1 /*
   2  * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
   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
   6  * under the terms of the GNU General Public License version 2 only, as
   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.
  10  *
  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.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  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</code> represents a generic XPath exception.</p>
  37  *
  38  * @author  <a href="Norman.Walsh@Sun.com">Norman Walsh</a>
  39  * @author <a href="mailto:Jeff.Suttor@Sun.COM">Jeff Suttor</a>
  40  * @since 1.5
  41  */
  42 public class XPathException extends Exception {
  43 
  44     private static final ObjectStreamField[] serialPersistentFields = {
  45         new ObjectStreamField( "cause", Throwable.class )
  46     };
  47 
  48     /**
  49      * <p>Stream Unique Identifier.</p>
  50      */
  51     private static final long serialVersionUID = -1837080260374986980L;
  52 
  53     /**
  54      * <p>Constructs a new <code>XPathException</code>
  55      * with the specified detail <code>message</code>.</p>
  56      *
  57      * <p>The <code>cause</code> is not initialized.</p>
  58      *
  59      * <p>If <code>message</code> is <code>null</code>,
  60      * then a <code>NullPointerException</code> is thrown.</p>
  61      *
  62      * @param message The detail message.
  63      *
  64      * @throws NullPointerException When <code>message</code> is
  65      *   <code>null</code>.
  66      */
  67     public XPathException(String message) {
  68         super(message);
  69         if ( message == null ) {
  70             throw new NullPointerException ( "message can't be null");
  71         }
  72     }
  73 
  74     /**
  75      * <p>Constructs a new <code>XPathException</code>
  76      * with the specified <code>cause</code>.</p>
  77      *
  78      * <p>If <code>cause</code> is <code>null</code>,
  79      * then a <code>NullPointerException</code> is thrown.</p>
  80      *
  81      * @param cause The cause.
  82      *
  83      * @throws NullPointerException if <code>cause</code> is <code>null</code>.
  84      */
  85     public XPathException(Throwable cause) {
  86         super(cause);
  87         if ( cause == null ) {
  88             throw new NullPointerException ( "cause can't be null");
  89         }
  90     }
  91 
  92     /**
  93      * <p>Get the cause of this XPathException.</p>
  94      *
  95      * @return Cause of this XPathException.
  96      */
  97     public Throwable getCause() {
  98         return super.getCause();
  99     }
 100 
 101     /**
 102      * Writes "cause" field to the stream.
 103      * The cause is got from the parent class.
 104      *
 105      * @param out stream used for serialization.
 106      * @throws IOException thrown by <code>ObjectOutputStream</code>
 107      *
 108      */
 109     private void writeObject(ObjectOutputStream out)
 110             throws IOException
 111     {
 112         ObjectOutputStream.PutField fields = out.putFields();
 113         fields.put("cause", (Throwable) super.getCause());
 114         out.writeFields();
 115     }
 116 
 117     /**
 118      * Reads the "cause" field from the stream.
 119      * And initializes the "cause" if it wasn't
 120      * done before.
 121      *
 122      * @param in stream used for deserialization
 123      * @throws IOException thrown by <code>ObjectInputStream</code>
 124      * @throws ClassNotFoundException  thrown by <code>ObjectInputStream</code>
 125      */
 126     private void readObject(ObjectInputStream in)
 127             throws IOException, ClassNotFoundException
 128     {
 129         ObjectInputStream.GetField fields = in.readFields();
 130         Throwable scause = (Throwable) fields.get("cause", null);
 131 
 132         if (super.getCause() == null && scause != null) {
 133             try {
 134                 super.initCause(scause);
 135             } catch(IllegalStateException e) {
 136                 throw new InvalidClassException("Inconsistent state: two causes");
 137             }
 138         }
 139     }
 140 
 141     /**
 142      * <p>Print stack trace to specified <code>PrintStream</code>.</p>
 143      *
 144      * @param s Print stack trace to this <code>PrintStream</code>.
 145      */
 146     public void printStackTrace(java.io.PrintStream s) {
 147         if (getCause() != null) {
 148             getCause().printStackTrace(s);
 149           s.println("--------------- linked to ------------------");
 150         }
 151 
 152         super.printStackTrace(s);
 153     }
 154 
 155     /**
 156      * <p>Print stack trace to <code>System.err</code>.</p>
 157      */
 158     public void printStackTrace() {
 159         printStackTrace(System.err);
 160     }
 161 
 162     /**
 163      * <p>Print stack trace to specified <code>PrintWriter</code>.</p>
 164      *
 165      * @param s Print stack trace to this <code>PrintWriter</code>.
 166      */
 167     public void printStackTrace(PrintWriter s) {
 168 
 169         if (getCause() != null) {
 170             getCause().printStackTrace(s);
 171           s.println("--------------- linked to ------------------");
 172         }
 173 
 174         super.printStackTrace(s);
 175     }
 176 }