/*******************************************************************************
 * Copyright (c) 2000, 2005 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     
 * Port to the D Programming language:
 *     Jacob Carlborg <jacob.carlborg@gmail.com>
 *******************************************************************************/
module dwt.DWTError;

import dwt.DWTError;
import dwt.DWT;

import dwt.internal.Library;

import dwt.dwthelper.utils;

/**
 * This runtime exception is thrown whenever a recoverable error
 * occurs internally in DWT. The message text and error code 
 * provide a further description of the problem. The exception
 * has a <code>throwable</code> field which holds the underlying
 * exception that caused the problem (if this information is
 * available (i.e. it may be null)).
 * <p>
 * DWTExceptions are thrown when something fails internally,
 * but DWT is left in a known stable state (eg. a widget call
 * was made from a non-u/i thread, or there is failure while
 * reading an Image because the source file was corrupt).
 * </p>
 *
 * @see DWTError
 */

public class DWTException : Exception {
    /**
     * The DWT error code, one of DWT.ERROR_*.
     */
    public int code;

    /**
     * The underlying throwable that caused the problem,
     * or null if this information is not available.
     */
    public Exception throwable (Exception e) {
        this.next = e;
        return this.next;
    }

    public Exception throwable () {
        return this.next;
    }

    static final long serialVersionUID = 3257282552304842547L;

    /**
     * Constructs a new instance of this class with its 
     * stack trace filled in. The error code is set to an
     * unspecified value.
     */
    public this () {
        this(DWT.ERROR_UNSPECIFIED);
    }

    /**
     * Constructs a new instance of this class with its 
     * stack trace and message filled in. The error code is
     * set to an unspecified value.  Specifying <code>null</code>
     * as the message is equivalent to specifying an empty String.
     *
     * @param message the detail message for the exception
     */
    public this (String message) {
        this(DWT.ERROR_UNSPECIFIED, message);
    }

    /**
     * Constructs a new instance of this class with its 
     * stack trace and error code filled in.
     *
     * @param code the DWT error code
     */
    public this (int code) {
        this(code, DWT.findErrorText(code));
    }

    /**
     * Constructs a new instance of this class with its 
     * stack trace, error code and message filled in.
     * Specifying <code>null</code> as the message is
     * equivalent to specifying an empty String.
     *
     * @param code the DWT error code
     * @param message the detail message for the exception
     */
    public this (int code, String message) {
        super(message);
        this.code = code;
    }

    /**
     * Returns the underlying throwable that caused the problem,
     * or null if this information is not available.
     * <p>
     * NOTE: This method overrides Throwable.getCause() that was
     * added to JDK1.4. It is necessary to override this method
     * in order for inherited printStackTrace() methods to work.
     * </p>
     * @return the underlying throwable
     * 
     * @since 3.1
     */
    public Exception getCause () {
        return throwable;
    }

    /**
     *  Returns the String describing this DWTException object.
     *  <p>
     *  It is combined with the message String of the Throwable
     *  which caused this DWTException (if this information is available).
     *  </p>
     *  @return the error message String of this DWTException object
     */
    public String getMessage () {
        if (throwable is null)
            return super.getMessage();
        return super.getMessage() + " (" + throwable.toString() + ")"; //$NON-NLS-1$ //$NON-NLS-2$
    }

    /**
     * Outputs a printable representation of this exception's
     * stack trace on the standard error stream.
     * <p>
     * Note: printStackTrace(PrintStream) and printStackTrace(PrintWriter)
     * are not provided in order to maintain compatibility with CLDC.
     * </p>
     */
    public void printStackTrace () {
        super.printStackTrace();
        if (Library.JAVA_VERSION < Library.JAVA_VERSION(1, 4, 0) && throwable !is null) {
            System.err.println("*** Stack trace of contained exception ***"); //$NON-NLS-1$
            throwable.printStackTrace();
        }
    }

}