Yes, parent/child (nested mail merge regions) is one of those highly demanded features that is available in Aspose.Words for .NET and not yet available in Aspose.Words for Java. And yes, this feature is going to be available for Java very soon, when our autoporting project is complete.
BTW, there are only 16 files remain to be made autoportable.
Today a small technical article that describes challenges and solutions we came across when making the Aspose.Words MailMerge autoportable to Java.
Overview
To run a mail merge in Aspose.Words requires a “mail merge data source”. Mail merge data sources in Aspose.Words are completely abstracted via the IMailMergeDataSource and IMailMergeDataSourceRoot interfaces. The abstraction of mail merge data sources via interfaces allows the user to feed any data on any platform into a document template during mail merge. For example, the user can implement a mail merge data source to retrieve data from an XML document or from a business object or a collection of objects.
Although implementing mail merge data sources for Aspose.Words is easy, most of the users don’t need this flexibility. Most of the users have their data in a “standard” database access library on their platform. Therefore Aspose.Words implements the “standard” mail merge data sources and allows the user to use them seamlessly. On .NET the database access technoligy is ADO.NET and Aspose.Words allows to mail merge from DataTable, DataSet and other objects (more info below). On Java the database access technology is JDBC and Aspose.Words allows to mail merge from ResultSet objects.
Obviously, ADO.NET and JDBC both are platform-specific technologies and we cannot expect to automatically port code that accesses ADO.NET objects to Java. But nevertherless, I wanted to make sure that as much code is autoportable and only the thin layer of platform-specific details is manually coded. At the same time, the public API should be smooth on both platforms.