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 * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

package javax.xml.xpath;

import java.io.PrintWriter;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.ObjectStreamField;
import java.io.InvalidClassException;

/**
 * <code>XPathException</code> represents a generic XPath exception.</p>
 *
 * @author <a href="Norman.Walsh@Sun.com">Norman Walsh</a>
 * @author <a href="mailto:Jeff.Suttor@Sun.COM">Jeff Suttor</a>
 * @since 1.5
 */
public class XPathException extends Exception {

 private static final ObjectStreamField[] serialPersistentFields = {
 new ObjectStreamField( "cause", Throwable.class )
 };

 /**
 * <p>Stream Unique Identifier.</p>
 */
 private static final long serialVersionUID = -1837080260374986980L;

 /**
 * <p>Constructs a new <code>XPathException</code>
 * with the specified detail <code>message</code>.</p>
 *
 * <p>The <code>cause</code> is not initialized.</p>
 *
 * <p>If <code>message</code> is <code>null</code>,
 * then a <code>NullPointerException</code> is thrown.</p>
 *
 * @param message The detail message.
 *
 * @throws NullPointerException When <code>message</code> is
 * <code>null</code>.
 */
 public XPathException(String message) {
 super(message);
 if ( message == null ) {
 throw new NullPointerException ( "message can't be null");
 }
 }

 /**
 * <p>Constructs a new <code>XPathException</code>
 * with the specified <code>cause</code>.</p>
 *
 * <p>If <code>cause</code> is <code>null</code>,
 * then a <code>NullPointerException</code> is thrown.</p>
 *
 * @param cause The cause.
 *
 * @throws NullPointerException if <code>cause</code> is <code>null</code>.
 */
 public XPathException(Throwable cause) {
 super(cause);
 if ( cause == null ) {
 throw new NullPointerException ( "cause can't be null");
 }
 }

 /**
 * <p>Get the cause of this XPathException.</p>
 *
 * @return Cause of this XPathException.
 */
 public Throwable getCause() {
 return super.getCause();
 }

 /**
 * Writes "cause" field to the stream.
 * The cause is got from the parent class.
 *
 * @param out stream used for serialization.
 * @throws IOException thrown by <code>ObjectOutputStream</code>
 *
 */
 private void writeObject(ObjectOutputStream out)
 throws IOException
 {
 ObjectOutputStream.PutField fields = out.putFields();
 fields.put("cause", (Throwable) super.getCause());
 out.writeFields();
 }

 /**
 * Reads the "cause" field from the stream.
 * And initializes the "cause" if it wasn't
 * done before.
 *
 * @param in stream used for deserialization
 * @throws IOException thrown by <code>ObjectInputStream</code>
 * @throws ClassNotFoundException thrown by <code>ObjectInputStream</code>
 */
 private void readObject(ObjectInputStream in)
 throws IOException, ClassNotFoundException
 {
 ObjectInputStream.GetField fields = in.readFields();
 Throwable scause = (Throwable) fields.get("cause", null);

 if (super.getCause() == null && scause != null) {
 try {
 super.initCause(scause);
 } catch(IllegalStateException e) {
 throw new InvalidClassException("Inconsistent state: two causes");
 }
 }
 }

 /**
 * <p>Print stack trace to specified <code>PrintStream</code>.</p>
 *
 * @param s Print stack trace to this <code>PrintStream</code>.
 */
 public void printStackTrace(java.io.PrintStream s) {
 if (getCause() != null) {
 getCause().printStackTrace(s);
 s.println("--------------- linked to ------------------");
 }

 super.printStackTrace(s);
 }

 /**
 * <p>Print stack trace to <code>System.err</code>.</p>
 */
 public void printStackTrace() {
 printStackTrace(System.err);
 }

 /**
 * <p>Print stack trace to specified <code>PrintWriter</code>.</p>
 *
 * @param s Print stack trace to this <code>PrintWriter</code>.
 */
 public void printStackTrace(PrintWriter s) {

 if (getCause() != null) {
 getCause().printStackTrace(s);
 s.println("--------------- linked to ------------------");
 }

 super.printStackTrace(s);
 }
}