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.form;
016
017 import java.awt.Point;
018
019 import org.apache.tapestry.IAsset;
020 import org.apache.tapestry.IForm;
021 import org.apache.tapestry.IMarkupWriter;
022 import org.apache.tapestry.IRequestCycle;
023 import org.apache.tapestry.Tapestry;
024
025 /**
026 * Used to create an image button inside a {@link Form}. Although it is occasionally useful to know
027 * the {@link Point}on the image that was clicked (i.e., use the image as a kind of image map,
028 * which was the original intent of the HTML element), it is more commonly used to provide a graphic
029 * image for the user to click, rather than the rather plain <input type=submit>. [ <a
030 * href="../../../../../ComponentReference/ImageSubmit.html">Component Reference </a>]
031 *
032 * @author Howard Lewis Ship
033 */
034
035 public abstract class ImageSubmit extends Submit
036 {
037 /**
038 * @see org.apache.tapestry.form.AbstractFormComponent#setName(org.apache.tapestry.IForm)
039 */
040 protected void setName(IForm form)
041 {
042 String nameOverride = getNameOverride();
043
044 setName((nameOverride == null) ? form.getElementId(this) : form.getElementId(this, nameOverride));
045 }
046
047 protected boolean isClicked(IRequestCycle cycle, String name)
048 {
049 String parameterName = name + ".x";
050
051 return (cycle.getParameter(parameterName) != null);
052 }
053
054 protected void renderFormComponent(IMarkupWriter writer, IRequestCycle cycle)
055 {
056 boolean disabled = isDisabled();
057 IAsset disabledImage = getDisabledImage();
058
059 IAsset finalImage = (disabled && disabledImage != null) ? disabledImage : getImage();
060
061 String imageURL = finalImage.buildURL();
062
063 writer.beginEmpty("input");
064 writer.attribute("type", "image");
065 writer.attribute("name", getName());
066
067 if (disabled)
068 writer.attribute("disabled", "disabled");
069
070 // NN4 places a border unless you tell it otherwise.
071 // IE ignores the border attribute and never shows a border.
072
073 writer.attribute("border", 0);
074
075 writer.attribute("src", imageURL);
076
077 renderIdAttribute(writer, cycle);
078
079 renderInformalParameters(writer, cycle);
080
081 renderSubmitBindings(writer, cycle);
082
083 writer.closeTag();
084 }
085
086 void handleClick(IRequestCycle cycle, IForm form)
087 {
088 // The point parameter is not really used, unless the
089 // ImageButton is used for its original purpose (as a kind
090 // of image map). In modern usage, we only care about
091 // whether the user clicked on the image (and thus submitted
092 // the form), not where in the image the user actually clicked.
093
094 if (isParameterBound("point"))
095 {
096 int x = Integer.parseInt(cycle.getParameter(getName() + ".x"));
097 int y = Integer.parseInt(cycle.getParameter(getName() + ".y"));
098
099 setPoint(new Point(x, y));
100 }
101
102 super.handleClick(cycle, form);
103 }
104
105 /** parameter. */
106 public abstract IAsset getDisabledImage();
107
108 /** parameter. */
109 public abstract IAsset getImage();
110
111 /** parameter. */
112 public abstract String getNameOverride();
113
114 /** parameter. */
115 public abstract void setPoint(Point point);
116
117 protected void prepareForRender(IRequestCycle cycle)
118 {
119 super.prepareForRender(cycle);
120
121 if (getImage() == null)
122 throw Tapestry.createRequiredParameterException(this, "image");
123 }
124 }