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.form;
016    
017    import java.util.ArrayList;
018    import java.util.List;
019    
020    import org.apache.tapestry.IMarkupWriter;
021    import org.apache.tapestry.IRequestCycle;
022    import org.apache.tapestry.Tapestry;
023    import org.apache.tapestry.form.AbstractFormComponent;
024    import org.apache.tapestry.form.IPropertySelectionModel;
025    import org.apache.tapestry.form.ValidatableField;
026    import org.apache.tapestry.form.ValidatableFieldSupport;
027    import org.apache.tapestry.valid.ValidatorException;
028    
029    /**
030     * A component which uses <input type=checkbox> to set a property of some object. Typically,
031     * the values for the object are defined using an {@link org.apache.commons.lang.enum.Enum}. A
032     * MultiplePropertySelection is dependent on an {link IPropertySelectionModel} to provide the list
033     * of possible values.
034     * <p>
035     * Often, this is used to select one or more {@link org.apache.commons.lang.enum.Enum}to assign to
036     * a property; the {@link org.apache.tapestry.form.EnumPropertySelectionModel}class simplifies
037     * this.
038     * <p>
039     * The {@link org.apache.tapestry.contrib.palette.Palette}component is more powerful, but requires
040     * client-side JavaScript and is not fully cross-browser compatible.
041     * <p>
042     * <table border=1>
043     * <tr>
044     * <td>Parameter</td>
045     * <td>Type</td>
046     * <td>Direction</td>
047     * <td>Required</td>
048     * <td>Default</td>
049     * <td>Description</td>
050     * </tr>
051     * <tr>
052     * <td>selectedList</td>
053     * <td>java.util.List</td>
054     * <td>in-out</td>
055     * <td>yes</td>
056     * <td>&nbsp;</td>
057     * <td>The property to set. During rendering, this property is read, and sets the default value of
058     * the options in the select. When the form is submitted, list is cleared, then has each selected
059     * option added to it.</td>
060     * </tr>
061     * <tr>
062     * <td>renderer</td>
063     * <td>{@link IMultiplePropertySelectionRenderer}</td>
064     * <td>in</td>
065     * <td>no</td>
066     * <td>shared instance of {@link CheckBoxMultiplePropertySelectionRenderer}</td>
067     * <td>Defines the object used to render this component. The default renders a table of checkboxes.
068     * </td>
069     * </tr>
070     * <tr>
071     * <td>model</td>
072     * <td>{@link IPropertySelectionModel}</td>
073     * <td>in</td>
074     * <td>yes</td>
075     * <td>&nbsp;</td>
076     * <td>The model provides a list of possible labels, and matches those labels against possible
077     * values that can be assigned back to the property.</td>
078     * </tr>
079     * <tr>
080     * <td>disabled</td>
081     * <td>boolean</td>
082     * <td>in</td>
083     * <td>no</td>
084     * <td>false</td>
085     * <td>Controls whether the &lt;select&gt; is active or not. A disabled PropertySelection does not
086     * update its value parameter.
087     * <p>
088     * Corresponds to the <code>disabled</code> HTML attribute.</td>
089     * </tr>
090     * </table>
091     * <p>
092     * Informal parameters are not allowed.
093     * <p>
094     * As of 4.0, this component can be validated.
095     * 
096     * @author Sanjay Munjal
097     */
098    
099    public abstract class MultiplePropertySelection extends AbstractFormComponent implements ValidatableField
100    {
101        /**
102         * A shared instance of {@link CheckBoxMultiplePropertySelectionRenderer}.
103         */
104        public static final IMultiplePropertySelectionRenderer DEFAULT_CHECKBOX_RENDERER = new CheckBoxMultiplePropertySelectionRenderer();
105    
106        public abstract List getSelectedList();
107        
108        public abstract void setSelectedList(List selectedList);
109        
110        protected void finishLoad()
111        {
112            setRenderer(DEFAULT_CHECKBOX_RENDERER);
113        }
114    
115        protected void renderFormComponent(IMarkupWriter writer, IRequestCycle cycle)
116        {
117            List selectedList = getSelectedList();
118    
119            if (selectedList == null)
120                throw Tapestry.createRequiredParameterException(this, "selectedList");
121    
122            IPropertySelectionModel model = getModel();
123    
124            if (model == null)
125                throw Tapestry.createRequiredParameterException(this, "model");
126    
127            IMultiplePropertySelectionRenderer renderer = getRenderer();
128    
129            // Start rendering
130            renderer.beginRender(this, writer, cycle);
131    
132            int count = model.getOptionCount();
133    
134            for (int i = 0; i < count; i++)
135            {
136                Object option = model.getOption(i);
137    
138                // Try to find the option in the list and if yes, then it is checked.
139                boolean optionSelected = selectedList.contains(option);
140    
141                renderer.renderOption(this, writer, cycle, model, option, i, optionSelected);
142            }
143    
144            // A PropertySelection doesn't allow a body, so no need to worry about
145            // wrapped components.
146            renderer.endRender(this, writer, cycle);
147        }
148    
149        /**
150         * @see org.apache.tapestry.form.AbstractRequirableField#rewindFormComponent(org.apache.tapestry.IMarkupWriter, org.apache.tapestry.IRequestCycle)
151         */
152        protected void rewindFormComponent(IMarkupWriter writer, IRequestCycle cycle)
153        {
154            // get all the values
155            String[] optionValues = cycle.getParameters(getName());
156    
157            IPropertySelectionModel model = getModel();
158            
159            List selectedList = new ArrayList(getModel().getOptionCount());
160    
161            // Nothing was selected
162            if (optionValues != null)
163            {
164                // Go through the array and translate and put back in the list
165                for (int i = 0; i < optionValues.length; i++)
166                {
167                    // Translate the new value
168                    Object selectedValue = model.translateValue(optionValues[i]);
169    
170                    // Add this element in the list back
171                    selectedList.add(selectedValue);
172                }
173            }
174            
175            try
176            {
177                getValidatableFieldSupport().validate(this, writer, cycle, selectedList);
178                
179                setSelectedList(selectedList);
180            }
181            catch (ValidatorException e)
182            {
183                getForm().getDelegate().record(e);
184            }
185        }
186    
187        public abstract IPropertySelectionModel getModel();
188    
189        public abstract IMultiplePropertySelectionRenderer getRenderer();
190    
191        public abstract void setRenderer(IMultiplePropertySelectionRenderer renderer);
192        
193        public abstract ValidatableFieldSupport getValidatableFieldSupport();
194    
195        /**
196         * @see org.apache.tapestry.form.AbstractFormComponent#isRequired()
197         */
198        public boolean isRequired()
199        {
200            return getValidatableFieldSupport().isRequired(this);
201        }
202    }