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.form;
016
017import org.apache.tapestry.IMarkupWriter;
018import org.apache.tapestry.IRequestCycle;
019
020/**
021 * Implements a component that manages an HTML &lt;input type=button&gt; form element. [ <a
022 * href="../../../../../ComponentReference/Button.html">Component Reference </a>]
023 * <p>
024 * This component is useful for attaching JavaScript onclick event handlers.
025 * 
026 * @author Howard Lewis Ship
027 * @author Paul Geerts
028 * @author Malcolm Edgar
029 * @author Paul Ferraro
030 */
031public abstract class Button extends AbstractFormComponent
032{
033    /**
034     * @see org.apache.tapestry.form.AbstractFormComponent#renderFormComponent(org.apache.tapestry.IMarkupWriter,
035     *      org.apache.tapestry.IRequestCycle)
036     */
037    protected void renderFormComponent(IMarkupWriter writer, IRequestCycle cycle)
038    {
039        writer.begin("button");
040        writer.attribute("type", "button");
041        writer.attribute("name", getName());
042
043        if (isDisabled())
044        {
045            writer.attribute("disabled", "disabled");
046        }
047
048        renderIdAttribute(writer, cycle);
049
050        renderInformalParameters(writer, cycle);
051
052        String label = getLabel();
053
054        if (label != null)
055            writer.print(label);
056        else
057            renderBody(writer, cycle);
058
059        writer.end();
060    }
061
062    /**
063     * @see org.apache.tapestry.form.AbstractFormComponent#rewindFormComponent(org.apache.tapestry.IMarkupWriter, org.apache.tapestry.IRequestCycle)
064     */
065    protected void rewindFormComponent(IMarkupWriter writer, IRequestCycle cycle)
066    {
067        // Do nothing
068    }
069
070    /**
071     * @see org.apache.tapestry.form.IFormComponent#getClientId()
072     */
073    public String getClientId()
074    {
075        return null;
076    }
077
078    /**
079     * @see org.apache.tapestry.form.IFormComponent#getDisplayName()
080     */
081    public String getDisplayName()
082    {
083        return null;
084    }
085
086    /**
087     * @see org.apache.tapestry.form.IFormComponent#isDisabled()
088     */
089    public boolean isDisabled()
090    {
091        return false;
092    }
093
094    public abstract String getLabel();
095}