/*
    * 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
     {
 
     }
 }