001/* 002 * Copyright 2002-2012 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.web.servlet.view.tiles3; 018 019import java.util.Map; 020import java.util.concurrent.ConcurrentHashMap; 021 022import org.apache.tiles.TilesException; 023import org.apache.tiles.preparer.PreparerException; 024import org.apache.tiles.preparer.ViewPreparer; 025import org.apache.tiles.preparer.factory.NoSuchPreparerException; 026 027import org.springframework.web.context.WebApplicationContext; 028 029/** 030 * Tiles {@link org.apache.tiles.preparer.PreparerFactory} implementation 031 * that expects preparer class names and builds preparer instances for those, 032 * creating them through the Spring ApplicationContext in order to apply 033 * Spring container callbacks and configured Spring BeanPostProcessors. 034 * 035 * @author Juergen Hoeller 036 * @since 3.2 037 * @see SpringBeanPreparerFactory 038 */ 039public class SimpleSpringPreparerFactory extends AbstractSpringPreparerFactory { 040 041 /** Cache of shared ViewPreparer instances: bean name -> bean instance */ 042 private final Map<String, ViewPreparer> sharedPreparers = new ConcurrentHashMap<String, ViewPreparer>(16); 043 044 045 @Override 046 protected ViewPreparer getPreparer(String name, WebApplicationContext context) throws TilesException { 047 // Quick check on the concurrent map first, with minimal locking. 048 ViewPreparer preparer = this.sharedPreparers.get(name); 049 if (preparer == null) { 050 synchronized (this.sharedPreparers) { 051 preparer = this.sharedPreparers.get(name); 052 if (preparer == null) { 053 try { 054 Class<?> beanClass = context.getClassLoader().loadClass(name); 055 if (!ViewPreparer.class.isAssignableFrom(beanClass)) { 056 throw new PreparerException( 057 "Invalid preparer class [" + name + "]: does not implement ViewPreparer interface"); 058 } 059 preparer = (ViewPreparer) context.getAutowireCapableBeanFactory().createBean(beanClass); 060 this.sharedPreparers.put(name, preparer); 061 } 062 catch (ClassNotFoundException ex) { 063 throw new NoSuchPreparerException("Preparer class [" + name + "] not found", ex); 064 } 065 } 066 } 067 } 068 return preparer; 069 } 070 071}