tilesutilimpl.java

这是一个轻便的j2ee的web应用框架,是一个在多个项目中运用的实际框架,采用struts,hebinate,xml等技术,有丰富的tag,role,navigation,session,dictio

/*
 * $Header: /sfroot/cvs/esimple/src/core/org/apache/struts/tiles/TilesUtilImpl.java,v 1.1.1.1 2004/09/08 06:38:37 lava Exp $
 * $Revision: 1.1.1.1 $
 * $Date: 2004/09/08 06:38:37 $
 *
 * ====================================================================
 *
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999-2003 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Struts", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact [e-mail].
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 * 5. Products derived from this software may not be called "Apache"
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 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package org.apache.struts.tiles;

import java.io.IOException;
import java.io.Serializable;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.jsp.PageContext;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.struts.tiles.definition.ComponentDefinitionsFactoryWrapper;
import org.apache.struts.util.RequestUtils;

  /**
   * Default implementation of TilesUtil.
   * This class contains default implementation of utilities. This implementation
   * is intended to be used without Struts.
   */
public class TilesUtilImpl implements Serializable
{
     /** Commons Logging instance.*/
  protected Log log = LogFactory.getLog(TilesUtil.class);

    /** Constant name used to store factory in servlet context */
  public static final String DEFINITIONS_FACTORY = "org.apache.struts.tiles.DEFINITIONS_FACTORY";

    /**
     * Do a forward using request dispatcher.
     *
     * This method is used by the Tiles package anytime a forward is required.
     * @param uri Uri or Definition name to forward.
     * @param request Current page request.
     * @param servletContext Current servlet context.
     */
  public void doForward(String uri, HttpServletRequest request, HttpServletResponse response,
                        ServletContext servletContext)
    throws IOException, ServletException
  {
  request.getRequestDispatcher( uri ).forward(request, response);
  }

    /**
     * Do an include using request dispatcher.
     *
     * This method is used by the Tiles package when an include is required.
     * The Tiles package can use indifferently any form of this method.
     * @param uri Uri or Definition name to forward.
     * @param request Current page request.
     * @param response Current page response.
     * @param servletContext Current servlet context.
     */
  public void doInclude(String uri, HttpServletRequest request, HttpServletResponse response,
                        ServletContext servletContext)
    throws IOException, ServletException
  {
  request.getRequestDispatcher( uri ).include(request, response);
  }

    /**
     * Do an include using PageContext.include().
     *
     * This method is used by the Tiles package when an include is required.
     * The Tiles package can use indifferently any form of this method.
     * @param uri Uri or Definition name to forward.
     * @param request Current page request.
     * @param response Current page response.
     * @param servletContext Current servlet context.
     */
  public static void doInclude(String uri, PageContext pageContext)
        throws IOException, ServletException
  {
  pageContext.include(uri);
  }

    /**
     * Get definition factory from appropriate servlet context.
     * @return Definitions factory or <code>null</code> if not found.
     */
  public DefinitionsFactory getDefinitionsFactory(ServletRequest request, ServletContext servletContext)
  {
  return (DefinitionsFactory)servletContext.getAttribute(DEFINITIONS_FACTORY);
  }

    /**
     * Create Definition factory from specified configuration object.
     * Create an instance of the factory with the class specified in the config
     * object. Then, initialize this factory and finally store the factory in
     * appropriate context by calling
     * {@link #makeDefinitionsFactoryAccessible(DefinitionsFactory, ServletContext)}.
     * Factory creation is done by {@link #createDefinitionFactoryInstance(String)}.
     * <p>
     *
     * @param servletContext Servlet Context passed to newly created factory.
     * @param factoryConfig Configuration object passed to factory.
     * @return newly created factory of type specified in the config object.
     * @throws DefinitionsFactoryException If an error occur while initializing factory
     */
  public DefinitionsFactory createDefinitionsFactory(ServletContext servletContext, DefinitionsFactoryConfig factoryConfig)
    throws DefinitionsFactoryException
  {
      // Create configurable factory
    DefinitionsFactory factory = createDefinitionFactoryInstance(factoryConfig.getFactoryClassname());
    factory.init( factoryConfig, servletContext );
      // Make factory accessible from jsp tags (push it in appropriate context)
    makeDefinitionsFactoryAccessible(factory, servletContext );
    return factory;
  }

  /**
   * Create Definition factory of specified classname.
   * Factory class must extend the {@link DefinitionsFactory} class.
   * The factory is wrapped appropriately with {@link ComponentDefinitionsFactoryWrapper}
   * if it is an instance of the deprecated ComponentDefinitionsFactory class.
   * @param classname Class name of the factory to create.
   * @return newly created factory.
   * @throws DefinitionsFactoryException If an error occur while initializing factory
   */
  protected DefinitionsFactory createDefinitionFactoryInstance(String classname)
    throws DefinitionsFactoryException
  {
  try
    {
    Class factoryClass = applicationClass(classname);
    Object factory = factoryClass.newInstance();

      // Backward compatibility : if factory classes implements old interface,
      // provide appropriate wrapper
    if( factory instanceof ComponentDefinitionsFactory )
      {
      factory = new ComponentDefinitionsFactoryWrapper( (ComponentDefinitionsFactory)factory );
      } // end if
    return (DefinitionsFactory)factory;
    }
   catch( ClassCastException ex )
    { // Bad classname
    throw new DefinitionsFactoryException( "Error - createDefinitionsFactory : Factory class '"
                                           + classname +" must implement 'TilesDefinitionsFactory'.", ex );
    }
   catch( ClassNotFoundException ex )
    { // Bad classname
    throw new DefinitionsFactoryException( "Error - createDefinitionsFactory : Bad class name '"
                                           + classname +"'.", ex );
    }
   catch( InstantiationException ex )
    { // Bad constructor or error
    throw new DefinitionsFactoryException( ex );
    }
   catch( IllegalAccessException ex )
    { //
    throw new DefinitionsFactoryException( ex );
    }
  }
  /**
   * Make definition factory accessible to Tags.
   * Factory is stored in servlet context.
   * @param factory Factory to be made accessible.
   * @param servletContext Current servlet context.
   */
 protected void makeDefinitionsFactoryAccessible(DefinitionsFactory factory, ServletContext servletContext)
  {
  servletContext.setAttribute(DEFINITIONS_FACTORY, factory);
  }

    /**
     * Return the <code>Class</code> object for the specified fully qualified
     * class name from the underlying class loader.
     *
     * @param className Fully qualified class name to be loaded.
     * @return Class object.
     * @exception ClassNotFoundException if the class cannot be found
     * @deprecated Use RequestUtils.applicationClass() instead.
     */
  public Class applicationClass(String className) throws ClassNotFoundException
  {
    return RequestUtils.applicationClass(className);
  }

}