/*
* Copyright 2008 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.constretto.spring;
import org.constretto.ConstrettoConfiguration;
import org.constretto.annotation.Configuration;
import org.constretto.exception.ConstrettoException;
import org.constretto.internal.introspect.ArgumentDescription;
import org.constretto.internal.introspect.ArgumentDescriptionFactory;
import org.constretto.internal.introspect.Constructors;
import org.constretto.spring.annotation.Environment;
import org.constretto.spring.resolver.AssemblyContextResolver;
import org.springframework.beans.BeanInstantiationException;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.*;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
/**
* {@link BeanPostProcessor} implementation that autowires annotated fields annotated with the @Configuration or
* @Environment annotations.
* <p/>
* <p/>
* Fields are injected right after construction of a bean, before any config methods are invoked. Such a config field
* does not have to be public.
* <p/>
* <p/>
* If a @Configuration element have the required flag set, and no value could be assosiated with the given key a
* {@link BeanInstantiationException} is thrown invalidating the entire context.
*
* @author <a href="mailto:kaare.nilsen@gmail.com">Kaare Nilsen</a>
* @see Configuration
* @see org.constretto.spring.annotation.Environment
*/
public class ConfigurationAnnotationConfigurer extends InstantiationAwareBeanPostProcessorAdapter implements
BeanFactoryPostProcessor {
private ConstrettoConfiguration configuration;
private AssemblyContextResolver assemblyContextResolver;
private Map<Class<?>, Constructor<?>> configurableConstructorCache = Collections.synchronizedMap(new HashMap<Class<?>, Constructor<?>>());
private final static Object constructorCacheLockObject = new Object();
public ConfigurationAnnotationConfigurer(ConstrettoConfiguration configuration,
AssemblyContextResolver assemblyContextResolver) {
this.configuration = configuration;
this.assemblyContextResolver = assemblyContextResolver;
}
@Override
public Constructor<?>[] determineCandidateConstructors(final Class<?> beanClass, final String beanName) throws
BeansException {
final Constructor<?> constructor = configurableConstructorCache.get(beanClass);
if (constructor == null) {
return null;
} else {
return new Constructor<?>[]{constructor};
}
}
@Override
public boolean postProcessAfterInstantiation(Object bean, String beanName) throws BeansException {
injectConfiguration(bean);
injectEnvironment(bean);
return true;
}
public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
return bean;
}
private void injectEnvironment(final Object bean) {
try {
Field[] fields = bean.getClass().getDeclaredFields();
for (Field field : fields) {
if (field.isAnnotationPresent(Environment.class)) {
field.setAccessible(true);
field.set(bean, assemblyContextResolver.getAssemblyContext());
}
}
} catch (IllegalAccessException e) {
throw new BeanInstantiationException(bean.getClass(), "Could not inject Environment on spring bean");
}
}
private void injectConfiguration(final Object bean) {
configuration.on(bean);
}
@Override
public void postProcessBeanFactory(final ConfigurableListableBeanFactory beanFactory) throws BeansException {
for (String beanName : beanFactory.getBeanDefinitionNames()) {
final BeanDefinition beanDefinition = beanFactory.getBeanDefinition(beanName);
final Class<?> beanType = beanFactory.getType(beanName);
if (!configurableConstructorCache.containsKey(beanType)) {
configurableConstructorCache.put(beanType, resolveConfigurableConstructor(beanType));
}
final Constructor<?> resolvedConstructor = configurableConstructorCache.get(beanType);
if (resolvedConstructor != null) {
final ConstructorArgumentValues constructorArgumentValues = beanDefinition.getConstructorArgumentValues();
final ArgumentDescription[] argumentDescriptions = ArgumentDescriptionFactory.create(resolvedConstructor).resolveParameters();
for (int i = 0; i < argumentDescriptions.length; i++) {
ArgumentDescription argumentDescription = argumentDescriptions[i];
if (!constructorArgumentValues.hasIndexedArgumentValue(i)) {
final String keyName = argumentDescription.constrettoConfigurationKeyCandidate();
if (configuration.hasValue(keyName)) {
constructorArgumentValues.addIndexedArgumentValue(i,
configuration.evaluateTo(
argumentDescription.getType(),
keyName));
}
}
}
}
}
}
private Constructor<?> resolveConfigurableConstructor(Class<?> beanClass) {
final Constructor[] constructorsWithConfigureAnnotation = Constructors.findConstructorsWithConfigureAnnotation(
beanClass);
if (constructorsWithConfigureAnnotation == null) {
return null;
} else {
if (constructorsWithConfigureAnnotation.length > 1) {
throw new ConstrettoException("You should only have one constructor annotated with @Configure");
}
return constructorsWithConfigureAnnotation[0];
}
}
}