/*

  * 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.shiro.guice;

 import com.google.inject.Key;

 import com.google.inject.OutOfScopeException;

 import com.google.inject.Provider;

 import com.google.inject.Scope;

 import org.apache.shiro.session.Session;

 import org.apache.shiro.subject.Subject;

 import org.apache.shiro.util.ThreadContext;

 /**

  * Guice scope for Shiro sessions.  Not bound by default.

  */

 public class ShiroSessionScope implements Scope {

     public <T> Provider<T> scope(final Key<T> key, final Provider<T> unscoped) {

         return new Provider<T>() {

             public T get() {

                 Subject subject = ThreadContext.getSubject();

                 if (subject == null) {

                     throw new OutOfScopeException("There is no Shiro Session currently in scope.");

                 }

                 Session session = subject.getSession();

                 T scoped = castSessionAttribute(session);

                 if (scoped == null) {

                     scoped = unscoped.get();

                 }

                 return scoped;

             }

             @SuppressWarnings({"unchecked"})

             private T castSessionAttribute(Session session) {

                 return (T) session.getAttribute(key);

             }

             @Override

             public String toString() {

                 return unscoped.toString();

             }

         };

     }

     @Override

     public String toString() {

         return "ShiroSessionScope";

     }

 }