001/* 002 * Copyright 2002-2018 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.util.ClassUtils; 028import org.springframework.web.context.WebApplicationContext; 029 030/** 031 * Tiles {@link org.apache.tiles.preparer.PreparerFactory} implementation 032 * that expects preparer class names and builds preparer instances for those, 033 * creating them through the Spring ApplicationContext in order to apply 034 * Spring container callbacks and configured Spring BeanPostProcessors. 035 * 036 * @author Juergen Hoeller 037 * @since 3.2 038 * @see SpringBeanPreparerFactory 039 */ 040public class SimpleSpringPreparerFactory extends AbstractSpringPreparerFactory { 041 042 /** Cache of shared ViewPreparer instances: bean name -> bean instance. */ 043 private final Map<String, ViewPreparer> sharedPreparers = new ConcurrentHashMap<>(16); 044 045 046 @Override 047 protected ViewPreparer getPreparer(String name, WebApplicationContext context) throws TilesException { 048 // Quick check on the concurrent map first, with minimal locking. 049 ViewPreparer preparer = this.sharedPreparers.get(name); 050 if (preparer == null) { 051 synchronized (this.sharedPreparers) { 052 preparer = this.sharedPreparers.get(name); 053 if (preparer == null) { 054 try { 055 Class<?> beanClass = ClassUtils.forName(name, context.getClassLoader()); 056 if (!ViewPreparer.class.isAssignableFrom(beanClass)) { 057 throw new PreparerException( 058 "Invalid preparer class [" + name + "]: does not implement ViewPreparer interface"); 059 } 060 preparer = (ViewPreparer) context.getAutowireCapableBeanFactory().createBean(beanClass); 061 this.sharedPreparers.put(name, preparer); 062 } 063 catch (ClassNotFoundException ex) { 064 throw new NoSuchPreparerException("Preparer class [" + name + "] not found", ex); 065 } 066 } 067 } 068 } 069 return preparer; 070 } 071 072}