Bug 182680 Use feature of new Aggregation framework of Data Engine.
DataEngine will implement new aggregation framework in 2.2.0RC0. After the implementation is finished Engine should go ahead to use new column bindings in definition of map/highlight.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/LogUtil.java
return toString_OdaDataSetDesign(source);
		}
		else if(source instanceof OdaDataSourceDesign){
			return toString_OdaDataSourceDesign(source);
		}
		else if(source == null)
			return "null";
		else
			return source.toString();
	}
	
	private static String toString_Collection(Object source){
		StringBuffer stringBuffer= new StringBuffer(); 
		Iterator iterator = ( (Collection) source ).iterator( );
		while ( iterator.hasNext( ) )
		{
			stringBuffer.append( toString( iterator.next( ) ) + ", \r\n\t" );
		}
		String str = stringBuffer.toString( );
		if ( str.endsWith( "\t" ) )
		{
			str = str.substring( 0, str.length( ) - 5 );
		}
		return str;
	}
	
	private static String toString_FilterDefinition(Object source){
		return "FilterDefinition("+toString(((FilterDefinition)source).getExpression())+")";
	}
	private static String toString_ConditionalExpression(Object source){