001// Copyright 2004, 2005 The Apache Software Foundation
002//
003// Licensed under the Apache License, Version 2.0 (the "License");
004// you may not use this file except in compliance with the License.
005// You may obtain a copy of the License at
006//
007//     http://www.apache.org/licenses/LICENSE-2.0
008//
009// Unless required by applicable law or agreed to in writing, software
010// distributed under the License is distributed on an "AS IS" BASIS,
011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012// See the License for the specific language governing permissions and
013// limitations under the License.
014
015package org.apache.tapestry.contrib.palette;
016
017import java.util.ArrayList;
018import java.util.Collections;
019import java.util.Comparator;
020import java.util.List;
021
022import org.apache.tapestry.IMarkupWriter;
023import org.apache.tapestry.IRender;
024import org.apache.tapestry.IRequestCycle;
025
026/**
027 * One of the two columns in a Palette component: the left column lists available options, the right
028 * column lists the selected columns.
029 * 
030 * @author Howard Lewis Ship
031 */
032public class PaletteColumn implements IRender
033{
034    private String _name;
035
036    private String _clientId;
037
038    private int _rows;
039
040    private List _options = new ArrayList();
041
042    private static class ValueComparator implements Comparator
043    {
044        public int compare(Object o1, Object o2)
045        {
046            PaletteOption option1 = (PaletteOption) o1;
047            PaletteOption option2 = (PaletteOption) o2;
048
049            return option1.getValue().compareTo(option2.getValue());
050        }
051    }
052
053    private static class LabelComparator implements Comparator
054    {
055        public int compare(Object o1, Object o2)
056        {
057            PaletteOption option1 = (PaletteOption) o1;
058            PaletteOption option2 = (PaletteOption) o2;
059
060            return option1.getLabel().compareTo(option2.getLabel());
061        }
062    }
063
064    /**
065     * @param name
066     *            the name of the column (the name attribute of the <select>)
067     * @param rows
068     *            the number of visible rows (the size attribute of the <select>)
069     */
070    public PaletteColumn(String name, String clientId, int rows)
071    {
072        _name = name;
073        _clientId = clientId;
074        _rows = rows;
075    }
076
077    public void addOption(PaletteOption option)
078    {
079        _options.add(option);
080    }
081
082    /**
083     * Sorts the options by value (the hidden value for the option that represents the object
084     * value). This should be invoked before rendering this PaletteColumn.
085     */
086    public void sortByValue()
087    {
088        Collections.sort(_options, new ValueComparator());
089    }
090
091    /**
092     * Sorts the options by the label visible to the user. This should be invoked before rendering
093     * this PaletteColumn.
094     */
095    public void sortByLabel()
096    {
097        Collections.sort(_options, new LabelComparator());
098    }
099
100    /**
101     * Renders the <select> and <option> tags for this column.
102     */
103    public void render(IMarkupWriter writer, IRequestCycle cycle)
104    {
105        writer.begin("select");
106        writer.attribute("multiple", "multiple");
107        writer.attribute("name", _name);
108
109        if (_clientId != null)
110            writer.attribute("id", _clientId);
111
112        writer.attribute("size", _rows);
113        writer.println();
114
115        int count = _options.size();
116        for (int i = 0; i < count; i++)
117        {
118            PaletteOption o = (PaletteOption) _options.get(i);
119
120            o.render(writer, cycle);
121        }
122
123        writer.end();
124    }
125
126}