tapestry-framework/src/org/apache/tapestry/html/Body.java - tapestry3 - Git at Google

 //  Copyright 2004 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.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;

 import org.apache.tapestry.AbstractComponent;
 import org.apache.tapestry.ApplicationRuntimeException;
 import org.apache.tapestry.IMarkupWriter;
 import org.apache.tapestry.IRequestCycle;
 import org.apache.tapestry.IResourceLocation;
 import org.apache.tapestry.IScriptProcessor;
 import org.apache.tapestry.Tapestry;
 import org.apache.tapestry.asset.PrivateAsset;
 import org.apache.tapestry.resource.ClasspathResourceLocation;
 import org.apache.tapestry.util.IdAllocator;

 /**
  *  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 &lt;body&gt; tag).  This is currently used by {@link Rollover} and {@link Script}
  *  components.
  *
  *  [<a href="../../../../../ComponentReference/Body.html">Component Reference</a>]
  *
  *  @author Howard Lewis Ship
  *  @version $Id$
  *
  **/

 public abstract class Body extends AbstractComponent implements IScriptProcessor
 {
     // Lines that belong inside the onLoad event handler for the <body> tag.
     private StringBuffer _initializationScript;

     // The writer initially passed to render() ... wrapped elements render
     // into a nested response writer.

     private IMarkupWriter _outerWriter;

     // Any other scripting desired

     private StringBuffer _bodyScript;

     // Contains text lines related to image initializations

     private StringBuffer _imageInitializations;

     /**
      *  Map of URLs to Strings (preloaded image references).
      *
      **/

     private Map _imageMap;

     /**
      *  List of included scripts.  Values are Strings.
      *
      *  @since 1.0.5
      *
      **/

     private List _externalScripts;

     private IdAllocator _idAllocator;

     private static final String ATTRIBUTE_NAME = "org.apache.tapestry.active.Body";

     /**
      *  Tracks a particular preloaded image.
      *
      **/

     /**
      *  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)
     {
         if (_imageMap == null)
             _imageMap = new HashMap();

         String reference = (String) _imageMap.get(URL);

         if (reference == null)
         {
             int count = _imageMap.size();
             String varName = "tapestry_preload[" + count + "]";
             reference = varName + ".src";

             if (_imageInitializations == null)
                 _imageInitializations = new StringBuffer();

             _imageInitializations.append("  ");
             _imageInitializations.append(varName);
             _imageInitializations.append(" = new Image();\n");
             _imageInitializations.append("  ");
             _imageInitializations.append(reference);
             _imageInitializations.append(" = \"");
             _imageInitializations.append(URL);
             _imageInitializations.append("\";\n");

             _imageMap.put(URL, reference);
         }

         return reference;
     }

     /**
      *  Adds other initialization, in the form of additional JavaScript
      *  code to execute from the &lt;body&gt;'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)
     {
         if (_initializationScript == null)
             _initializationScript = new StringBuffer(script.length() + 1);

         _initializationScript.append(script);
         _initializationScript.append('\n');

     }

     /**
      *  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 &lt;body&gt; 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 &lt;script&gt; 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)
     {
         if (_bodyScript == null)
             _bodyScript = new StringBuffer(script.length());

         _bodyScript.append(script);
     }

     /**
      *  Used to include a script from an outside URL (the scriptLocation
      *  is a URL, probably obtained from an asset.  This adds
      *  an &lt;script src="..."&gt; tag before the main
      *  &lt;script&gt; tag.  The Body component ensures
      *  that each URL is included only once.
      *
      *  @since 1.0.5
      *
      **/

     public void addExternalScript(IResourceLocation scriptLocation)
     {
         if (_externalScripts == null)
             _externalScripts = new ArrayList();

         if (_externalScripts.contains(scriptLocation))
             return;

         // Alas, this won't give a good ILocation for the actual problem.

         if (!(scriptLocation instanceof ClasspathResourceLocation))
             throw new ApplicationRuntimeException(
                 Tapestry.format("Body.include-classpath-script-only", scriptLocation),
                 this,
                 null,
                 null);

         // Record the URL so we don't include it twice.

