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
015package org.apache.tapestry.wml;
016
017import org.apache.hivemind.HiveMind;
018import org.apache.tapestry.AbstractComponent;
019import org.apache.tapestry.IMarkupWriter;
020import 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
034public 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}