Package org.apache.tapestry.form

Source Code of org.apache.tapestry.form.ImageSubmit

/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2000-2003 The Apache Software Foundation.  All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in
*    the documentation and/or other materials provided with the
*    distribution.
*
* 3. The end-user documentation included with the redistribution,
*    if any, must include the following acknowledgment:
*       "This product includes software developed by the
*        Apache Software Foundation (http://apache.org/)."
*    Alternately, this acknowledgment may appear in the software itself,
*    if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Apache" and "Apache Software Foundation", "Tapestry"
*    must not be used to endorse or promote products derived from this
*    software without prior written permission. For written
*    permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache"
*    or "Tapestry", nor may "Apache" or "Tapestry" appear in their
*    name, without prior written permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED.  IN NO EVENT SHALL THE TAPESTRY CONTRIBUTOR COMMUNITY
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation.  For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
*/

package org.apache.tapestry.form;

import java.awt.Point;

import org.apache.tapestry.IActionListener;
import org.apache.tapestry.IAsset;
import org.apache.tapestry.IBinding;
import org.apache.tapestry.IForm;
import org.apache.tapestry.IMarkupWriter;
import org.apache.tapestry.IRequestCycle;
import org.apache.tapestry.Tapestry;
import org.apache.tapestry.request.RequestContext;

/**
*  Used to create an image button inside a {@link Form}.  Although it
*  is occasionally useful to know the {@link Point} on the image that was clicked
*  (i.e., use the image as a kind of image map, which was the original intent
*  of the HTML element), it is more commonly used to provide a graphic
*  image for the user to click, rather than the rather plain &lt;input type=submit&gt;.
*
*  [<a href="../../../../../ComponentReference/ImageSubmit.html">Component Reference</a>]
*
*
@author Howard Lewis Ship
@version $Id: ImageSubmit.java,v 1.5 2003/04/16 16:43:17 hlship Exp $
**/

public abstract class ImageSubmit extends AbstractFormComponent
{

    public abstract IBinding getPointBinding();

    public abstract IBinding getSelectedBinding();

    protected void renderComponent(IMarkupWriter writer, IRequestCycle cycle)
    {
        IForm form = getForm(cycle);

        boolean rewinding = form.isRewinding();

        String nameOverride = getNameOverride();

        String name =
            nameOverride == null ? form.getElementId(this) : form.getElementId(this, nameOverride);

        if (rewinding)
        {
            // If disabled, do nothing.

            if (isDisabled())
                return;

            RequestContext context = cycle.getRequestContext();

            // Image clicks get submitted as two request parameters:
            // foo.x and foo.y

            String parameterName = name + ".x";

            String value = context.getParameter(parameterName);

            if (value == null)
                return;

            // The point parameter is not really used, unless the
            // ImageButton is used for its original purpose (as a kind
            // of image map).  In modern usage, we only care about
            // whether the user clicked on the image (and thus submitted
            // the form), not where in the image the user actually clicked.

            IBinding pointBinding = getPointBinding();

            if (pointBinding != null)
            {
                int x = Integer.parseInt(value);

                parameterName = name + ".y";
                value = context.getParameter(parameterName);

                int y = Integer.parseInt(value);

                pointBinding.setObject(new Point(x, y));
            }

            // Notify the application, by setting the select parameter
            // to the tag parameter.

            IBinding selectedBinding = getSelectedBinding();

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

            IActionListener listener = getListener();

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

            return;
        }

        // Not rewinding, do the real render

        boolean disabled = isDisabled();
        IAsset disabledImage = getDisabledImage();

        IAsset finalImage = (disabled && disabledImage != null) ? disabledImage : getImage();

        String imageURL = finalImage.buildURL(cycle);

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

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

        // NN4 places a border unless you tell it otherwise.
        // IE ignores the border attribute and never shows a border.

        writer.attribute("border", 0);

        writer.attribute("src", imageURL);

        renderInformalParameters(writer, cycle);

        writer.closeTag();
    }

    public abstract boolean isDisabled();

    public abstract IAsset getDisabledImage();

    public abstract IAsset getImage();

    public abstract IActionListener getListener();

    public abstract Object getTag();

    public abstract String getNameOverride();

    protected void prepareForRender(IRequestCycle cycle)
    {
        super.prepareForRender(cycle);

        if (getImage() == null)
            throw Tapestry.createRequiredParameterException(this, "image");
    }

}
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