         _externalScripts.add(scriptLocation);
     }

     /**
      * Writes &lt;script&gt; elements for all the external scripts.
      */
     private void writeExternalScripts(IMarkupWriter writer)
     {
         int count = Tapestry.size(_externalScripts);
         for (int i = 0; i < count; i++)
         {
             ClasspathResourceLocation scriptLocation =
                 (ClasspathResourceLocation) _externalScripts.get(i);

             // This is still very awkward!  Should move the code inside PrivateAsset somewhere
             // else, so that an asset does not have to be created to to build the URL.
             PrivateAsset asset = new PrivateAsset(scriptLocation, null);
             String url = asset.buildURL(getPage().getRequestCycle());

             // Note: important to use begin(), not beginEmpty(), because browser don't
             // interpret <script .../> properly.

             writer.begin("script");
             writer.attribute("language", "JavaScript");
             writer.attribute("type", "text/javascript");
             writer.attribute("src", url);
             writer.end();
             writer.println();
         }

     }

     /**
      *  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.
      *
      **/

     public static Body get(IRequestCycle cycle)
     {
         return (Body) cycle.getAttribute(ATTRIBUTE_NAME);
     }

     protected void renderComponent(IMarkupWriter writer, IRequestCycle cycle)
     {
         if (cycle.getAttribute(ATTRIBUTE_NAME) != null)
             throw new ApplicationRuntimeException(
                 Tapestry.getMessage("Body.may-not-nest"),
                 this,
                 null,
                 null);

         cycle.setAttribute(ATTRIBUTE_NAME, this);

         _outerWriter = writer;

         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, including initialization.

         writeScript(_outerWriter);

         // Close the nested writer, which dumps its buffered content
         // into its parent.

         nested.close();

         writer.end(); // <body>

     }

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

         if (_idAllocator != null)
             _idAllocator.clear();

         if (_imageMap != null)
             _imageMap.clear();

         if (_externalScripts != null)
             _externalScripts.clear();

         if (_initializationScript != null)
             _initializationScript.setLength(0);

         if (_imageInitializations != null)
             _imageInitializations.setLength(0);

         if (_bodyScript != null)
             _bodyScript.setLength(0);

         _outerWriter = null;
     }

     /**
      *  Writes a single large JavaScript block containing:
      *  <ul>
      *  <li>Any image initializations
      *  <li>Any scripting
      *  <li>Any initializations
      *  </ul>
      *
      *  <p>The script is written into a nested markup writer.
      *
      *  <p>If there are any other initializations
      *  (see {@link #addInitializationScript(String)}),
      *  then a function to execute them is created.
      **/

     protected void writeScript(IMarkupWriter writer)
     {
         if (!Tapestry.isEmpty(_externalScripts))
             writeExternalScripts(writer);

         if (!(any(_initializationScript) || any(_bodyScript) || any(_imageInitializations)))
             return;

         writer.begin("script");
         writer.attribute("language", "JavaScript");
         writer.attribute("type", "text/javascript");
         writer.printRaw("<!--");

         if (any(_imageInitializations))
         {
             writer.printRaw("\n\nvar tapestry_preload = new Array();\n");
             writer.printRaw("if (document.images)\n");
             writer.printRaw("{\n");
             writer.printRaw(_imageInitializations.toString());
             writer.printRaw("}\n");
         }

         if (any(_bodyScript))
         {
             writer.printRaw("\n\n");
             writer.printRaw(_bodyScript.toString());
         }

         if (any(_initializationScript))
         {

             writer.printRaw("\n\n" + "window.onload = function ()\n" + "{\n");

             writer.printRaw(_initializationScript.toString());

             writer.printRaw("}");
         }

         writer.printRaw("\n\n// -->");
         writer.end();
     }

     private boolean any(StringBuffer buffer)
     {
         if (buffer == null)
             return false;

         return buffer.length() > 0;
     }

     public abstract String getElement();

     public abstract void setElement(String element);

