@Override
    public boolean handles(String token, ScanContext ctx) {
      Token.TYPE lastTokenType = ctx.getLastTokenType();
      if (lastTokenType == Token.TYPE.RELATIONAL_OPERATOR_FUNC) {
        ctx.incrementBracketScore(1);
        return true;
      } else {
        return ctx.getBracketScore() > 0;
      }
    }
Complex Value Operand token handler.
Supports values that span multiple tokens.
ambari-server/src/main/java/org/apache/ambari/server/api/predicate/QueryLexer.java