// 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 org.apache.hivemind.Resource;
import org.apache.tapestry.AbstractComponent;
import org.apache.tapestry.IMarkupWriter;
import org.apache.tapestry.IRequestCycle;
import org.apache.tapestry.PageRenderSupport;
import org.apache.tapestry.TapestryUtils;
import org.apache.tapestry.engine.IEngineService;
import org.apache.tapestry.util.PageRenderSupportImpl;
import org.apache.tapestry.web.WebResponse;
/**
* The body of a Tapestry page. This is used since it allows components on the page access to an
* initialization script (that is written the start, just inside the <body> tag). This is
* currently used by {@link Rollover}and {@link Script}components. [ <a
* href="../../../../../ComponentReference/Body.html">Component Reference </a>]
*
* @author Howard Lewis Ship
*/
public abstract class Body extends AbstractComponent implements PageRenderSupport
{
private PageRenderSupportImpl _pageRenderSupport;
/**
* Adds to the script an initialization for the named variable as an Image(), to the given URL.
* <p>
* Returns a reference, a string that can be used to represent the preloaded image in a
* JavaScript function.
*
* @since 1.0.2
*/
public String getPreloadedImageReference(String URL)
{
return _pageRenderSupport.getPreloadedImageReference(URL);
}
/**
* Adds other initialization, in the form of additional JavaScript code to execute from the
* <body>'s <code>onLoad</code> event handler. The caller is responsible for adding a
* semicolon (statement terminator). This method will add a newline after the script.
*/
public void addInitializationScript(String script)
{
_pageRenderSupport.addInitializationScript(script);
}
/**
* Adds additional scripting code to the page. This code will be added to a large block of
* scripting code at the top of the page (i.e., the before the <body> tag).
* <p>
* This is typically used to add some form of JavaScript event handler to a page. For example,
* the {@link Rollover}component makes use of this.
* <p>
* Another way this is invoked is by using the {@link Script}component.
* <p>
* The string will be added, as-is, within the <script> block generated by this
* <code>Body</code> component. The script should <em>not</em> contain HTML comments, those
* will be supplied by this Body component.
* <p>
* A frequent use is to add an initialization function using this method, then cause it to be
* executed using {@link #addInitializationScript(String)}.
*/
public void addBodyScript(String script)
{
_pageRenderSupport.addBodyScript(script);
}
/**
* Used to include a script from an outside URL (the scriptLocation is a URL, probably obtained
* from an asset. This adds an <script src="..."> tag before the main <script> tag.
* The Body component ensures that each URL is included only once.
*
* @since 1.0.5
*/
public void addExternalScript(Resource scriptLocation)
{
_pageRenderSupport.addExternalScript(scriptLocation);
}
/**
* Retrieves the <code>Body</code> that was stored into the request cycle. This allows
* components wrapped by the <code>Body</code> to locate it and access the services it
* provides.
*
* @deprecated To be removed in 4.1. Use
* {@link org.apache.tapestry.TapestryUtils#getPageRenderSupport(IRequestCycle)}
* instead.
*/
public static Body get(IRequestCycle cycle)
{
return (Body) TapestryUtils.getPageRenderSupport(cycle, null);
}
protected void prepareForRender(IRequestCycle cycle)
{
super.prepareForRender(cycle);
_pageRenderSupport = new PageRenderSupportImpl(getAssetService(), getResponse()
.getNamespace(), getLocation());
}
protected void renderComponent(IMarkupWriter writer, IRequestCycle cycle)
{
TapestryUtils.storePageRenderSupport(cycle, this);
IMarkupWriter nested = writer.getNestedWriter();
renderBody(nested, cycle);
// Start the body tag.
writer.println();
writer.begin(getElement());
renderInformalParameters(writer, cycle);
writer.println();
// Write the page's scripting. This is included scripts
// and dynamic JavaScript.
_pageRenderSupport.writeBodyScript(writer, cycle);
// Close the nested writer, which dumps its buffered content
// into its parent.
nested.close();
// Any initialization should go at the very end of the document
// just before the close body tag. Older version of Tapestry
// would create a window.onload event handler, but this is better
// (it doesn't have to wait for external images to load).
_pageRenderSupport.writeInitializationScript(writer);
writer.end(); // <body>
}
protected void cleanupAfterRender(IRequestCycle cycle)
{
super.cleanupAfterRender(cycle);
_pageRenderSupport = null;
TapestryUtils.removePageRenderSupport(cycle);
}
public abstract String getElement();
public abstract void setElement(String element);
/**
* Injected
*
* @since 4.0
*/
public abstract IEngineService getAssetService();
/**
* Injected
*
* @since 4.0
*/
public abstract WebResponse getResponse();
/**
* Sets the element parameter property to its default, "body".
*
* @since 3.0
*/
protected void finishLoad()
{
setElement("body");
}
/** @since 3.0 */
public String getUniqueString(String baseValue)
{
return _pageRenderSupport.getUniqueString(baseValue);
}
}