     /**
      * 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)
     {
         if (_idAllocator == null)
             _idAllocator = new IdAllocator();

         return _idAllocator.allocateId(baseValue);
     }

 }
	// Copyright 2004 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.ArrayList;
	import java.util.HashMap;
	import java.util.List;
	import java.util.Map;

	import org.apache.tapestry.AbstractComponent;
	import org.apache.tapestry.ApplicationRuntimeException;
	import org.apache.tapestry.IMarkupWriter;
	import org.apache.tapestry.IRequestCycle;
	import org.apache.tapestry.IResourceLocation;
	import org.apache.tapestry.IScriptProcessor;
	import org.apache.tapestry.Tapestry;
	import org.apache.tapestry.asset.PrivateAsset;
	import org.apache.tapestry.resource.ClasspathResourceLocation;
	import org.apache.tapestry.util.IdAllocator;

	/**
	* 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
	* @version $Id$
	*
	**/

	public abstract class Body extends AbstractComponent implements IScriptProcessor
	{
	// Lines that belong inside the onLoad event handler for the <body> tag.
	private StringBuffer _initializationScript;

	// The writer initially passed to render() ... wrapped elements render
	// into a nested response writer.

	private IMarkupWriter _outerWriter;

	// Any other scripting desired

	private StringBuffer _bodyScript;

	// Contains text lines related to image initializations

	private StringBuffer _imageInitializations;

	/**
	* Map of URLs to Strings (preloaded image references).
	*
	**/

	private Map _imageMap;

	/**
	* List of included scripts. Values are Strings.
	*
	* @since 1.0.5
	*
	**/

	private List _externalScripts;

	private IdAllocator _idAllocator;

	private static final String ATTRIBUTE_NAME = "org.apache.tapestry.active.Body";

	/**
	* Tracks a particular preloaded image.
	*
	**/

	/**
	* 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)
	{
	if (_imageMap == null)
	_imageMap = new HashMap();

	String reference = (String) _imageMap.get(URL);

	if (reference == null)
	{
	int count = _imageMap.size();
	String varName = "tapestry_preload[" + count + "]";
	reference = varName + ".src";

	if (_imageInitializations == null)
	_imageInitializations = new StringBuffer();

	_imageInitializations.append(" ");
	_imageInitializations.append(varName);
	_imageInitializations.append(" = new Image();\n");
	_imageInitializations.append(" ");
	_imageInitializations.append(reference);
	_imageInitializations.append(" = \"");
	_imageInitializations.append(URL);
	_imageInitializations.append("\";\n");

	_imageMap.put(URL, reference);
	}

	return reference;
	}

	/**
	* 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)
	{
	if (_initializationScript == null)
	_initializationScript = new StringBuffer(script.length() + 1);

	_initializationScript.append(script);
	_initializationScript.append('\n');

	}

	/**
	* 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)
	{
	if (_bodyScript == null)
	_bodyScript = new StringBuffer(script.length());

	_bodyScript.append(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(IResourceLocation scriptLocation)
	{
	if (_externalScripts == null)
	_externalScripts = new ArrayList();

	if (_externalScripts.contains(scriptLocation))
	return;

	// Alas, this won't give a good ILocation for the actual problem.

	if (!(scriptLocation instanceof ClasspathResourceLocation))
	throw new ApplicationRuntimeException(
	Tapestry.format("Body.include-classpath-script-only", scriptLocation),
	this,
	null,
	null);

	// Record the URL so we don't include it twice.

