// Copyright 2004, 2005 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.html;
import java.util.HashMap;
import java.util.Map;
import org.apache.hivemind.ApplicationRuntimeException;
import org.apache.tapestry.AbstractComponent;
import org.apache.tapestry.IAsset;
import org.apache.tapestry.IMarkupWriter;
import org.apache.tapestry.IRequestCycle;
import org.apache.tapestry.IScript;
import org.apache.tapestry.PageRenderSupport;
import org.apache.tapestry.Tapestry;
import org.apache.tapestry.TapestryUtils;
import org.apache.tapestry.components.ILinkComponent;
import org.apache.tapestry.components.LinkEventType;
/**
* Combines a link component (such as
* {@link org.apache.tapestry.link.DirectLink}) with an <img> and
* JavaScript code to create a rollover effect that works with both Netscape
* Navigator and Internet Explorer. [ <a
* href="../../../../../ComponentReference/Rollover.html">Component Reference
* </a>]
*
* @author Howard Lewis Ship
*/
public abstract class Rollover extends AbstractComponent
{
/**
* Converts an {@link IAsset}binding into a usable URL. Returns null if the
* binding does not exist or the binding's value is null.
*/
protected String getAssetURL(IAsset asset)
{
if (asset == null) return null;
return asset.buildURL();
}
protected void renderComponent(IMarkupWriter writer, IRequestCycle cycle)
{
// No body, so we skip it all if not rewinding (assumes no side effects
// on
// accessors).
if (cycle.isRewinding()) return;
String imageURL = null;
String mouseOverURL = null;
String mouseOutURL = null;
boolean dynamic = false;
String imageId = null;
PageRenderSupport pageRenderSupport = TapestryUtils
.getPageRenderSupport(cycle, this);
ILinkComponent serviceLink = (ILinkComponent) cycle
.getAttribute(Tapestry.LINK_COMPONENT_ATTRIBUTE_NAME);
if (serviceLink == null)
throw new ApplicationRuntimeException(Tapestry
.getMessage("Rollover.must-be-contained-by-link"), this,
null, null);
boolean linkDisabled = serviceLink.isDisabled();
if (linkDisabled)
{
imageURL = getAssetURL(getDisabled());
if (imageURL == null) imageURL = getAssetURL(getImage());
}
else
{
imageURL = getAssetURL(getImage());
mouseOverURL = getAssetURL(getMouseOver());
mouseOutURL = getAssetURL(getMouseOut());
dynamic = (mouseOverURL != null) || (mouseOutURL != null);
}
if (imageURL == null)
throw Tapestry.createRequiredParameterException(this, "image");
writer.beginEmpty("img");
writer.attribute("src", imageURL);
if (dynamic)
{
if (mouseOverURL == null) mouseOverURL = imageURL;
if (mouseOutURL == null) mouseOutURL = imageURL;
imageId = writeScript(cycle, pageRenderSupport, serviceLink,
mouseOverURL, mouseOutURL);
writer.attribute("id", imageId);
}
renderInformalParameters(writer, cycle);
writer.closeTag();
}
// Injected
public abstract IScript getScript();
private String writeScript(IRequestCycle cycle,
PageRenderSupport pageRenderSupport, ILinkComponent link,
String mouseOverImageURL, String mouseOutImageURL)
{
String imageId = pageRenderSupport.getUniqueString(getId());
String preloadedMouseOverImageURL = pageRenderSupport
.getPreloadedImageReference(mouseOverImageURL);
String preloadedMouseOutImageURL = pageRenderSupport
.getPreloadedImageReference(mouseOutImageURL);
Map symbols = new HashMap();
symbols.put("imageId", imageId);
symbols.put("mouseOverImageURL", preloadedMouseOverImageURL);
symbols.put("mouseOutImageURL", preloadedMouseOutImageURL);
getScript().execute(cycle, pageRenderSupport, symbols);
// Add attributes to the link to control mouse over/out.
// Because the script is written before the <body> tag,
// there won't be any timing issues (such as cause
// bug #113893).
link.addEventHandler(LinkEventType.MOUSE_OVER, (String) symbols
.get("onMouseOverName"));
link.addEventHandler(LinkEventType.MOUSE_OUT, (String) symbols
.get("onMouseOutName"));
return imageId;
}
public abstract IAsset getMouseOut();
public abstract IAsset getDisabled();
public abstract IAsset getMouseOver();
public abstract IAsset getImage();
}