/*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you 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.apache.myfaces.spi.impl;

 import java.lang.reflect.InvocationTargetException;

 import java.lang.reflect.Method;

 import java.lang.reflect.Modifier;

 import java.util.HashMap;

 import java.util.Map;

 import java.util.WeakHashMap;

 import javax.annotation.PostConstruct;

 import javax.annotation.PreDestroy;

 import javax.naming.NamingException;

 import org.apache.myfaces.shared.util.ClassUtils;

 import org.apache.myfaces.spi.InjectionProvider;

 import org.apache.myfaces.spi.InjectionProviderException;

 /**

  * See SRV.14.5 Servlet Specification Version 2.5 JSR 154

  * and Common Annotations for the Java Platform JSR 250

  */

 public class NoInjectionAnnotationInjectionProvider extends InjectionProvider

 {

      /**

      * Cache the Method instances per ClassLoader using the Class-Name.

      * NOTE that we do it this way, because the only other valid way in order to support a shared

      * classloader scenario would be to use a WeakHashMap<Class<?>, Method[]>, but this

      * creates a cyclic reference between the key and the value of the WeakHashMap which will

      * most certainly cause a memory leak! Furthermore we can manually cleanup the Map when

      * the webapp is undeployed just by removing the Map for the current ClassLoader. 

      */

     private volatile static WeakHashMap<ClassLoader, Map<Class,Method[]> > declaredMethodBeans = 

             new WeakHashMap<ClassLoader, Map<Class, Method[]>>();

     private static Map<Class,Method[]> getDeclaredMethodBeansMap()

     {

         ClassLoader cl = ClassUtils.getContextClassLoader();

         Map<Class,Method[]> metadata = (Map<Class,Method[]>)

                 declaredMethodBeans.get(cl);

         if (metadata == null)

         {

             // Ensure thread-safe put over _metadata, and only create one map

             // per classloader to hold metadata.

             synchronized (declaredMethodBeans)

             {

                 metadata = createDeclaredMethodBeansMap(cl, metadata);

             }

         }

         return metadata;

     }

     private static Map<Class,Method[]> createDeclaredMethodBeansMap(

             ClassLoader cl, Map<Class,Method[]> metadata)

     {

         metadata = (Map<Class,Method[]>) declaredMethodBeans.get(cl);

         if (metadata == null)

         {

             metadata = new HashMap<Class,Method[]>();

             declaredMethodBeans.put(cl, metadata);

         }

         return metadata;

     }

     @Override

     public Object inject(Object instance) throws InjectionProviderException

     {

         try

         {

             processAnnotations(instance);

         }

         catch (IllegalAccessException ex)

         {

             throw new InjectionProviderException(ex);

         }

         catch (InvocationTargetException ex)

         {

             throw new InjectionProviderException(ex);

         }

         catch (NamingException ex)

         {

             throw new InjectionProviderException(ex);

         }

         return null;

     }

     Method[] getDeclaredMethods(Class clazz)

     {

         Map<Class,Method[]> declaredMethodBeansMap = getDeclaredMethodBeansMap();

         Method[] methods = declaredMethodBeansMap.get(clazz);

         if (methods == null)

         {

             methods = clazz.getDeclaredMethods();

             synchronized(declaredMethodBeansMap)

             {

                 declaredMethodBeansMap.put(clazz, methods);

             }

         }

         return methods;

     }

     /**

      * Call postConstruct method on the specified instance.

      */

     @Override

     public void postConstruct(Object instance, Object creationMetaData) throws InjectionProviderException

     {

         // TODO the servlet spec is not clear about searching in superclass??

         Class clazz = instance.getClass();

         Method[] methods = getDeclaredMethods(clazz);

         if (methods == null)

         {

             methods = clazz.getDeclaredMethods();

             Map<Class,Method[]> declaredMethodBeansMap = getDeclaredMethodBeansMap();

             synchronized(declaredMethodBeansMap)

             {

                 declaredMethodBeansMap.put(clazz, methods);

             }

         }

         Method postConstruct = null;

         for (int i = 0; i < methods.length; i++)

         {

             Method method = methods[i];

             if (method.isAnnotationPresent(PostConstruct.class))

             {

                 // a method that does not take any arguments

                 // the method must not be static

                 // must not throw any checked expections

                 // the return value must be void

                 // the method may be public, protected, package private or private

                 if ((postConstruct != null)

                         || (method.getParameterTypes().length != 0)

                         || (Modifier.isStatic(method.getModifiers()))

                         || (method.getExceptionTypes().length > 0)

                         || (!method.getReturnType().getName().equals("void")))

                 {

                     throw new IllegalArgumentException("Invalid PostConstruct annotation");

                 }

                 postConstruct = method;

             }

         }

         try

         {

             invokeAnnotatedMethod(postConstruct, instance);

         }

         catch (IllegalAccessException ex)

         {

             throw new InjectionProviderException(ex);

         }

         catch (InvocationTargetException ex)

         {

             throw new InjectionProviderException(ex);

         }

     }

     @Override

     public void preDestroy(Object instance, Object creationMetaData) throws InjectionProviderException

     {

         // TODO the servlet spec is not clear about searching in superclass??

         // May be only check non private fields and methods

         Class clazz = instance.getClass();

         Method[] methods = getDeclaredMethods(clazz);

         Method preDestroy = null;

         for (int i = 0; i < methods.length; i++)

         {

             Method method = methods[i];

             if (method.isAnnotationPresent(PreDestroy.class))

             {

                 // must not throw any checked expections

                 // the method must not be static

                 // must not throw any checked expections

                 // the return value must be void

                 // the method may be public, protected, package private or private

                 if ((preDestroy != null)

                         || (method.getParameterTypes().length != 0)

                         || (Modifier.isStatic(method.getModifiers()))

                         || (method.getExceptionTypes().length > 0)

                         || (!method.getReturnType().getName().equals("void")))

                 {

                     throw new IllegalArgumentException("Invalid PreDestroy annotation");

                 }

                 preDestroy = method;

             }

         }

         try

         {

             invokeAnnotatedMethod(preDestroy, instance);

         }

         catch (IllegalAccessException ex)

         {

             throw new InjectionProviderException(ex);

         }

         catch (InvocationTargetException ex)

         {

             throw new InjectionProviderException(ex);

         }

     }

     private void invokeAnnotatedMethod(Method method, Object instance)

                 throws IllegalAccessException, InvocationTargetException

     {

         // At the end the annotated

         // method is invoked

         if (method != null)

         {

             boolean accessibility = method.isAccessible();

             method.setAccessible(true);

             method.invoke(instance);

             method.setAccessible(accessibility);

         }

     }

      /**

      * Inject resources in specified instance.

      */

     protected void processAnnotations(Object instance)

             throws IllegalAccessException, InvocationTargetException, NamingException

     {

     }

 }