001    // Copyright May 4, 2006 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    package org.apache.tapestry.dojo.form;
015    
016    import org.apache.tapestry.IMarkupWriter;
017    import org.apache.tapestry.IRequestCycle;
018    import org.apache.tapestry.form.AbstractFormComponent;
019    
020    
021    /**
022     * Represents a dojo widget that manages an html form input
023     * field.
024     * 
025     * @author jkuhnert
026     * @since 4.1
027     */
028    public abstract class AbstractFormWidget extends AbstractFormComponent implements IFormWidget
029    {
030        
031        public abstract void setDestroy(boolean destroy);
032        
033        /**
034         * Determined dynamically at runtime during rendering, informs widget implementations
035         * if they should destroy their client side widget equivalents or leave them in tact.
036         * 
037         * @return True if the widget should be destroyed on this render, false otherwise.
038         */
039        public abstract boolean getDestroy();
040        
041        /**
042         * {@inheritDoc}
043         */
044        public void renderWidget(IMarkupWriter writer, IRequestCycle cycle)
045        {
046            renderComponent(writer, cycle);
047        }
048        
049        /**
050         * {@inheritDoc}
051         */
052        protected void renderFormComponent(IMarkupWriter writer, IRequestCycle cycle)
053        {
054            if(!cycle.isRewinding()) {
055    
056                if (!cycle.getResponseBuilder().isDynamic()
057                        || cycle.getResponseBuilder().explicitlyContains(this)) {
058    
059                    setDestroy(false);
060                } else {
061    
062                    setDestroy(true);
063                }
064            }
065            
066            renderFormWidget(writer, cycle);
067        }
068        
069        /**
070         * {@inheritDoc}
071         */
072        protected void rewindFormComponent(IMarkupWriter writer, IRequestCycle cycle)
073        {
074            rewindFormWidget(writer, cycle);
075        }
076        
077        /**
078         * Called when rendering a form widget. 
079         * 
080         * @param writer
081         *          The markup writer to render with.
082         * @param cycle
083         *          The cycle associated with request.
084         */
085        protected abstract void renderFormWidget(IMarkupWriter writer, IRequestCycle cycle);
086        
087        /**
088         * Called during form submission to retrieve submitted input values. 
089         * Components should do any validation/retrieval of values in this method. 
090         * 
091         * @param writer
092         *          The passed in {@link IMarkupWriter} will be a {@link org.apache.tapestry.engine.NullWriter}, making
093         *          any content written ignored. 
094         * @param cycle
095         *           Typically used to retrieve submitted value via <code>cycle.getParameter(getName())</code>.
096         */
097        protected abstract void rewindFormWidget(IMarkupWriter writer, IRequestCycle cycle);
098    }