ShowAmbigTreesDialog.java 文件源码

public static void popupLookaheadTreesDialog(PreviewState previewState, LookaheadEventInfo lookaheadInfo) {
    // pop up subtrees for lookahead
    ShowAmbigTreesDialog dialog = new ShowAmbigTreesDialog();
    ParserInterpreter parser = (ParserInterpreter) previewState.parsingResult.parser;
    int startRuleIndex = parser.getRuleIndex(previewState.startRuleName);
    List<ParserRuleContext> lookaheadParseTrees =
        GrammarParserInterpreter.getLookaheadParseTrees(previewState.g,
                                                        parser,
                                                        parser.getTokenStream(),
                                                        startRuleIndex,
                                                        lookaheadInfo.decision,
                                                        lookaheadInfo.startIndex,
                                                        lookaheadInfo.stopIndex);
    if ( parser.getNumberOfSyntaxErrors()>0 ) {
        // should be no errors for ambiguities, unless original
        // input itself has errors. Just display error in this case.
        JBPanel errPanel = new JBPanel(new BorderLayout());
        errPanel.add(new JBLabel("Cannot display lookahead trees while there are syntax errors in your input."));
        dialog.treeScrollPane.setViewportView(errPanel);
        lookaheadParseTrees = null;
    }
    if ( lookaheadParseTrees!=null ) {
        Interval range = Interval.of(lookaheadInfo.startIndex, lookaheadInfo.stopIndex);
        String phrase = parser.getTokenStream().getText(range);
        if ( phrase.length()>MAX_PHRASE_WIDTH ) {
            phrase = phrase.substring(0, MAX_PHRASE_WIDTH)+"...";
        }
        String title = lookaheadParseTrees.size()+
            " Interpretations of Lookahead Phrase: "+
            phrase;
        dialog.ambigPhraseLabel.setText(title);
        dialog.setTrees(previewState, lookaheadParseTrees, title, lookaheadInfo.predictedAlt-1,
                        lookaheadInfo.startIndex, lookaheadInfo.stopIndex, false);
    }
    dialog.pack();
    dialog.setVisible(true);
}