assert theAction == DONE || theAction == REDONE || theAction == UNDONE;
assert theAction == DONE || theAction == REDONE || theAction == UNDONE || theAction == ROLL_BACK;
	public ActivityStackEvent( ActivityStack theStack, int theAction )	{		assert theAction == DONE || theAction == REDONE || theAction == UNDONE;		stack = theStack;		action = theAction;	}