To build an AEM component that is able to produce PDF reports using Jasper Reports, you need to use the Jasper Reports API http://jasperreports.sourceforge.net/api/.
The custom AEM Service invokes the operation of the OSGi bundle that uses the Jasper Reports API. Then the service persists the Jasper Report in the AEM DAM by using the AssetManager API, as shown in this illustration.
NOTE; For information about Jasper Reports, see http://community.jaspersoft.com/project/jasperreports-library.
To read this development article, click https://helpx.adobe.com/experience-manager/using/jasper_reports.html.