/*

 * 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 org.xml.sax;

import java.io.IOException;

import java.io.InvalidClassException;

import java.io.ObjectInputStream;

import java.io.ObjectOutputStream;

import java.io.ObjectStreamField;

/**

 * Encapsulate a general SAX error or warning.

 *

 * <p>This class can contain basic error or warning information from

 * either the XML parser or the application: a parser writer or

 * application writer can subclass it to provide additional

 * functionality.  SAX handlers may throw this exception or

 * any exception subclassed from it.</p>

 *

 * <p>If the application needs to pass through other types of

 * exceptions, it must wrap those exceptions in a SAXException

 * or an exception derived from a SAXException.</p>

 *

 * <p>If the parser or application needs to include information about a

 * specific location in an XML document, it should use the

 * {@link org.xml.sax.SAXParseException SAXParseException} subclass.</p>

 *

 * @since 1.4, SAX 1.0

 * @author David Megginson

 * @version 2.0.1 (sax2r2)

 * @see org.xml.sax.SAXParseException

 */

public class SAXException extends Exception {

    /**

     * Create a new SAXException.

     */

    public SAXException ()

    {

        super();

    }

    /**

     * Create a new SAXException.

     *

     * @param message The error or warning message.

     */

    public SAXException (String message) {

        super(message);

    }

    /**

     * Create a new SAXException wrapping an existing exception.

     *

     * <p>The existing exception will be embedded in the new

     * one, and its message will become the default message for

     * the SAXException.</p>

     *

     * @param e The exception to be wrapped in a SAXException.

     */

    public SAXException (Exception e)

    {

        super(e);

    }

    /**

     * Create a new SAXException from an existing exception.

     *

     * <p>The existing exception will be embedded in the new

     * one, but the new exception will have its own message.</p>

     *

     * @param message The detail message.

     * @param e The exception to be wrapped in a SAXException.

     */

    public SAXException (String message, Exception e)

    {

        super(message, e);

    }

    /**

     * Return a detail message for this exception.

     *

     * <p>If there is an embedded exception, and if the SAXException

     * has no detail message of its own, this method will return

     * the detail message from the embedded exception.</p>

     *

     * @return The error or warning message.

     */

    public String getMessage ()

    {

        String message = super.getMessage();

        Throwable cause = super.getCause();

        if (message == null && cause != null) {

            return cause.getMessage();

        } else {

            return message;

        }

    }

    /**

     * Return the embedded exception, if any.

     *

     * @return The embedded exception, or null if there is none.

     */

    public Exception getException ()

    {

        return getExceptionInternal();

    }

    /**

     * Return the cause of the exception

     *

     * @return Return the cause of the exception

     */

    public Throwable getCause() {

        return super.getCause();

    }

    /**

     * Override toString to pick up any embedded exception.

     *

     * @return A string representation of this exception.

     */

    public String toString ()

    {

        Throwable exception = super.getCause();

        if (exception != null) {

            return super.toString() + "\n" + exception.toString();

        } else {

            return super.toString();

        }

    }

    //////////////////////////////////////////////////////////////////////

    // Internal state.

    //////////////////////////////////////////////////////////////////////

    private static final ObjectStreamField[] serialPersistentFields = {

        new ObjectStreamField( "exception", Exception.class )

    };

    /**

     * Writes "exception" field to the stream.

     *

     * @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("exception", getExceptionInternal());

        out.writeFields();

    }

    /**

     * Reads the "exception" field from the stream.

     * And initializes the "exception" 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();

        Exception exception = (Exception) fields.get("exception", null);

        Throwable superCause = super.getCause();

        // if super.getCause() and 'exception' fields present then always use

        // getCause() value. Otherwise, use 'exception' to initialize cause

        if (superCause == null && exception != null) {

            try {

                super.initCause(exception);

            } catch (IllegalStateException e) {

                throw new InvalidClassException("Inconsistent state: two causes");

            }

        }

    }

    // Internal method to guard against overriding of public getException

    // method by SAXException subclasses

    private Exception getExceptionInternal() {

        Throwable cause = super.getCause();

        if (cause instanceof Exception) {

            return (Exception) cause;

        } else {

            return null;

        }

    }

    // Added serialVersionUID to preserve binary compatibility

    static final long serialVersionUID = 583241635256073760L;

}

// end of SAXException.java