/*

 * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

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);

    }

}