001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing,
013     * software distributed under the License is distributed on an
014     * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015     * KIND, either express or implied.  See the License for the
016     * specific language governing permissions and limitations
017     * under the License.
018     */
019    package org.apache.shiro.guice;
020    
021    import com.google.inject.Key;
022    import com.google.inject.OutOfScopeException;
023    import com.google.inject.Provider;
024    import com.google.inject.Scope;
025    import org.apache.shiro.session.Session;
026    import org.apache.shiro.subject.Subject;
027    import org.apache.shiro.util.ThreadContext;
028    
029    /**
030     * Guice scope for Shiro sessions.  Not bound by default.
031     */
032    public class ShiroSessionScope implements Scope {
033        public <T> Provider<T> scope(final Key<T> key, final Provider<T> unscoped) {
034            return new Provider<T>() {
035                public T get() {
036                    Subject subject = ThreadContext.getSubject();
037                    if (subject == null) {
038                        throw new OutOfScopeException("There is no Shiro Session currently in scope.");
039                    }
040                    Session session = subject.getSession();
041                    T scoped = castSessionAttribute(session);
042                    if (scoped == null) {
043                        scoped = unscoped.get();
044                    }
045                    return scoped;
046                }
047    
048                @SuppressWarnings({"unchecked"})
049                private T castSessionAttribute(Session session) {
050                    return (T) session.getAttribute(key);
051                }
052    
053                @Override
054                public String toString() {
055                    return unscoped.toString();
056                }
057            };
058        }
059    
060        @Override
061        public String toString() {
062            return "ShiroSessionScope";
063        }
064    }