Bug 145022 Provide a utility method to help GUI enhance aggregate on.
DtE will provide a method hasAggregation(String expression) in org.eclipse.birt.core.data.ExpressionUtil, and the return value will be true when the expression is a valid JS expression and it has aggregation defined.
core/org.eclipse.birt.core/src/org/eclipse/birt/core/data/ExpressionParserUtility.java
* @param refNode
	 * @throws BirtException
	 */
	private void compileDirectColRefExpr( Node refNode, ScriptOrFnNode tree,
			List columnExprList ) throws BirtException
	{
		assert ( refNode.getType( ) == Token.GETPROP || refNode.getType( ) == Token.GETELEM );
		Node rowName = refNode.getFirstChild( );
		assert ( rowName != null );
		if ( rowName.getType( ) != Token.NAME )
		{
			if ( refNode.getType( ) == Token.GETPROP
					|| refNode.getType( ) == Token.GETELEM )
			{
				int level = compileOuterColRefExpr( refNode );
				if ( level == -1 )
				{
					compileComplexExpr( refNode, tree, columnExprList );
				}
				else
				{
					Node nextNode = refNode.getLastChild( );
					if ( nextNode.getType( ) == Token.STRING )
					{
						ColumnBinding info = new ColumnBinding( nextNode.getString( ),
								"",
								level );
						columnExprList.add( info );
					}
				}