/*
* Copyright (C) 2009 Google Inc.
*
* 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 com.google.inject.struts2;
import com.google.inject.AbstractModule;
import com.google.inject.Binder;
import com.google.inject.Injector;
import com.google.inject.internal.Annotations;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.ObjectFactory;
import com.opensymphony.xwork2.config.ConfigurationException;
import com.opensymphony.xwork2.config.entities.InterceptorConfig;
import com.opensymphony.xwork2.inject.Inject;
import com.opensymphony.xwork2.interceptor.Interceptor;
import java.lang.annotation.Annotation;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.logging.Logger;
/**
* Cleanup up version from Bob's GuiceObjectFactory. Now works properly with GS2 and fixes several
* bugs.
*
* @author dhanji@gmail.com
* @author benmccann.com
*/
public class Struts2Factory extends ObjectFactory {
private static final long serialVersionUID = 1L;
private static final Logger logger = Logger.getLogger(Struts2Factory.class.getName());
private static final String ERROR_NO_INJECTOR =
"Cannot find a Guice injector. Are you sure you registered a GuiceServletContextListener "
+ "that uses the Struts2GuicePluginModule in your application's web.xml?";
private static @com.google.inject.Inject Injector injector;
private final List<ProvidedInterceptor> interceptors = new ArrayList<ProvidedInterceptor>();
private volatile Injector strutsInjector;
@Override
public boolean isNoArgConstructorRequired() {
return false;
}
@Inject(value = "guice.module", required = false)
void setModule(String moduleClassName) {
throw new RuntimeException(
"The struts2 plugin no longer supports"
+ " specifying a module via the 'guice.module' property in XML."
+ " Please install your module via a GuiceServletContextListener instead.");
}
Set<Class<?>> boundClasses = new HashSet<Class<?>>();
@Override
public Class<?> getClassInstance(String name) throws ClassNotFoundException {
Class<?> clazz = super.getClassInstance(name);
synchronized (this) {
if (strutsInjector == null) {
// We can only bind each class once.
if (!boundClasses.contains(clazz)) {
try {
// Calling these methods now helps us detect ClassNotFoundErrors
// early.
clazz.getDeclaredFields();
clazz.getDeclaredMethods();
boundClasses.add(clazz);
} catch (Throwable t) {
// Struts should still work even though some classes aren't in the
// classpath. It appears we always get the exception here when
// this is the case.
return clazz;
}
}
}
}
return clazz;
}
@Override
@SuppressWarnings("unchecked")
public Object buildBean(Class clazz, Map<String, Object> extraContext) {
if (strutsInjector == null) {
synchronized (this) {
if (strutsInjector == null) {
createInjector();
}
}
}
return strutsInjector.getInstance(clazz);
}
private void createInjector() {
logger.info("Loading struts2 Guice support...");
// Something is wrong, since this should be there if GuiceServletContextListener
// was present.
if (injector == null) {
logger.severe(ERROR_NO_INJECTOR);
throw new RuntimeException(ERROR_NO_INJECTOR);
}
this.strutsInjector =
injector.createChildInjector(
new AbstractModule() {
@Override
protected void configure() {
// Tell the injector about all the action classes, etc., so it
// can validate them at startup.
for (Class<?> boundClass : boundClasses) {
// TODO: Set source from Struts XML.
bind(boundClass);
}
// Validate the interceptor class.
for (ProvidedInterceptor interceptor : interceptors) {
interceptor.validate(binder());
}
}
});
// Inject interceptors.
for (ProvidedInterceptor interceptor : interceptors) {
interceptor.inject();
}
logger.info("Injector created successfully.");
}
@Override
@SuppressWarnings("unchecked")
public Interceptor buildInterceptor(InterceptorConfig interceptorConfig, Map interceptorRefParams)
throws ConfigurationException {
// Ensure the interceptor class is present.
Class<? extends Interceptor> interceptorClass;
try {
interceptorClass =
(Class<? extends Interceptor>) getClassInstance(interceptorConfig.getClassName());
} catch (ClassNotFoundException e) {
throw new RuntimeException(e);
}
ProvidedInterceptor providedInterceptor =
new ProvidedInterceptor(interceptorConfig, interceptorRefParams, interceptorClass);
interceptors.add(providedInterceptor);
return providedInterceptor;
}
private Interceptor superBuildInterceptor(
InterceptorConfig interceptorConfig, Map<String, String> interceptorRefParams)
throws ConfigurationException {
return super.buildInterceptor(interceptorConfig, interceptorRefParams);
}
private class ProvidedInterceptor implements Interceptor {
private static final long serialVersionUID = 1L;
private final InterceptorConfig config;
private final Map<String, String> params;
private final Class<? extends Interceptor> interceptorClass;
private Interceptor delegate;
ProvidedInterceptor(
InterceptorConfig config,
Map<String, String> params,
Class<? extends Interceptor> interceptorClass) {
this.config = config;
this.params = params;
this.interceptorClass = interceptorClass;
}
void validate(Binder binder) {
// TODO: Set source from Struts XML.
if (hasScope(interceptorClass)) {
binder.addError(
"Scoping interceptors is not currently supported."
+ " Please remove the scope annotation from "
+ interceptorClass.getName()
+ ".");
}
// Make sure it implements Interceptor.
if (!Interceptor.class.isAssignableFrom(interceptorClass)) {
binder.addError(
interceptorClass.getName() + " must implement " + Interceptor.class.getName() + ".");
}
}
void inject() {
delegate = superBuildInterceptor(config, params);
}
@Override
public void destroy() {
if (null != delegate) {
delegate.destroy();
}
}
@Override
public void init() {
throw new AssertionError();
}
@Override
public String intercept(ActionInvocation invocation) throws Exception {
return delegate.intercept(invocation);
}
}
/** Returns true if the given class has a scope annotation. */
private static boolean hasScope(Class<? extends Interceptor> interceptorClass) {
for (Annotation annotation : interceptorClass.getAnnotations()) {
if (Annotations.isScopeAnnotation(annotation.annotationType())) {
return true;
}
}
return false;
}
}