source: trunk/gli/src/org/greenstone/gatherer/checklist/CheckList.java@ 8496

/**
 *#########################################################################
 *
 * A component of the Gatherer application, part of the Greenstone digital
 * library suite from the New Zealand Digital Library Project at the
 * University of Waikato, New Zealand.
 *
 * <BR><BR>
 *
 * Author: John Thompson, Greenstone Digital Library, University of Waikato
 *
 * <BR><BR>
 *
 * Copyright (C) 1999 New Zealand Digital Library Project
 *
 * <BR><BR>
 *
 * 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.
 *
 * <BR><BR>
 *
 * 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.
 *
 * <BR><BR>
 *
 * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 *########################################################################
 */
package org.greenstone.gatherer.checklist;

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.border.*;


/** This class provides a visual component that has the form of a list, as provided by JList but uses JCheckBox for data selection. Thus several elements can be 'ticked' in the list, and this selection returned using the method getSelected().<BR>Parts of this code modified from Trevor Harmon's posting on www.dejanews.com.
 * @author John Thompson
 * @version 2.3
 */ 
public class CheckList
    extends JList
{
    /** The border used when a list row is not in focus. */
    static private Border noFocusBorder = new EmptyBorder(1, 1, 1, 1);

    private boolean show_selected_row = true;


    /** Constructor. */
    public CheckList(boolean show_selected_row)
    {
    super();
    this.show_selected_row = show_selected_row;

    setCellRenderer(new CellRenderer());
    setModel(new DefaultListModel());
    setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
    addMouseListener(new CheckListListener());
    }


    public void addEntry(Entry entry)
    {
    DefaultListModel model = (DefaultListModel) getModel();

    // Add the entry in alpabetical order
    String name = entry.toString();
    for (int i = 0; i < model.size(); i++) {
        Object sibling = model.getElementAt(i);
        if (name.compareTo(sibling.toString()) <= 0) {
        model.add(i, entry);
        return;
        }
    }

    model.addElement(entry);
    }


    public void clearSelection()
    {
    DefaultListModel model = (DefaultListModel) getModel();
    for (int i = 0; i < model.size(); i++) {
        ((Entry) model.get(i)).setSelected(false);
    }
    updateUI();
    }


    /** Retrieve the currently ticked entries from this list.
     * @return An <strong>ArrayList</strong> containing only those entries from the initial list that are checked.
     * @see org.greenstone.gatherer.checklist.Entry
     */
    public ArrayList getSelected()
    {
    ArrayList result = new ArrayList();
    DefaultListModel model = (DefaultListModel) getModel();
    for (int i = 0; i < model.size(); i++) {
        Entry entry = (Entry) model.get(i);
        if (entry.isSelected()) {
        result.add(entry.getObject());
        }
    }
    return result;
    }


//     public boolean isSelectionEmpty()
//     {
//  System.err.println("In CheckList.isSelectionEmpty()...");
//  DefaultListModel model = (DefaultListModel) getModel();
//  for (int i = 0; i < model.size(); i++) {
//      Entry entry = (Entry) model.get(i);
//      if (entry.isSelected()) {
//      return false;
//      }
//  }

//  return true;
//     }


    public void setListData(ArrayList list_data)
    {
    // Create a new model.
    setModel(new DefaultListModel());

    // Add the items from the list to the model
    for (int i = 0; i < list_data.size(); i++) {
        Object list_object = list_data.get(i);
        if (list_object instanceof Entry) {
        addEntry((Entry) list_object);
        }
        else {
        addEntry(new Entry(list_object));
        }
    }
    }


    public void setSelectedObjects(Object objects[])
    {
    if (objects == null) {
        return;
    }

    DefaultListModel model = (DefaultListModel) getModel();
    for (int i = 0; i < model.size(); i++) {
        Entry entry = (Entry) model.get(i);
        for (int j = 0; j < objects.length; j++) {
        if (entry.getObject().equals(objects[j])) {
            entry.setSelected(true);
        }
        }
    }
    updateUI();
    }


    private void selectionChanged(int index) {
    fireSelectionValueChanged(index, index, false);
    }


    /** A custom list cell renderer for producing rows which contain clickable check boxes. */
    protected class CellRenderer 
    implements ListCellRenderer {

    /** Return a component that has been configured to display the specified value. That component's paint method is then called to "render" the cell. If it is necessary to compute the dimensions of a list because the list cells do not have a fixed size, this method is called to generate a component on which getPreferredSize  can be invoked.
     * @param list The </strong>JList</strong> we're painting.
     * @param value The value returned by list.getModel().getElementAt(index), as an <strong>Object</strong>.
     * @param index The cells index as an <i>int</i>.
     * @param is_selected <i>true</i> if the specified cell was selected, <i>false</i> otherwise.
     * @param cell_has_focus <i>true</i> if and only if the specified cell has the focus.
     * @return A <strong>Component</strong> whose paint() method will render the specified value.
     */
    public Component getListCellRendererComponent(JList list, Object value, int index, boolean is_selected, boolean cell_has_focus) {
        JCheckBox checkbox = (JCheckBox) value;
        if(show_selected_row) {
        checkbox.setBackground(is_selected ? list.getSelectionBackground() : list.getBackground());
        checkbox.setForeground(is_selected ? list.getSelectionForeground() : list.getForeground());
        checkbox.setBorderPainted(true);
        }
        else {
        checkbox.setBackground(list.getBackground());
        checkbox.setForeground(list.getForeground());
        checkbox.setBorderPainted(false);
        }
        checkbox.setEnabled(list.isEnabled());
        checkbox.setFont(list.getFont());
        checkbox.setFocusPainted(false);
        checkbox.setBorder((is_selected) ? UIManager.getBorder("List.focusCellHighlightBorder") : noFocusBorder);
        return checkbox;
    }
    }


    /** Listens for clicks apon the checks within the list, and updates as necessary. */
    private class CheckListListener 
    extends MouseAdapter {

    /** Called whenever the mouse is clicked over our list. We find the nearest checkbox and change its state.
     * @param e A <strong>MouseEvent</strong> containing everything you ever wanted to know about the mouse event but were afraid to ask.
     */
    public void mousePressed(MouseEvent e) {
        JList list = (JList) e.getSource();
        int index = list.locationToIndex(e.getPoint());
        Entry checkbox = (Entry)list.getModel().getElementAt(index);
        if(!checkbox.isFixed()) {
        checkbox.setSelected(!checkbox.isSelected());
        }
        checkbox.grabFocus();
        // Fire a selection changed event
        selectionChanged(index);
    }
    }
}