/*
* $Id: TilesUtilImpl.java 529384 2007-04-16 20:19:17Z bayard $
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.struts.tiles;
import java.io.IOException;
import java.io.Serializable;
import java.lang.reflect.Method;
import java.lang.reflect.InvocationTargetException;
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 static final 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";
/**
* JSP 2.0 include method to use which supports configurable flushing.
*/
private static Method include = null;
/**
* Initialize the include variable with the
* JSP 2.0 method if available.
*/
static {
try {
// get version of include method with flush argument
Class[] args = new Class[]{String.class, boolean.class};
include = PageContext.class.getMethod("include", args);
} catch (NoSuchMethodException e) {
log.debug("Could not find JSP 2.0 include method. Using old one that doesn't support " +
"configurable flushing.", e);
}
}
/**
* 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 pageContext Current page context.
* @param flush If the writer should be flushed before the include
*/
public void doInclude(String uri, PageContext pageContext, boolean flush)
throws IOException, ServletException {
try {
// perform include with new JSP 2.0 method that supports flushing
if (include != null) {
include.invoke(pageContext, new Object[]{uri, Boolean.valueOf(flush)});
return;
}
} catch (IllegalAccessException e) {
log.debug("Could not find JSP 2.0 include method. Using old one.", e);
} catch (InvocationTargetException e) {
if (e.getCause() instanceof ServletException){
throw ((ServletException)e.getCause());
} else if (e.getCause() instanceof IOException){
throw ((IOException)e.getCause());
} else {
throw new ServletException(e);
}
}
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 = RequestUtils.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);
}
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);
}
}