/***
* Copyright (c) 2009 Caelum - www.caelum.com.br/opensource All rights reserved.
*
* 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 br.com.caelum.vraptor.core;
import java.lang.reflect.Constructor;
import net.vidageek.mirror.dsl.Mirror;
import net.vidageek.mirror.exception.MirrorException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import br.com.caelum.vraptor.InterceptionException;
import br.com.caelum.vraptor.interceptor.Interceptor;
import br.com.caelum.vraptor.ioc.Container;
import br.com.caelum.vraptor.resource.ResourceMethod;
class LazyInterceptorHandler implements InterceptorHandler {
private static final Logger logger = LoggerFactory.getLogger(LazyInterceptorHandler.class);
private final Container container;
private final Class<? extends Interceptor> type;
private Interceptor acceptor;
public LazyInterceptorHandler(Container container, Class<? extends Interceptor> type) {
this.container = container;
this.type = type;
}
public void execute(InterceptorStack stack, ResourceMethod method, Object resourceInstance)
throws InterceptionException {
boolean accepts;
try {
accepts = getAcceptor().accepts(method);
} catch (NullPointerException e) {
throw new InterceptionException("StaticInterceptors should not use constructor parameters inside the accepts method", e);
}
if (accepts) {
Interceptor interceptor = container.instanceFor(type);
if (interceptor == null) {
throw new InterceptionException("Unable to instantiate interceptor for " + type.getName()
+ ": the container returned null.");
}
logger.debug("Invoking interceptor {}", interceptor.getClass().getSimpleName());
interceptor.intercept(stack, method, resourceInstance);
} else {
stack.next(method, resourceInstance);
}
}
private Interceptor getAcceptor() {
if (acceptor == null) {
try {
Constructor<?> constructor = type.getDeclaredConstructors()[0];
int argsLength = constructor.getParameterTypes().length;
acceptor = type.cast(new Mirror().on(type).invoke().constructor(constructor).withArgs(new Object[argsLength]));
} catch (MirrorException e) {
if (e.getCause() instanceof NullPointerException) {
throw new InterceptionException("StaticInterceptors should not use constructor parameters inside the constructor", e);
} else {
throw new InterceptionException(e);
}
}
}
return acceptor;
}
}