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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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8  * particular file as subject to the "Classpath" exception as provided
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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
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19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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24  */
25 
26 package javax.xml.xpath;
27 
28 import java.io.PrintWriter;
29 import java.io.IOException;
30 import java.io.ObjectInputStream;
31 import java.io.ObjectOutputStream;
32 import java.io.ObjectStreamField;
33 import java.io.InvalidClassException;
34 
35 /**
36  * {@code XPathException} represents a generic XPath exception.
37  *
38  * @author Norman Walsh
39  * @author Jeff Suttor
40  * @since 1.5
41  */
42 public class XPathException extends Exception {
43     /**
44      * Serializable fields.
45      */
46     private static final ObjectStreamField[] serialPersistentFields = {
47         new ObjectStreamField( "cause", Throwable.class )
48     };
49 
50     /**
51      * Stream Unique Identifier.
52      */
53     private static final long serialVersionUID = -1837080260374986980L;
54 
55     /**
56      * Constructs a new {@code XPathException}
57      * with the specified detail {@code message}.
58      *
59      * <p>The {@code cause} is not initialized.
60      *
61      * <p>If {@code message} is {@code null},
62      * then a {@code NullPointerException} is thrown.
63      *
64      * @param message The detail message.
65      *
66      * @throws NullPointerException When {@code message} is
67      *   {@code null}.
68      */
XPathException(String message)69     public XPathException(String message) {
70         super(message);
71         if ( message == null ) {
72             throw new NullPointerException ( "message can't be null");
73         }
74     }
75 
76     /**
77      * Constructs a new {@code XPathException}
78      * with the specified {@code cause}.
79      *
80      * <p>If {@code cause} is {@code null},
81      * then a {@code NullPointerException} is thrown.
82      *
83      * @param cause The cause.
84      *
85      * @throws NullPointerException if {@code cause} is {@code null}.
86      */
XPathException(Throwable cause)87     public XPathException(Throwable cause) {
88         super(cause);
89         if ( cause == null ) {
90             throw new NullPointerException ( "cause can't be null");
91         }
92     }
93 
94     /**
95      * Get the cause of this XPathException.
96      *
97      * @return Cause of this XPathException.
98      */
getCause()99     public Throwable getCause() {
100         return super.getCause();
101     }
102 
103     /**
104      * Writes "cause" field to the stream.
105      * The cause is got from the parent class.
106      *
107      * @param out stream used for serialization.
108      * @throws IOException thrown by {@code ObjectOutputStream}
109      *
110      */
writeObject(ObjectOutputStream out)111     private void writeObject(ObjectOutputStream out)
112             throws IOException
113     {
114         ObjectOutputStream.PutField fields = out.putFields();
115         fields.put("cause", super.getCause());
116         out.writeFields();
117     }
118 
119     /**
120      * Reads the "cause" field from the stream.
121      * And initializes the "cause" if it wasn't
122      * done before.
123      *
124      * @param in stream used for deserialization
125      * @throws IOException thrown by {@code ObjectInputStream}
126      * @throws ClassNotFoundException  thrown by {@code ObjectInputStream}
127      */
readObject(ObjectInputStream in)128     private void readObject(ObjectInputStream in)
129             throws IOException, ClassNotFoundException
130     {
131         ObjectInputStream.GetField fields = in.readFields();
132         Throwable scause = (Throwable) fields.get("cause", null);
133 
134         if (super.getCause() == null && scause != null) {
135             try {
136                 super.initCause(scause);
137             } catch(IllegalStateException e) {
138                 throw new InvalidClassException("Inconsistent state: two causes");
139             }
140         }
141     }
142 
143     /**
144      * Print stack trace to specified {@code PrintStream}.
145      *
146      * @param s Print stack trace to this {@code PrintStream}.
147      */
printStackTrace(java.io.PrintStream s)148     public void printStackTrace(java.io.PrintStream s) {
149         if (getCause() != null) {
150             getCause().printStackTrace(s);
151           s.println("--------------- linked to ------------------");
152         }
153 
154         super.printStackTrace(s);
155     }
156 
157     /**
158      * Print stack trace to {@code System.err}.
159      */
printStackTrace()160     public void printStackTrace() {
161         printStackTrace(System.err);
162     }
163 
164     /**
165      * Print stack trace to specified {@code PrintWriter}.
166      *
167      * @param s Print stack trace to this {@code PrintWriter}.
168      */
printStackTrace(PrintWriter s)169     public void printStackTrace(PrintWriter s) {
170 
171         if (getCause() != null) {
172             getCause().printStackTrace(s);
173           s.println("--------------- linked to ------------------");
174         }
175 
176         super.printStackTrace(s);
177     }
178 }
179