source: trunk/gli/src/org/greenstone/gatherer/checklist/CheckList.java@ 4572

/**
 *#########################################################################
 *
 * 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.
 *########################################################################
 */

 




/* GPL_HEADER */
package org.greenstone.gatherer.checklist;
/**************************************************************************************
 * Title:        Gatherer
 * Description:  The Gatherer: a tool for gathering and enriching a digital collection.
 * Company:      The University of Waikato
 * Written:      14/08/02
 * Revised:      
 **************************************************************************************/
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.border.*;
import org.greenstone.gatherer.checklist.Entry;
/** 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
 */ 
// ####################################################################################
// Optimization                          Saving
// ####################################################################################
// Vector -> ArrayList                   + Processor
// ####################################################################################
public class CheckList
    extends JList {
    /** The border used when a list row is not in focus. */
    protected static Border noFocusBorder = new EmptyBorder(1, 1, 1, 1);
    /** Constructor. */
    public CheckList() {
    super();
    setCellRenderer(new CellRenderer());
    setModel(new DefaultListModel());
    setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
    addMouseListener(new CheckListListener());
    }
    /** Constructor.
     * @param list_data An ArrayList of entries for this checklist.
     * @see org.greenstone.gatherer.checklist.CheckList.Entry
     */
    public CheckList(ArrayList list_data) {
    super();
    // Create a new model.
    DefaultListModel model = new DefaultListModel();
    for(int i = 0; i < list_data.size(); i++) {
        Entry entry = null;
        Object temp = list_data.get(i);
        if(temp instanceof Entry) {
        entry = (Entry) temp;
        }
        else {
        entry = new Entry(list_data.get(i));
        }
        temp = null;
        String name = entry.toString();
        int index = 0;
        boolean found = false;
        while(index < model.size() && !found) {
        Object sibling = model.getElementAt(index);
        if(name.compareTo(sibling.toString()) <= 0) {
            model.add(index, entry);
            found = true;
        }
        index++;
        }
        if(!found) {
        model.addElement(entry);
        }
    }
    setModel(model);
    setCellRenderer(new CellRenderer());
    addMouseListener(new CheckListListener());
    setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
    }

    /** Constructor. */
    public CheckList(ListModel data_model) {
    super(data_model);
    setCellRenderer(new CellRenderer());
    addMouseListener(new CheckListListener());
    setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
    }

    public void addEntry(Entry entry) {
    DefaultListModel model = (DefaultListModel) getModel();
    String name = entry.toString();
    int index = 0;
    boolean found = false;
    while(index < model.size() && !found) {
        Object sibling = model.getElementAt(index);
        if(name.compareTo(sibling.toString()) <= 0) {
        model.add(index, entry);
        found = true;
        }
        index++;
        sibling = null;
    }
    if(!found) {
        model.addElement(entry);
    }         
    name = null;
    model = null;
    }

    public Entry get(int index) {
    DefaultListModel model = (DefaultListModel) getModel();
    return (Entry) model.get(index);
    }

    /** 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.CheckList.Entry
      */
    public ArrayList getSelected() {
    ArrayList result = new ArrayList();
    DefaultListModel model = (DefaultListModel) getModel();
    int size = model.size();
    for(int i = 0; i < size; i++) {
        Entry entry = (Entry) model.get(i);
        if(entry.isSelected()) {
        result.add(entry.getObject());
        }
    }
    return result;
    }

    public boolean isSelected(int index) {
    DefaultListModel model = (DefaultListModel) getModel();
    Entry entry = (Entry) model.get(index);
    return entry.isSelected();
    }

    public int getEntryCount() {
    return getModel().getSize();
    }

    /** Checks the entries in the list whose name appear in the given array.
      * @param names The name of entries to be checked as a <strong>String[]</strong>.
      * @see org.greenstone.gatherer.checklist.CheckList.Entry
      */
    public void setSelected(String names[]) {
    DefaultListModel model = (DefaultListModel) getModel();
    int size = model.size();
    for(int i = 0; i < size; i++) {
        Entry entry = (Entry) model.get(i);
        for(int j = 0; names != null && j < names.length; j++) {
        if(entry.toString().equals(names[j])) {
            entry.setSelected(true);
        }
        }
    }         
    }
    /** 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;
        checkbox.setBackground(is_selected ? list.getSelectionBackground() : list.getBackground());
        checkbox.setForeground(is_selected ? list.getSelectionForeground() : list.getForeground());
        checkbox.setEnabled(list.isEnabled());
        checkbox.setFont(list.getFont());
        checkbox.setFocusPainted(false);
        checkbox.setBorderPainted(true);
        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 {
    //private Entry previous_checkbox = null;
    /** 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 this is the same checkbox as was recently selected, change the tick.
        if (list.isSelectedIndex(index)) {
        if(!checkbox.isFixed()) {
            checkbox.setSelected(!checkbox.isSelected());
        }
        checkbox.grabFocus();
        }
        /*
          if(list.isSelectedIndex(index) && checkbox == previous_checkbox) {
          if(!checkbox.isFixed()) {
          checkbox.setSelected(!checkbox.isSelected());
          }
          checkbox.grabFocus();
          }
          // Otherwise the selection has just changed, so select the new checkbox
          else if(list.isSelectedIndex(index)) {
          previous_checkbox = checkbox;
          }
          else {
          previous_checkbox = null;
          }
        */
    }
    }
}