/*
* 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.beans.factory.support;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.security.PrivilegedExceptionAction;
import org.springframework.beans.BeanInstantiationException;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.BeanDefinitionStoreException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.util.ReflectionUtils;
import org.springframework.util.StringUtils;
/**
* Simple object instantiation strategy for use in a BeanFactory.
*
* <p>Does not support Method Injection, although it provides hooks for subclasses
* to override to add Method Injection support, for example by overriding methods.
*
* @author Rod Johnson
* @author Juergen Hoeller
* @since 1.1
*/
public class SimpleInstantiationStrategy implements InstantiationStrategy {
private static final ThreadLocal<Method> currentlyInvokedFactoryMethod = new ThreadLocal<Method>();
/**
* Return the factory method currently being invoked or {@code null} if none.
* <p>Allows factory method implementations to determine whether the current
* caller is the container itself as opposed to user code.
*/
public static Method getCurrentlyInvokedFactoryMethod() {
return currentlyInvokedFactoryMethod.get();
}
public Object instantiate(RootBeanDefinition beanDefinition, String beanName, BeanFactory owner) {
// Don't override the class with CGLIB if no overrides.
if (beanDefinition.getMethodOverrides().isEmpty()) {
Constructor<?> constructorToUse;
synchronized (beanDefinition.constructorArgumentLock) {
constructorToUse = (Constructor<?>) beanDefinition.resolvedConstructorOrFactoryMethod;
if (constructorToUse == null) {
final Class clazz = beanDefinition.getBeanClass();
if (clazz.isInterface()) {
throw new BeanInstantiationException(clazz, "Specified class is an interface");
}
try {
if (System.getSecurityManager() != null) {
constructorToUse = AccessController.doPrivileged(new PrivilegedExceptionAction<Constructor>() {
public Constructor run() throws Exception {
return clazz.getDeclaredConstructor((Class[]) null);
}
});
}
else {
constructorToUse = clazz.getDeclaredConstructor((Class[]) null);
}
beanDefinition.resolvedConstructorOrFactoryMethod = constructorToUse;
}
catch (Exception ex) {
throw new BeanInstantiationException(clazz, "No default constructor found", ex);
}
}
}
return BeanUtils.instantiateClass(constructorToUse);
}
else {
// Must generate CGLIB subclass.
return instantiateWithMethodInjection(beanDefinition, beanName, owner);
}
}
/**
* Subclasses can override this method, which is implemented to throw
* UnsupportedOperationException, if they can instantiate an object with
* the Method Injection specified in the given RootBeanDefinition.
* Instantiation should use a no-arg constructor.
*/
protected Object instantiateWithMethodInjection(
RootBeanDefinition beanDefinition, String beanName, BeanFactory owner) {
throw new UnsupportedOperationException(
"Method Injection not supported in SimpleInstantiationStrategy");
}
public Object instantiate(RootBeanDefinition beanDefinition, String beanName, BeanFactory owner,
final Constructor<?> ctor, Object[] args) {
if (beanDefinition.getMethodOverrides().isEmpty()) {
if (System.getSecurityManager() != null) {
// use own privileged to change accessibility (when security is on)
AccessController.doPrivileged(new PrivilegedAction<Object>() {
public Object run() {
ReflectionUtils.makeAccessible(ctor);
return null;
}
});
}
return BeanUtils.instantiateClass(ctor, args);
}
else {
return instantiateWithMethodInjection(beanDefinition, beanName, owner, ctor, args);
}
}
/**
* Subclasses can override this method, which is implemented to throw
* UnsupportedOperationException, if they can instantiate an object with
* the Method Injection specified in the given RootBeanDefinition.
* Instantiation should use the given constructor and parameters.
*/
protected Object instantiateWithMethodInjection(RootBeanDefinition beanDefinition,
String beanName, BeanFactory owner, Constructor ctor, Object[] args) {
throw new UnsupportedOperationException(
"Method Injection not supported in SimpleInstantiationStrategy");
}
public Object instantiate(RootBeanDefinition beanDefinition, String beanName, BeanFactory owner,
Object factoryBean, final Method factoryMethod, Object[] args) {
try {
if (System.getSecurityManager() != null) {
AccessController.doPrivileged(new PrivilegedAction<Object>() {
public Object run() {
ReflectionUtils.makeAccessible(factoryMethod);
return null;
}
});
}
else {
ReflectionUtils.makeAccessible(factoryMethod);
}
Method priorInvokedFactoryMethod = currentlyInvokedFactoryMethod.get();
try {
currentlyInvokedFactoryMethod.set(factoryMethod);
return factoryMethod.invoke(factoryBean, args);
}
finally {
if (priorInvokedFactoryMethod != null) {
currentlyInvokedFactoryMethod.set(priorInvokedFactoryMethod);
}
else {
currentlyInvokedFactoryMethod.remove();
}
}
}
catch (IllegalArgumentException ex) {
throw new BeanDefinitionStoreException(
"Illegal arguments to factory method [" + factoryMethod + "]; " +
"args: " + StringUtils.arrayToCommaDelimitedString(args));
}
catch (IllegalAccessException ex) {
throw new BeanDefinitionStoreException(
"Cannot access factory method [" + factoryMethod + "]; is it public?");
}
catch (InvocationTargetException ex) {
throw new BeanDefinitionStoreException(
"Factory method [" + factoryMethod + "] threw exception", ex.getTargetException());
}
}
}