1 /*
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3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4  *
5  * This code is free software; you can redistribute it and/or modify it
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7  * published by the Free Software Foundation.  Oracle designates this
8  * particular file as subject to the "Classpath" exception as provided
9  * by Oracle in the LICENSE file that accompanied this code.
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11  * This code is distributed in the hope that it will be useful, but WITHOUT
12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14  * version 2 for more details (a copy is included in the LICENSE file that
15  * accompanied this code).
16  *
17  * You should have received a copy of the GNU General Public License version
18  * 2 along with this work; if not, write to the Free Software Foundation,
19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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24  */
25 
26 package java.io;
27 
28 /**
29  * Context during upcalls from object stream to class-defined
30  * readObject/writeObject methods.
31  * Holds object currently being deserialized and descriptor for current class.
32  *
33  * This context keeps track of the thread it was constructed on, and allows
34  * only a single call of defaultReadObject, readFields, defaultWriteObject
35  * or writeFields which must be invoked on the same thread before the class's
36  * readObject/writeObject method has returned.
37  * If not set to the current thread, the getObj method throws NotActiveException.
38  */
39 final class SerialCallbackContext {
40     private final Object obj;
41     private final ObjectStreamClass desc;
42     /**
43      * Thread this context is in use by.
44      * As this only works in one thread, we do not need to worry about thread-safety.
45      */
46     private Thread thread;
47 
SerialCallbackContext(Object obj, ObjectStreamClass desc)48     public SerialCallbackContext(Object obj, ObjectStreamClass desc) {
49         this.obj = obj;
50         this.desc = desc;
51         this.thread = Thread.currentThread();
52     }
53 
getObj()54     public Object getObj() throws NotActiveException {
55         checkAndSetUsed();
56         return obj;
57     }
58 
getDesc()59     public ObjectStreamClass getDesc() {
60         return desc;
61     }
62 
check()63     public void check() throws NotActiveException {
64         if (thread != null && thread != Thread.currentThread()) {
65             throw new NotActiveException(
66                 "expected thread: " + thread + ", but got: " + Thread.currentThread());
67         }
68     }
69 
checkAndSetUsed()70     private void checkAndSetUsed() throws NotActiveException {
71         if (thread != Thread.currentThread()) {
72              throw new NotActiveException(
73               "not in readObject invocation or fields already read");
74         }
75         thread = null;
76     }
77 
setUsed()78     public void setUsed() {
79         thread = null;
80     }
81 }
82