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.hivemind.HiveMind;
018    import org.apache.tapestry.AbstractComponent;
019    import org.apache.tapestry.IMarkupWriter;
020    import org.apache.tapestry.IRequestCycle;
021    
022    /**
023     * This component serves as a container for one item that is listed as a choice
024     * in a {@link Select}. A {@link Select}offers a selection of choices from
025     * which usersu may choose one or more items. The select list is created using a
026     * select element which contains a collection of option elements. A string or
027     * text describing the item appears between the opening and closing option tags.
028     * In order to have a dynamic onpick attribute it is better to use a concrete
029     * class of {@link org.apache.tapestry.link.ILinkRenderer}with the
030     * {@link OptionRenderer}.
031     * 
032     * @author David Solis
033     * @since 3.0
034     */
035    
036    public abstract class Option extends AbstractComponent
037    {
038    
039        /**
040         * @see org.apache.tapestry.AbstractComponent#renderComponent(IMarkupWriter,
041         *      IRequestCycle)
042         */
043    
044        protected void renderComponent(IMarkupWriter writer, IRequestCycle cycle)
045        {
046            boolean render = !cycle.isRewinding();
047    
048            if (render)
049            {
050                writer.begin("option");
051    
052                String value = getValue();
053                if (HiveMind.isNonBlank(value)) writer.attribute("value", value);
054    
055                renderInformalParameters(writer, cycle);
056    
057                renderBody(writer, cycle);
058    
059                writer.end();
060            }
061        }
062    
063        public abstract String getValue();
064    }