M2DocParser.java 文件源码

/**
 * Parses while matching an AQL expression.
 * 
 * @param expression
 *            the expression to parse
 * @return the corresponding {@link AstResult}
 */
private AstResult parseWhileAqlExpression(String expression) {
    final IQueryBuilderEngine.AstResult result;

    if (expression != null && expression.length() > 0) {
        AstBuilderListener astBuilder = AQL56Compatibility.createAstBuilderListener(queryEnvironment);
        CharStream input = new UnbufferedCharStream(new StringReader(expression), expression.length());
        QueryLexer lexer = new QueryLexer(input);
        lexer.setTokenFactory(new CommonTokenFactory(true));
        lexer.removeErrorListeners();
        lexer.addErrorListener(astBuilder.getErrorListener());
        TokenStream tokens = new UnbufferedTokenStream<CommonToken>(lexer);
        QueryParser parser = new QueryParser(tokens);
        parser.addParseListener(astBuilder);
        parser.removeErrorListeners();
        parser.addErrorListener(astBuilder.getErrorListener());
        // parser.setTrace(true);
        parser.expression();
        result = astBuilder.getAstResult();
    } else {
        ErrorExpression errorExpression = (ErrorExpression) EcoreUtil
                .create(AstPackage.eINSTANCE.getErrorExpression());
        List<org.eclipse.acceleo.query.ast.Error> errors = new ArrayList<org.eclipse.acceleo.query.ast.Error>(1);
        errors.add(errorExpression);
        final Map<Object, Integer> positions = new HashMap<Object, Integer>();
        if (expression != null) {
            positions.put(errorExpression, Integer.valueOf(0));
        }
        final BasicDiagnostic diagnostic = new BasicDiagnostic();
        diagnostic.add(new BasicDiagnostic(Diagnostic.ERROR, AstBuilderListener.PLUGIN_ID, 0,
                "null or empty string.", new Object[] {errorExpression }));
        result = new AstResult(errorExpression, positions, positions, errors, diagnostic);
    }

    return result;
}