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
*/
	static List compileColumnExpression( String expression )
			throws BirtException
	{
		if ( expression == null || expression.trim( ).length( ) == 0 )
			return new ArrayList( );
		List columnExprList = new ArrayList( );
		columnExprList.clear( );
		Context context = Context.enter( );
		try
		{
			ScriptOrFnNode tree = instance.parse( expression, context );
			instance.CompiledExprFromTree( expression,
					context,
					tree,
					columnExprList );
		}
		catch ( Exception ex )
		{
			throw new CoreException( instance.pluginId,
					ResourceConstants.INVALID_EXPRESSION,
					ex );
		}
		finally
		{
			Context.exit( );
		}
		return columnExprList;
	}
	/**