In the 
v201201 version of the API, we’ve added the ability to perform 
PQL filtering in reports.  As an example of what you can do with this feature, you can now limit the report to only orders and line items you want to see. This will help shorten the report job processing time and reduces the size of the report generated.  The following Java code snippet creates a report job to pull all the line items belonging to an order in your network:
Long orderId = Long.parseLong("INSERT_ORDER_ID_HERE");
// Create statement to filter for an order.
Statement filterStatement = new StatementBuilder(
    "WHERE ORDER_ID = :id").putValue("id", orderId).toStatement();
// Create report job.
ReportJob reportJob = new ReportJob();
// Create report query.
ReportQuery reportQuery = new ReportQuery();
reportQuery.setStatement(filterStatement);
reportQuery.setDateRangeType(DateRangeType.LAST_MONTH);
reportQuery.setDimensions(new Dimension[] {Dimension.LINE_ITEM});
reportQuery.setDimensionAttributes(new DimensionAttribute[] {
DimensionAttribute.ORDER_TRAFFICKER});
reportQuery.setColumns(
    new Column[] {Column.AD_SERVER_IMPRESSIONS, Column.AD_SERVER_REVENUE});
reportJob.setReportQuery(reportQuery);
The ‘ORDER_ID’ field in the WHERE clause is a 
dimension enumeration name. A full breakdown of the supported filter enumerations can be found in the 
documentation.  We encourage the use of 
bind variables to build reusable filter statements, much like other services in the API where PQL is used.  Whenever possible, try to filter on IDs rather than names (i.e. use CITY_CRITERIA_ID over CITY_NAME) since matching by name is case sensitive.  
If you also specify the 
dateRangeType and 
dimensionFilters fields on the 
ReportQuery object, the filter statement will be applied in conjunction (in a logical AND) so that each entry in the report will match all of the filter criteria.  You can check out a full working example in 
Java or language equivalent in our 
client libraries.
This is the first post in the 
Discover DFP API in v201201 series; our next post will cover syncing objects with the new 
lastModifiedDateTime field.  Leave us a comment on the 
forum with any feedback you have for the API or topics you would like to see in the discover series.