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.AbstractFormComponent;
020    
021    /**
022     * A base class for building components that correspond to WML postfield elements. All such
023     * components must be wrapped (directly or indirectly) by a {@link Go}component.
024     * 
025     * @author David Solis
026     * @since 3.0
027     */
028    
029    public abstract class AbstractPostfield extends AbstractFormComponent
030    {
031        /**
032         * @see org.apache.tapestry.form.AbstractFormComponent#renderFormComponent(org.apache.tapestry.IMarkupWriter, org.apache.tapestry.IRequestCycle)
033         */
034        protected void renderFormComponent(IMarkupWriter writer, IRequestCycle cycle)
035        {
036            writer.beginEmpty("postfield");
037    
038            writer.attribute("name", getName());
039    
040            String varName = getVarName();
041            writer.attributeRaw("value", varName != null ? getEncodedVarName(varName) : "");
042    
043            renderInformalParameters(writer, cycle);
044    
045            writer.closeTag();
046        }
047    
048        private String getEncodedVarName(String varName)
049        {
050            return "$(" + varName + ")";
051        }
052    
053        public boolean isDisabled()
054        {
055            return false;
056        }
057    
058        public abstract String getVarName();
059    
060        public void updateValue(Object value)
061        {
062            getBinding("value").setObject(value);
063        }
064    }