public void updateParseTreeFromDoc(VirtualFile grammarFile) { ANTLRv4PluginController controller = ANTLRv4PluginController.getInstance(project); PreviewState previewState = controller.getPreviewState(grammarFile); LOG.info("updateParseTreeFromDoc " + grammarFile + " rule " + previewState.startRuleName); try { final String inputText = previewState.getEditor().getDocument().getText(); ParsingResult results = controller.parseText(grammarFile, inputText); if (results != null) { updateTreeViewer(previewState, results); } else if (previewState.startRuleName == null) { indicateNoStartRuleInParseTreePane(); } else { indicateInvalidGrammarInParseTreePane(); } } catch (IOException ioe) { ioe.printStackTrace(); } }