PerFieldPostingsFormat
Enables per field postings support.
Note, when extending this class, the name (.getName) is written into the index. In order for the field to be read, the name must resolve to your implementation via .forName. This method uses Java's ServiceLoader to resolve format names.
Files written by each posting format have an additional suffix containing the format name. For example, in a per-field configuration instead of _1.prx filenames would look like _1_Lucene40_0.prx.
See also
Functions
Writes a new segment
Reads a segment. NOTE: by the time this call returns, it must hold open any files it will need to use; else, those files may be deleted. Additionally, required files may be deleted during the execution of this call before there is a chance to open them. Under these circumstances an IOException should be thrown by the implementation. IOExceptions are expected and will automatically cause a retry of the segment opening logic with the newly revised segments.
Returns the postings format that should be used for writing new segments of field.