[castor-dev] Patch: SQL Function pass through in Order By Clause

[Low Heng Sin]

Hi all,

I have modify checkOrderClause in ParseTreeWalker.java to allow the use of
sql function in order by clause ( for e.g, select a from mypackage.myclass a
order by Upper(a.name) ). My changes are mark by the tag //{{lowhs and
//lowhs}}. May be someone can review this and see whether it is appropriate
to be incorporated into cvs.

Regards,
Low Heng Sin ( [EMAIL PROTECTED] )


  /**
   * Traverses the order by clause sub-tree and checks for errors.
   *
   * @throws QueryException if an error is detected.
   */
  private void checkOrderClause(ParseTreeNode orderClause)
        throws QueryException {

    if ( orderClause.getToken().getTokenType() != KEYWORD_ORDER )
      throw new QueryException( "checkOrderClause was called on a subtree which is not 
an order clause.");

    //{{lowhs
    ParseTreeNode prevChild = null;
    //lowhs}}
    for (Enumeration e = orderClause.children(); e.hasMoreElements(); ) {
      ParseTreeNode curChild = (ParseTreeNode) e.nextElement();

      int tokenType = curChild.getToken().getTokenType();
      switch (tokenType) {
      case KEYWORD_ASC:
      case KEYWORD_DESC:
          // iterate on child
          curChild = curChild.getChild(0);
          tokenType = curChild.getToken().getTokenType();
      }
      switch (tokenType) {
      case DOT:
          checkProjection( curChild, false, false );
          break;
      case IDENTIFIER:
          //{{lowhs
          if ( curChild.children().hasMoreElements() ) {
            if ( curChild.getChild(0).getToken().getTokenType() == LPAREN ) {
                // A function, skip to next element
                Enumeration arguments = curChild.getChild(0).children();
                while(arguments.hasMoreElements()) {
                      ParseTreeNode nn = (ParseTreeNode)arguments.nextElement();
                      checkWhereClause(nn);
                }
            }
          } else {
                checkField(curChild);
          }
          //lowhs}}
          break;
      //{{lowhs
      case LPAREN:
          if ( ( prevChild == null ) || ( prevChild.getToken().getTokenType() != 
IDENTIFIER ) )
              throw new QueryException("Illegal use of left parenthesis in ORDER BY 
clause.");
          break;
      //lowhs}}
      default:
          throw new QueryException( "Only identifiers, path expressions, and the 
keywords ASC and DESC are allowed in the ORDER BY clause." );
      }
      //{{lowhs
      prevChild = curChild;
      //lowhs}}
    }
  }