tapestry-framework/src/org/apache/tapestry/form/Submit.java

//  Copyright 2004 The Apache Software Foundation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package org.apache.tapestry.form;

import org.apache.tapestry.IActionListener;
import org.apache.tapestry.IBinding;
import org.apache.tapestry.IForm;
import org.apache.tapestry.IMarkupWriter;
import org.apache.tapestry.IRequestCycle;


/**
 *  Implements a component that manages an HTML <input type=submit> form element.
 * 
 *  [<a href="../../../../../ComponentReference/Submit.html">Component Reference</a>]
 *
 *  <p>This component is generally only used when the form has multiple
 *  submit buttons, and it is important for the application to know
 *  which one was pressed.  You may also want to use
 *  {@link ImageSubmit} which accomplishes much the same thing, but uses
 *  a graphic image instead.
 *
 *
 *  @author Howard Lewis Ship
 *  @version $Id$
 * 
 **/

public abstract class Submit extends AbstractFormComponent{

    protected void renderComponent(IMarkupWriter writer, IRequestCycle cycle)
    {

        IForm form = getForm(cycle);
		
        boolean rewinding = form.isRewinding();

        String name = form.getElementId(this);

        if (rewinding)
        {
            // Don't bother doing anything if disabled.

            if (isDisabled())
                return;

            // How to know which Submit button was actually
            // clicked?  When submitted, it produces a request parameter
            // with its name and value (the value serves double duty as both
            // the label on the button, and the parameter value).

            String value = cycle.getRequestContext().getParameter(name);

            // If the value isn't there, then this button wasn't
            // selected.

            if (value == null)
                return;

            IBinding selectedBinding = getSelectedBinding();

            if (selectedBinding != null)
                selectedBinding.setObject(getTag());

            IActionListener listener = getListener();

            if (listener != null)
                listener.actionTriggered(this, cycle);

            return;
        }

        writer.beginEmpty("input");
        writer.attribute("type", "submit");
        writer.attribute("name", name);

        if (isDisabled())
            writer.attribute("disabled", "disabled");

        String label = getLabel();

        if (label != null)
            writer.attribute("value", label);

        renderInformalParameters(writer, cycle);

        writer.closeTag();
    }

    public abstract String getLabel();

    public abstract IBinding getSelectedBinding();

    public abstract boolean isDisabled();

    public abstract IActionListener getListener();

    public abstract Object getTag();

}