	_externalScripts.add(scriptLocation);
	}

	/**
	* Writes <script> elements for all the external scripts.
	*/
	private void writeExternalScripts(IMarkupWriter writer)
	{
	int count = Tapestry.size(_externalScripts);
	for (int i = 0; i < count; i++)
	{
	ClasspathResourceLocation scriptLocation =
	(ClasspathResourceLocation) _externalScripts.get(i);

	// This is still very awkward! Should move the code inside PrivateAsset somewhere
	// else, so that an asset does not have to be created to to build the URL.
	PrivateAsset asset = new PrivateAsset(scriptLocation, null);
	String url = asset.buildURL(getPage().getRequestCycle());

	// Note: important to use begin(), not beginEmpty(), because browser don't
	// interpret <script .../> properly.

	writer.begin("script");
	writer.attribute("language", "JavaScript");
	writer.attribute("type", "text/javascript");
	writer.attribute("src", url);
	writer.end();
	writer.println();
	}

	}

	/**
	* 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.
	*
	**/

	public static Body get(IRequestCycle cycle)
	{
	return (Body) cycle.getAttribute(ATTRIBUTE_NAME);
	}

	protected void renderComponent(IMarkupWriter writer, IRequestCycle cycle)
	{
	if (cycle.getAttribute(ATTRIBUTE_NAME) != null)
	throw new ApplicationRuntimeException(
	Tapestry.getMessage("Body.may-not-nest"),
	this,
	null,
	null);

	cycle.setAttribute(ATTRIBUTE_NAME, this);

	_outerWriter = writer;

	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, including initialization.

	writeScript(_outerWriter);

	// Close the nested writer, which dumps its buffered content
	// into its parent.

	nested.close();

	writer.end(); // <body>

	}

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

	if (_idAllocator != null)
	_idAllocator.clear();

	if (_imageMap != null)
	_imageMap.clear();

	if (_externalScripts != null)
	_externalScripts.clear();

	if (_initializationScript != null)
	_initializationScript.setLength(0);

	if (_imageInitializations != null)
	_imageInitializations.setLength(0);

	if (_bodyScript != null)
	_bodyScript.setLength(0);

	_outerWriter = null;
	}

	/**
	* Writes a single large JavaScript block containing:
	* <ul>
	* <li>Any image initializations
	* <li>Any scripting
	* <li>Any initializations
	* </ul>
	*
	* <p>The script is written into a nested markup writer.
	*
	* <p>If there are any other initializations
	* (see {@link #addInitializationScript(String)}),
	* then a function to execute them is created.
	**/

	protected void writeScript(IMarkupWriter writer)
	{
	if (!Tapestry.isEmpty(_externalScripts))
	writeExternalScripts(writer);

	if (!(any(_initializationScript) \|\| any(_bodyScript) \|\| any(_imageInitializations)))
	return;

	writer.begin("script");
	writer.attribute("language", "JavaScript");
	writer.attribute("type", "text/javascript");
	writer.printRaw("<!--");

	if (any(_imageInitializations))
	{
	writer.printRaw("\n\nvar tapestry_preload = new Array();\n");
	writer.printRaw("if (document.images)\n");
	writer.printRaw("{\n");
	writer.printRaw(_imageInitializations.toString());
	writer.printRaw("}\n");
	}

	if (any(_bodyScript))
	{
	writer.printRaw("\n\n");
	writer.printRaw(_bodyScript.toString());
	}

	if (any(_initializationScript))
	{

	writer.printRaw("\n\n" + "window.onload = function ()\n" + "{\n");

	writer.printRaw(_initializationScript.toString());

	writer.printRaw("}");
	}

	writer.printRaw("\n\n// -->");
	writer.end();
	}

	private boolean any(StringBuffer buffer)
	{
	if (buffer == null)
	return false;

	return buffer.length() > 0;
	}

	public abstract String getElement();

	public abstract void setElement(String element);

	/**
	* 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)
	{
	if (_idAllocator == null)
	_idAllocator = new IdAllocator();

	return _idAllocator.allocateId(baseValue);
	}

	}