createButtonLabel(
            Caption.IMAGES.toolCollapseRight(),"",
            ButtonHelper.ButtonLabelType.NO_TEXT),
        clickHandler2
    );

    this.add(ffwBtn);
  }

  public void reset()
  {
    leftBounds=true;
    rightBounds=false;
    page = 0;
  }

  public List trim(List tmp)
  {
    List trimmed = new ArrayList();

    int size = tmp.size();
    if(limit>=size)
    {
      trimmed = tmp;
      rightBounds=true;
    }
    else
    {

      // leftbounds
      if(page<=0)
      {
        page=0;
        leftBounds=true;
      }

      int begin = 0;
      int end = 0;

      // rightbounds
      if(page*limit>=size)
      {
        begin = (page-1)*limit;
        rightBounds=true;
      }
      else
        begin = page*limit;

      if(begin+limit>=size)
      {
        end = size;
        rightBounds=true;
      }
      else
        end = begin+limit;

      // select range
      int i=0;
      for(Object o : tmp)
      {
        if(i>=begin && i<end) trimmed.add(o);
        i++;
      }

    }

    revBtn.setEnabled(!leftBounds);
    ffwBtn.setEnabled(!rightBounds);

    return trimmed;
  }
}