/*******************************************************************************
* 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
*******************************************************************************/
package org.eclipse.swt;
/**
* This error is thrown whenever an unrecoverable error
* occurs internally in SWT. 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
* throwable that caused the problem (if this information is
* available (i.e. it may be null)).
* <p>
* SWTErrors are thrown when something fails internally which
* either leaves SWT in an unknown state (eg. the o/s call to
* remove an item from a list returns an error code) or when SWT
* is left in a known-to-be-unrecoverable state (eg. it runs out
* of callback resources). SWTErrors should not occur in typical
* programs, although "high reliability" applications should
* still catch them.
* </p><p>
* This class also provides support methods used by SWT to match
* error codes to the appropriate exception class (SWTError,
* SWTException, or IllegalArgumentException) and to provide
* human readable strings for SWT error codes.
* </p>
*
* @see SWTException
* @see SWT#error(int)
*
* @since 1.0
*/
public class SWTError extends Error {
/**
* The SWT error code, one of SWT.ERROR_*.
*/
public int code;
/**
* The underlying throwable that caused the problem,
* or null if this information is not available.
*/
public Throwable throwable;
static final long serialVersionUID = 3833467327105808433L;
/**
* Constructs a new instance of this class with its
* stack trace filled in. The error code is set to an
* unspecified value.
*/
public SWTError () {
this (SWT.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 SWTError (String message) {
this (SWT.ERROR_UNSPECIFIED, message);
}
/**
* Constructs a new instance of this class with its
* stack trace and error code filled in.
*
* @param code the SWT error code
*/
public SWTError (int code) {
this (code, SWT.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 SWT error code
* @param message the detail message for the exception
*/
public SWTError (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 1.0
*/
public Throwable getCause() {
return throwable;
}
/**
* Returns the string describing this SWTError object.
* <p>
* It is combined with the message string of the Throwable
* which caused this SWTError (if this information is available).
* </p>
* @return the error message string of this SWTError object
*/
public String getMessage () {
if (throwable == null) return super.getMessage ();
return super.getMessage () + " (" + throwable.toString () + ")"; //$NON-NLS-1$ //$NON-NLS-2$
}
/**
* Outputs a printable representation of this error'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 ();
// Java versions earlier than 1.4 are not suported
// if (Library.JAVA_VERSION < Library.JAVA_VERSION(1, 4, 0) && throwable != null) {
// System.err.println ("*** Stack trace of contained error ***"); //$NON-NLS-1$
// throwable.printStackTrace ();
// }
}
}