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    
015    package org.apache.tapestry.contrib.palette;
016    
017    import java.util.ArrayList;
018    import java.util.Collections;
019    import java.util.Comparator;
020    import java.util.List;
021    
022    import org.apache.tapestry.IMarkupWriter;
023    import org.apache.tapestry.IRender;
024    import 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     */
032    public 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    }