/**
* Whenever an UndoableEdit happens the edit will either be absorbed by the current compound edit
* or a new compound edit will be started
*/
@Override
public void undoableEditHappened(UndoableEditEvent e) {
// Start a new compound edit
AbstractDocument.DefaultDocumentEvent docEvt = (DefaultDocumentEvent) e.getEdit();
if (compoundEdit == null) {
compoundEdit = startCompoundEdit(e.getEdit());
startCombine = false;
updateDirty();
return;
}
int editLine = ((SyntaxDocument) docEvt.getDocument()).getLineNumberAt(docEvt.getOffset());
// Check for an incremental edit or backspace.
// The Change in Caret position and Document length should both be
// either 1 or -1.
if ((startCombine || Math.abs(docEvt.getLength()) == 1) && editLine == lastLine) {
compoundEdit.addEdit(e.getEdit());
startCombine = false;
updateDirty();
return;
}
// Not incremental edit, end previous edit and start a new one
lastLine = editLine;
compoundEdit.end();
compoundEdit = startCompoundEdit(e.getEdit());
updateDirty();
}
@Override
public void undo() throws CannotUndoException {
// End the edit so future edits don't get absorbed by this edit
if (compoundEdit != null) {
compoundEdit.end();
}
super.undo();
// Always start a new compound edit after an undo
compoundEdit = null;
}
/*
** Each CompoundEdit will store a group of related incremental edits
** (ie. each character typed or backspaced is an incremental edit)
*/
private CompoundEdit startCompoundEdit(UndoableEdit anEdit) {
// Track Caret and Document information of this compound edit
// AbstractDocument.DefaultDocumentEvent docEvt = (DefaultDocumentEvent) anEdit;
// The compound edit is used to store incremental edits
compoundEdit = new MyCompoundEdit();
compoundEdit.addEdit(anEdit);
// The compound edit is added to the UndoManager. All incremental
// edits stored in the compound edit will be undone/redone at once
addEdit(compoundEdit);
return compoundEdit;
}
