/*
* Copyright 2002-2012 the original author or authors.
*
* Licensed 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.springframework.web.servlet.view.tiles2;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import org.apache.tiles.TilesException;
import org.apache.tiles.preparer.NoSuchPreparerException;
import org.apache.tiles.preparer.PreparerException;
import org.apache.tiles.preparer.ViewPreparer;
import org.springframework.web.context.WebApplicationContext;
/**
* Tiles2 {@link org.apache.tiles.preparer.PreparerFactory} implementation
* that expects preparer class names and builds preparer instances for those,
* creating them through the Spring ApplicationContext in order to apply
* Spring container callbacks and configured Spring BeanPostProcessors.
*
* @author Juergen Hoeller
* @since 2.5
* @see SpringBeanPreparerFactory
*/
public class SimpleSpringPreparerFactory extends AbstractSpringPreparerFactory {
/** Cache of shared ViewPreparer instances: bean name -> bean instance */
private final Map<String, ViewPreparer> sharedPreparers = new ConcurrentHashMap<String, ViewPreparer>(16);
@Override
protected ViewPreparer getPreparer(String name, WebApplicationContext context) throws TilesException {
// Quick check on the concurrent map first, with minimal locking.
ViewPreparer preparer = this.sharedPreparers.get(name);
if (preparer == null) {
synchronized (this.sharedPreparers) {
preparer = this.sharedPreparers.get(name);
if (preparer == null) {
try {
Class<?> beanClass = context.getClassLoader().loadClass(name);
if (!ViewPreparer.class.isAssignableFrom(beanClass)) {
throw new PreparerException(
"Invalid preparer class [" + name + "]: does not implement ViewPreparer interface");
}
preparer = (ViewPreparer) context.getAutowireCapableBeanFactory().createBean(beanClass);
this.sharedPreparers.put(name, preparer);
}
catch (ClassNotFoundException ex) {
throw new NoSuchPreparerException("Preparer class [" + name + "] not found", ex);
}
}
}
}
return preparer;
}
}