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
System.out.println(DEBUG_PREFIX + "created AST for: " + je.getElementName()); 
		if (ast != null && je.equals(fActiveJavaElement))
			cache(ast, je);
		
		return ast;
	}
	/**
	 * Tells whether a reconciler is reconciling the
	 * given Java element.
	 * 
	 * @param javaElement the Java element
	 * @return
	 */
	private boolean isReconciling(IJavaElement javaElement) {
		synchronized (fReconcileLock) {
			return javaElement.equals(fReconcilingJavaElement) && fIsReconciling;		
		}
	}
	
	/**
	 * Creates a new compilation unit AST.
	 * 
	 * @param je the Java element for which to create the AST
	 * @param progressMonitor the progress monitor
	 * @return
	 * @throws	IllegalStateException if the settings provided are
	 * 					insufficient, contradictory, or otherwise unsupported
	 */
	private CompilationUnit createAST(IJavaElement je, IProgressMonitor progressMonitor) {
		ASTParser parser = ASTParser.newParser(AST_LEVEL);