tilesplugin.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/TilesPlugin.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
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 *    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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package org.apache.struts.tiles;

import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.UnavailableException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.struts.action.ActionServlet;
import org.apache.struts.action.PlugIn;
import org.apache.struts.action.RequestProcessor;
import org.apache.struts.config.ControllerConfig;
import org.apache.struts.config.ModuleConfig;
import org.apache.struts.config.PlugInConfig;
import org.apache.struts.util.RequestUtils;

/**
 * Tiles Plugin used to initialize Tiles.
 * This plugin is to be used with Struts 1.1 in association with
 * {@link TilesRequestProcessor}.
 * <br>
 * This plugin creates one definition factory for each Struts-module. The definition factory
 * configuration is read first from 'web.xml' (backward compatibility), then it is
 * overloaded with values found in the plugin property values.
 * <br>
 * The plugin changes the Struts configuration by specifying a {@link TilesRequestProcessor} as
 * request processor. If you want to use your own RequestProcessor,
 * it should subclass TilesRequestProcessor.
 * <br>
 * This plugin can also be used to create one single factory for all modules.
 * This behavior is enabled by specifying <code>moduleAware=false</code> in each
 * plugin properties. In this case, the definition factory
 * configuration file is read by the first Tiles plugin to be initialized. The order is
 * determined by the order of modules declaration in web.xml. The first module
 * is always the default one if it exists.
 * The plugin should be declared in each struts-config.xml file in order to
 * properly initialize the request processor.
 * @author Cedric Dumoulin
 * @since 1.1
 */
public class TilesPlugin implements PlugIn {

      /** Commons Logging instance. */
    protected static Log log = LogFactory.getLog(TilesPlugin.class);

      /** Is the factory module aware ? */
    protected boolean moduleAware = false;

      /** Tiles util implementation classname. This property can be set
       *  by user in the plugin declaration
       */
    protected String tilesUtilImplClassname = null;

      /** Associated definition factory */
    protected DefinitionsFactory definitionFactory;

      /** The plugin config object provided by the ActionServlet initializing
       *  this plugin.
       */
    protected PlugInConfig currentPlugInConfigObject;

    /**
     * Get the module aware flag.
     * @return <code>true</code>: user wants a single factory instance,
     * <code>false:</code> user wants multiple factory instances (one per module with Struts)
     */
    public boolean isModuleAware() {
        return moduleAware;
    }

    /**
     * Set the module aware flag.
     * This flag is only meaningful if the property <code>tilesUtilImplClassname</code> is not
     * set.
     * @param moduleAware <code>true</code>: user wants a single factory instance,
     * <code>false:</code> user wants multiple factory instances (one per module with Struts)
     */
    public void setModuleAware(boolean moduleAware) {
        this.moduleAware = moduleAware;
    }

    /**
     * <p>Receive notification that the specified module is being
     * started up.</p>
     *
     * @param servlet ActionServlet that is managing all the modules
     *  in this web application.
     * @param moduleConfig ModuleConfig for the module with which
     *  this plugin is associated.
     *
     * @exception ServletException if this <code>PlugIn</code> cannot
     *  be successfully initialized.
     */
    public void init(ActionServlet servlet, ModuleConfig moduleConfig) throws ServletException
    {
      // Create factory config object
    DefinitionsFactoryConfig factoryConfig = readFactoryConfig(servlet, moduleConfig);
      // Set the module name in the config. This name will be used to compute
      // the name under which the factory is stored.
    factoryConfig.setFactoryName(moduleConfig.getPrefix());
      // Set RequestProcessor class
    initRequestProcessorClass(moduleConfig);

      // Set Tiles util implementation according to properties 'tilesUtilImplClassname'
      // and 'moduleAware'.
      // These properties are taken into account only once. A
      // side effect is that only the values set in the first initialized plugin
      // are effectively taken into account.
    if( !TilesUtil.isTilesUtilImplSet())
      { // TilesUtilImpl not set , do it
        // Check if user has specified a TilesUtil implementation classname or not.
        // If no implementation is specified, check if user has specified one
        // shared single factory for all module, or one factory for each module.
      if( getTilesUtilImplClassname() == null )
        { // No implementation specified, check if moduleAware is set
        if (isModuleAware())
          {   // Use appropriate TilesUtil implementation
          TilesUtil.setTilesUtil(new TilesUtilStrutsModulesImpl());
          }
         else
          { // Use appropriate TilesUtil implementation
          TilesUtil.setTilesUtil(new TilesUtilStrutsImpl());
          }
        }
       else
        { // A classname is specified for the tilesUtilImp, use it.
        try
          {
        TilesUtilStrutsImpl impl =
            (TilesUtilStrutsImpl) RequestUtils
                .applicationClass(getTilesUtilImplClassname())
                .newInstance();
        TilesUtil.setTilesUtil(impl);
          }
         catch( ClassCastException ex )