/**
* {@inheritDoc}
*
* <p>The composite change sends <code>perform</code> to all its <em>enabled</em> children. If one
* of the children throws an exception the remaining children will not receive the <code>perform
* </code> call. In this case the method <code>
* getUndoUntilException</code> can be used to get an undo object containing the undo objects of
* all executed children.
*
* <p>Client are allowed to extend this method.
*/
public Change perform(IProgressMonitor pm) throws CoreException {
fUndoUntilException = null;
List undos = new ArrayList(fChanges.size());
pm.beginTask("", fChanges.size()); // $NON-NLS-1$
pm.setTaskName(RefactoringCoreMessages.CompositeChange_performingChangesTask_name);
Change change = null;
boolean canceled = false;
try {
for (Iterator iter = fChanges.iterator(); iter.hasNext(); ) {
change = (Change) iter.next();
if (canceled && !internalProcessOnCancel(change)) continue;
if (change.isEnabled()) {
Change undoChange = null;
try {
undoChange = change.perform(new SubProgressMonitor(pm, 1));
} catch (OperationCanceledException e) {
canceled = true;
if (!internalContinueOnCancel()) throw e;
undos = null;
}
if (undos != null) {
if (undoChange == null) {
undos = null;
} else {
undos.add(undoChange);
}
}
}
// remove the change from the list of children to give
// the garbage collector the change to collect the change. This
// ensures that the memory consumption doesn't go up when
// producing the undo change tree.
iter.remove();
// Make sure we dispose the change since it will now longer be
// in the list of children when call CompositeChange#dispose()
final Change changeToDispose = change;
SafeRunner.run(
new ISafeRunnable() {
public void run() throws Exception {
changeToDispose.dispose();
}
public void handleException(Throwable exception) {
RefactoringCorePlugin.log(exception);
}
});
}
if (canceled) throw new OperationCanceledException();
if (undos != null) {
Collections.reverse(undos);
return createUndoChange((Change[]) undos.toArray(new Change[undos.size()]));
} else {
return null;
}
} catch (CoreException e) {
handleUndos(change, undos);
internalHandleException(change, e);
throw e;
} catch (RuntimeException e) {
handleUndos(change, undos);
internalHandleException(change, e);
throw e;
}
}
