Session


1   /**
2    *  Licensed to the Apache Software Foundation (ASF) under one or more
3    *  contributor license agreements.  See the NOTICE file distributed with
4    *  this work for additional information regarding copyright ownership.
5    *  The ASF licenses this file to You under the Apache License, Version 2.0
6    *  (the "License"); you may not use this file except in compliance with
7    *  the License.  You may obtain a copy of the License at
8    *
9    *     http://www.apache.org/licenses/LICENSE-2.0
10   *
11   *  Unless required by applicable law or agreed to in writing, software
12   *  distributed under the License is distributed on an "AS IS" BASIS,
13   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   *  See the License for the specific language governing permissions and
15   *  limitations under the License.
16   */
17  package org.apache.geronimo.clustering;
18  
19  import java.util.Map  ;
20  
21  /**
22   * Represents a clustered session.
23   * <p>
24   * A Session is created by a SessionManager and is uniquely identified by its sessionId. More accurately, this 
25   * sessionId is unique within the set of SessionManagers from which this Session has been sourced. If two Sessions 
26   * have the same sessionId, then a client can be sure that they have been created from two distinct set of 
27   * SessionManagers.
28   * <p>
29   * A Session provides Map like contracts to manipulate state information. State information must be Serializable as
30   * it may be marshalled automatically by the underpinning local SessionManager. At any given point of time, a Session
31   * is uniquely "instantiated" once cluster wide. Also, cluster wide accesses to a given Session are 
32   * ensured to be serialized by the set of SessionManagers from which the Session has been sourced. The interposition
33   * of a ClusteredInvocation between a client and the Session this client would like to access enforces unique
34   * instantiation and access serialization cluster wide for a given Session.
35   *
36   * @version $Rev$ $Date$
37   */
38  public interface Session {
39      
40      /**
41       * Gets the sessionId.
42       * 
43       * @return sessionId.
44       */
45      String   getSessionId();
46  
47      /**
48       * Map like contract to manipulate state information.
49       */
50      Object   addState(String   key, Object   value);
51  
52      /**
53       * Map like contract to manipulate state information.
54       */
55      Object   getState(String   key);
56  
57      /**
58       * Map like contract to manipulate state information.
59       */
60      Object   removeState(String   key);
61      
62      /**
63       * Map like contract to manipulate state information.
64       * <p>
65       * The returned Map is mutable and is backed by the session.
66       */
67      Map   getState();
68      
69      /**
70       * Releases the session.
71       * <p>
72       * When a Session is released, it is released from the underlying set of SessionManagers. In other words, its
73       * sessionId is unknown and its state is permanently lost. After the release of a Session, the behavior of
74       * the other methods is undefined.
75       */
76      void release();
77      
78  }
79
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