Pql2Compiler.java 文件源码

@Override
public TransformExpressionTree compileToExpressionTree(String expression) {
  CharStream charStream = new ANTLRInputStream(expression);
  PQL2Lexer lexer = new PQL2Lexer(charStream);
  lexer.setTokenFactory(new CommonTokenFactory(true));
  TokenStream tokenStream = new UnbufferedTokenStream<CommonToken>(lexer);
  PQL2Parser parser = new PQL2Parser(tokenStream);
  parser.setErrorHandler(new BailErrorStrategy());

  // Parse
  ParseTree parseTree = parser.expression();

  ParseTreeWalker walker = new ParseTreeWalker();
  Pql2AstListener listener = new Pql2AstListener(expression, _splitInClause);
  walker.walk(listener, parseTree);

  final AstNode rootNode = listener.getRootNode();
  return TransformExpressionTree.buildTree(rootNode);
}