Bug 75711 AstProvider should not create AST if requested by SelectionListenerWithASTManager
3.1 M2 If SelectionListenerWithASTManager waits for an AST and the editor closes we should not create an AST for that one but return null instead.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/ASTProvider.java
}
		/*
		 * @see org.eclipse.ui.IWindowListener#windowOpened(org.eclipse.ui.IWorkbenchWindow)
		 */
		public void windowOpened(IWorkbenchWindow window) {
			window.getPartService().addPartListener(this);
		}
		
		private boolean isActiveEditor(IWorkbenchPartReference ref) {
			return ref != null && isActiveEditor(ref.getPart(false));
		}
		
		private boolean isActiveEditor(IWorkbenchPart part) {
			return part != null && (part == fActiveEditor);
		}
		
		private boolean isJavaEditor(IWorkbenchPartReference ref) {
			if (ref == null)
				return false;
			
			String id= ref.getId();
			return JavaUI.ID_CF_EDITOR.equals(id) || JavaUI.ID_CU_EDITOR.equals(id); 
		}
	}
	
	public static final int AST_LEVEL= AST.JLS3;
	
	private static final String AST_DISPOSED= "org.eclipse.jdt.internal.ui.astDisposed"; 
	private static final String DEBUG_PREFIX= "ASTProvider > ";