/* java.lang.VMThrowable -- VM support methods for Throwable. Copyright (C) 1998, 1999, 2002, 2004 Free Software Foundation, Inc. This file is part of GNU Classpath. GNU Classpath is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GNU Classpath 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 for more details. You should have received a copy of the GNU General Public License along with GNU Classpath; see the file COPYING. If not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. Linking this library statically or dynamically with other modules is making a combined work based on this library. Thus, the terms and conditions of the GNU General Public License cover the whole combination. As a special exception, the copyright holders of this library give you permission to link this library with independent modules to produce an executable, regardless of the license terms of these independent modules, and to copy and distribute the resulting executable under terms of your choice, provided that you also meet, for each linked independent module, the terms and conditions of the license of that module. An independent module is a module which is not derived from or based on this library. If you modify this library, you may extend this exception to your version of the library, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version. */ package java.lang; import gnu.gcj.runtime.NameFinder; import gnu.gcj.runtime.StackTrace; /** * VM dependent state and support methods Throwable. * It is deliberately package local and final and should only be accessed * by the Throwable class. *
* This is the version used by libgcj (http://gcc.gnu.org/java/).
*
* @author Mark Wielaard (mark@klomp.org)
*/
final class VMThrowable
{
private gnu.gcj.runtime.StackTrace trace;
/**
* Private contructor, create VMThrowables with fillInStackTrace();
*/
private VMThrowable() { }
/**
* Fill in the stack trace with the current execution stack.
* Called by Throwable.fillInStackTrace()
to get the state of
* the VM. Can return null when the VM does not support caputing the VM
* execution state.
*
* @return a new VMThrowable containing the current execution stack trace.
* @see Throwable#fillInStackTrace()
*/
static VMThrowable fillInStackTrace(Throwable t)
{
VMThrowable state = null;
/* FIXME: size of the stack trace is limited to 128 elements.
It's undoubtedly sensible to limit the stack trace, but 128 is
rather arbitrary. It may be better to configure this. */
if (trace_enabled)
{
state = new VMThrowable ();
state.trace = new gnu.gcj.runtime.StackTrace(128);
}
return state;
}
/**
* Returns an StackTraceElement
array based on the execution
* state of the VM as captured by fillInStackTrace
.
* Called by Throwable.getStackTrace()
.
*
* @return a non-null but possible zero length array of StackTraceElement.
* @see Throwable#getStackTrace()
*/
StackTraceElement[] getStackTrace(Throwable t)
{
StackTraceElement[] result;
if (trace != null)
{
NameFinder nameFinder = new NameFinder();
result = nameFinder.lookup(t, trace);
nameFinder.close();
}
else
result = new StackTraceElement[0];
return result;
}
// Setting this flag to false prevents fillInStackTrace() from running.
static boolean trace_enabled = true;
}