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.wml;
016    
017    import org.apache.tapestry.IMarkupWriter;
018    import org.apache.tapestry.IRequestCycle;
019    import org.apache.tapestry.form.IPropertySelectionModel;
020    
021    /**
022     * SelectionField specifies a postfield element and it is used to complement the
023     * {@link PropertySelection}component.
024     * 
025     * @author David Solis
026     * @since 3.0
027     */
028    public abstract class SelectionField extends AbstractPostfield
029    {
030    
031        /**
032         * @see org.apache.tapestry.form.AbstractFormComponent#rewindFormComponent(org.apache.tapestry.IMarkupWriter,
033         *      org.apache.tapestry.IRequestCycle)
034         */
035        protected void rewindFormComponent(IMarkupWriter writer, IRequestCycle cycle)
036        {
037            String optionValue = cycle.getParameter(getName());
038            IPropertySelectionModel model = getModel();
039            Object value = (optionValue == null) ? null : model
040                    .translateValue(optionValue);
041    
042            updateValue(value);
043        }
044    
045        public abstract IPropertySelectionModel getModel();
046    }