处理ANTLR 4中的错误

Question

在ANTLR4问题中，按照公认答案的错误处理说明，我坚持了以下错误。

public class DescriptiveErrorListener extends BaseErrorListener {
    public static DescriptiveErrorListener INSTANCE = new DescriptiveErrorListener();

    @Override
    public void syntaxError(Recognizer<?, ?> recognizer, Object offendingSymbol,
                        int line, int charPositionInLine,
                        String msg, RecognitionException e)
    {
        if (!REPORT_SYNTAX_ERRORS) {
            return;
        }

        String sourceName = recognizer.getInputStream().getSourceName();
        if (!sourceName.isEmpty()) {
            sourceName = String.format("%s:%d:%d: ", sourceName, line, charPositionInLine);
        }

        System.err.println(sourceName+"line "+line+":"+charPositionInLine+" "+msg);
    }
}

Answer 1

它是在复制并粘贴DescriptiveErrorListener类的同一个文件中声明的。以下是声明：

private static final boolean REPORT_SYNTAX_ERRORS = true;

当值为false时，SyntaxError方法返回而不显示错误。