// 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.hivemind.Resource;
import org.apache.tapestry.AbstractComponent;
import org.apache.tapestry.IAsset;
import org.apache.tapestry.IEngine;
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;
import org.apache.tapestry.engine.IScriptSource;
/**
* 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
{
private IScript _parsedScript;
/**
* 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, IRequestCycle cycle)
{
if (asset == null)
return null;
return asset.buildURL(cycle);
}
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 focusURL = null;
String blurURL = null;
boolean dynamic = false;
String imageName = 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(), cycle);
if (imageURL == null)
imageURL = getAssetURL(getImage(), cycle);
}
else
{
imageURL = getAssetURL(getImage(), cycle);
focusURL = getAssetURL(getFocus(), cycle);
blurURL = getAssetURL(getBlur(), cycle);
dynamic = (focusURL != null) || (blurURL != null);
}
if (imageURL == null)
throw Tapestry.createRequiredParameterException(this, "image");
writer.beginEmpty("img");
writer.attribute("src", imageURL);
writer.attribute("border", 0);
if (dynamic)
{
if (focusURL == null)
focusURL = imageURL;
if (blurURL == null)
blurURL = imageURL;
imageName = writeScript(cycle, pageRenderSupport, serviceLink, focusURL, blurURL);
writer.attribute("name", imageName);
}
renderInformalParameters(writer, cycle);
writer.closeTag();
}
private IScript getParsedScript()
{
if (_parsedScript == null)
{
IEngine engine = getPage().getEngine();
IScriptSource source = engine.getScriptSource();
Resource scriptLocation = getSpecification().getSpecificationLocation()
.getRelativeResource("Rollover.script");
_parsedScript = source.getScript(scriptLocation);
}
return _parsedScript;
}
private String writeScript(IRequestCycle cycle, PageRenderSupport pageRenderSupport,
ILinkComponent link, String focusURL, String blurURL)
{
String imageName = pageRenderSupport.getUniqueString(getId());
String focusImageURL = pageRenderSupport.getPreloadedImageReference(focusURL);
String blurImageURL = pageRenderSupport.getPreloadedImageReference(blurURL);
Map symbols = new HashMap();
symbols.put("imageName", imageName);
symbols.put("focusImageURL", focusImageURL);
symbols.put("blurImageURL", blurImageURL);
getParsedScript().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 imageName;
}
public abstract IAsset getBlur();
public abstract IAsset getDisabled();
public abstract IAsset getFocus();
public abstract IAsset getImage();
}