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Java > Open Source Codes > org > apache > ojb > broker > metadata > fieldaccess > PersistentFieldPrivilegedImpl


1 package org.apache.ojb.broker.metadata.fieldaccess;
2
3 /* Copyright 2003-2005 The Apache Software Foundation
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  *
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
18 import java.io.Serializable JavaDoc;
19 import java.lang.reflect.Field JavaDoc;
20 import java.security.AccessController JavaDoc;
21 import java.security.PrivilegedAction JavaDoc;
22
23 /**
24  * A {@link PersistentField} implementation using
25  * reflection to access but does cooperate with
26  * AccessController and do not suppress the java
27  * language access check.
28  *
29  * @version $Id: PersistentFieldPrivilegedImpl.java,v 1.11.2.2 2005/12/21 22:26:41 tomdz Exp $
30  * @see PersistentFieldDirectImpl
31  */
32 public class PersistentFieldPrivilegedImpl extends PersistentFieldDirectImpl
33 {
34     private static final long serialVersionUID = -6110158693763128846L;
35
36     private SetAccessibleAction setAccessibleAction = new SetAccessibleAction();
37     private UnsetAccessibleAction unsetAccessibleAction = new UnsetAccessibleAction();
38     private static final int ACCESSIBLE_STATE_UNKOWN = 0;
39     private static final int ACCESSIBLE_STATE_FALSE = 1;
40     private static final int ACCESSIBLE_STATE_SET_TRUE = 2;
41
42     public PersistentFieldPrivilegedImpl()
43     {
44     }
45
46     public PersistentFieldPrivilegedImpl(Class JavaDoc type, String JavaDoc fieldname)
47     {
48         super(type, fieldname);
49     }
50
51     protected Object JavaDoc getValueFrom(Field JavaDoc field, Object JavaDoc target)
52     {
53         int accessibleState = ACCESSIBLE_STATE_UNKOWN;
54         Object JavaDoc result = null;
55         if (!field.isAccessible()) accessibleState = ACCESSIBLE_STATE_FALSE;
56         if (accessibleState == ACCESSIBLE_STATE_FALSE)
57         {
58             accessibleState = ACCESSIBLE_STATE_SET_TRUE;
59             setAccessibleAction.current = field;
60             AccessController.doPrivileged(setAccessibleAction);
61         }
62         try
63         {
64             result = super.getValueFrom(field, target);
65         }
66         finally
67         {
68             if (accessibleState == ACCESSIBLE_STATE_SET_TRUE)
69             {
70                 unsetAccessibleAction.current = field;
71                 AccessController.doPrivileged(unsetAccessibleAction);
72             }
73         }
74         return result;
75     }
76
77     protected void setValueFor(Field JavaDoc field, Object JavaDoc target, Object JavaDoc value)
78     {
79         int accessibleState = ACCESSIBLE_STATE_UNKOWN;
80         if (!field.isAccessible()) accessibleState = ACCESSIBLE_STATE_FALSE;
81         if (accessibleState == ACCESSIBLE_STATE_FALSE)
82         {
83             accessibleState = ACCESSIBLE_STATE_SET_TRUE;
84             setAccessibleAction.current = field;
85             AccessController.doPrivileged(setAccessibleAction);
86         }
87         try
88         {
89             super.setValueFor(field, target, value);
90         }
91         finally
92         {
93             if (accessibleState == ACCESSIBLE_STATE_SET_TRUE)
94             {
95                 unsetAccessibleAction.current = field;
96                 AccessController.doPrivileged(unsetAccessibleAction);
97             }
98         }
99     }
100
101     /**
102      * This implementation returns always 'false'.
103      */
104     public boolean makeAccessible()
105     {
106         return false;
107     }
108
109     /**
110      * Always returns 'false'.
111      *
112      * @see PersistentField#usesAccessorsAndMutators
113      */
114     public boolean usesAccessorsAndMutators()
115     {
116         return false;
117     }
118
119     //************************************************************
120 // inner class
121 //************************************************************
122 private static class SetAccessibleAction implements PrivilegedAction JavaDoc, Serializable JavaDoc
123     {
124         static final long serialVersionUID = 8152025069698028050L;
125         transient Field JavaDoc current;
126
127         public Object JavaDoc run()
128         {
129             current.setAccessible(true);
130             return null;
131         }
132     }
133
134     private static class UnsetAccessibleAction implements PrivilegedAction JavaDoc, Serializable JavaDoc
135     {
136         static final long serialVersionUID = -2284913657454430305L;
137         transient Field JavaDoc current;
138
139         public Object JavaDoc run()
140         {
141             current.setAccessible(false);
142             return null;
143         }
144     }
145 }
146
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