/*

  * 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.cdi.util;

 import javax.enterprise.context.ContextNotActiveException;

 import javax.enterprise.context.spi.Context;

 import javax.enterprise.context.spi.Contextual;

 import javax.enterprise.context.spi.CreationalContext;

 import javax.enterprise.inject.spi.BeanManager;

 import javax.enterprise.inject.spi.PassivationCapable;

 import java.util.Map;

 /**

  * A skeleton containing the most important parts of a custom CDI Context.

  * An implementing Context needs to implement the missing methods from the

  * {@link Context} interface and {@link #getContextualStorage(boolean)}.

  * 

  * NOTE: Taken from Apache DeltaSpike

  */

 public abstract class AbstractContext implements Context

 {

     /**

      * Whether the Context is for a passivating scope.

      */

     private final boolean passivatingScope;

     protected AbstractContext(BeanManager beanManager)

     {

         passivatingScope = beanManager.isPassivatingScope(getScope());

     }

     /**

      * An implementation has to return the underlying storage which

      * contains the items held in the Context.

      * @param createIfNotExist whether a ContextualStorage shall get created if it doesn't yet exist.

      * @return the underlying storage

      */

     protected abstract ContextualStorage getContextualStorage(boolean createIfNotExist);

     /**

      * @return whether the served scope is a passivating scope

      */

     public boolean isPassivatingScope()

     {

         return passivatingScope;

     }

     @Override

     public <T> T get(Contextual<T> bean)

     {

         checkActive();

         ContextualStorage storage = getContextualStorage(false);

         if (storage == null)

         {

             return null;

         }

         Map<Object, ContextualInstanceInfo<?>> contextMap = storage.getStorage();

         ContextualInstanceInfo<?> contextualInstanceInfo = contextMap.get(storage.getBeanKey(bean));

         if (contextualInstanceInfo == null)

         {

             return null;

         }

         return (T) contextualInstanceInfo.getContextualInstance();

     }

     @Override

     public <T> T get(Contextual<T> bean, CreationalContext<T> creationalContext)

     {

         checkActive();

         if (passivatingScope)

         {

             if (!(bean instanceof PassivationCapable))

             {

                 throw new IllegalStateException(bean.toString() +

                         " doesn't implement " + PassivationCapable.class.getName());

             }

         }

         ContextualStorage storage = getContextualStorage(true);

         Map<Object, ContextualInstanceInfo<?>> contextMap = storage.getStorage();

         ContextualInstanceInfo<?> contextualInstanceInfo = contextMap.get(storage.getBeanKey(bean));

         if (contextualInstanceInfo != null)

         {

             @SuppressWarnings("unchecked")

             final T instance =  (T) contextualInstanceInfo.getContextualInstance();

             if (instance != null)

             {

                 return instance;

             }

         }

         return storage.createContextualInstance(bean, creationalContext);

     }

     /**

      * Destroy the Contextual Instance of the given Bean.

      * @param bean dictates which bean shall get cleaned up

      * @return <code>true</code> if the bean was destroyed, <code>false</code> if there was no such bean.

      */

     public boolean destroy(Contextual bean)

     {

         ContextualStorage storage = getContextualStorage(false);

         if (storage == null)

         {

             return false;

         }

         ContextualInstanceInfo<?> contextualInstanceInfo = storage.getStorage().get(storage.getBeanKey(bean));

         if (contextualInstanceInfo == null)

         {

             return false;

         }

         bean.destroy(contextualInstanceInfo.getContextualInstance(), contextualInstanceInfo.getCreationalContext());

         return true;

     }

     /**

      * destroys all the Contextual Instances in the Storage returned by

      * {@link #getContextualStorage(boolean)}.

      */

     public void destroyAllActive()

     {

         ContextualStorage storage = getContextualStorage(false);

         if (storage == null)

         {

             return;

         }

         destroyAllActive(storage);

     }

     /**

      * Destroys all the Contextual Instances in the specified ContextualStorage.

      * This is a static method to allow various holder objects to cleanup

      * properly in @PreDestroy.

      */

     public static void destroyAllActive(ContextualStorage storage)

     {

         Map<Object, ContextualInstanceInfo<?>> contextMap = storage.getStorage();

         for (Map.Entry<Object, ContextualInstanceInfo<?>> entry : contextMap.entrySet())

         {

             Contextual bean = storage.getBean(entry.getKey());

             ContextualInstanceInfo<?> contextualInstanceInfo = entry.getValue();

             bean.destroy(contextualInstanceInfo.getContextualInstance(), contextualInstanceInfo.getCreationalContext());

         }

     }

     /**

      * Make sure that the Context is really active.

      * @throws ContextNotActiveException if there is no active

      *         Context for the current Thread.

      */

     protected void checkActive()

     {

         if (!isActive())

         {

             throw new ContextNotActiveException("CDI context with scope annotation @"

                 + getScope().getName() + " is not active with respect to the current thread");

         }

     }

 }