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