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Java > Open Source Codes > org > mortbay > j2ee > session > TypeCheckingInterceptor


1 // ========================================================================
2 // $Id: TypeCheckingInterceptor.java,v 1.4 2004/05/09 20:30:48 gregwilkins Exp $
3 // Copyright 2002-2004 Mort Bay Consulting Pty. Ltd.
4 // ------------------------------------------------------------------------
5 // Licensed under the Apache License, Version 2.0 (the "License");
6 // you may not use this file except in compliance with the License.
7 // You may obtain a copy of the License at
8 // http://www.apache.org/licenses/LICENSE-2.0
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 // ========================================================================
15
16 package org.mortbay.j2ee.session;
17
18 //----------------------------------------
19
20 import java.rmi.RemoteException JavaDoc;
21
22 import org.jfox.ioc.logger.Logger;
23
24 //----------------------------------------
25 // every time an attribute is added to the underlying HttpSession this
26 // interceptor ensures that the attribute type/value is one of :
27
28 // java.io.Serializable
29 // javax.ejb.EJBObject
30 // javax.ejb.EJBHome
31 // javax.transaction.UserTransaction - TODO - how/why ?
32 // javax.naming.Context - java:comp/env - we allow any Context
33
34 // TODO - How do we serialize Contexts and UserTransactions
35
36 public
37   class TypeCheckingInterceptor
38   extends StateInterceptor
39 {
40   protected static final Logger _log=Logger.getLogger(TypeCheckingInterceptor.class);
41
42   public Object JavaDoc
43     setAttribute(String JavaDoc name, Object JavaDoc value, boolean returnValue)
44     throws IllegalArgumentException JavaDoc, RemoteException JavaDoc
45   {
46     // SRV.7.7.2
47
48     Object JavaDoc tmp=value;
49
50     if (tmp!=null)
51     {
52       // The container may choose to support storage of other
53 // designated objects in the HttpSession, such as references
54 // to Enterprise JavaBean components and transactions.
55
56       if (tmp instanceof javax.ejb.EJBObject JavaDoc)
57     tmp=new SerializableEJBObject((javax.ejb.EJBObject JavaDoc)tmp);
58       else if (tmp instanceof javax.ejb.EJBHome JavaDoc)
59     tmp=new SerializableEJBHome((javax.ejb.EJBHome JavaDoc)tmp);
60       else if (tmp instanceof javax.naming.Context JavaDoc)
61     tmp=new SerializableContext((javax.naming.Context JavaDoc)tmp);
62       else if (tmp instanceof javax.transaction.UserTransaction JavaDoc)
63     tmp=new SerializableUserTransaction((javax.transaction.UserTransaction JavaDoc)tmp);
64     }
65
66     // The container must accept objects that implement the
67 // Serializable interface
68 if (tmp instanceof java.io.Serializable JavaDoc)
69     {
70       try
71       {
72     return super.setAttribute(name, tmp, returnValue);
73       }
74       catch (RemoteException JavaDoc e)
75       {
76     _log.error("could not set attribute", e);
77     return null;
78       }
79     }
80     else
81     {
82       // The servlet container may throw an IllegalArgumentException
83 // if an object is placed into the session that is not
84 // Serializable or for which specific support has not been made
85 // available.
86 throw new IllegalArgumentException JavaDoc("distributed attribute value must be Serializable,EJBObject,EJBHome,UserTransaction or Context: "+tmp);
87     }
88   }
89
90   public Object JavaDoc
91     getAttribute(String JavaDoc name)
92     throws IllegalArgumentException JavaDoc, RemoteException JavaDoc
93   {
94     Object JavaDoc tmp=super.getAttribute(name);
95
96     if (tmp!=null)
97     {
98       if (tmp instanceof org.mortbay.j2ee.session.SerializableEJBObject)
99     return ((SerializableEJBObject)tmp).toEJBObject();
100       else if (tmp instanceof org.mortbay.j2ee.session.SerializableEJBHome)
101     return ((SerializableEJBHome)tmp).toEJBHome();
102       else if (tmp instanceof org.mortbay.j2ee.session.SerializableContext)
103     return ((SerializableContext)tmp).toContext();
104       else if (tmp instanceof org.mortbay.j2ee.session.SerializableUserTransaction)
105     return ((SerializableUserTransaction)tmp).toUserTransaction();
106     }
107
108     return tmp;
109   }
110
111   // public Object clone() { return this; } // Stateless
112 }
113
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