Obtaining IndexReaders
As we have seen already, there are several prerequisites (for example, opening a directory, setting up an analyzer, and writing to index) to prepare an index for a search. Lucene provides the IndexReader
class to access a point-in-time view of an index. It means that you can concurrently write to an index, while an existing IndexReader
is reading without exposing any uncommitted data to the active IndexReader
. This is an important concept to keep in mind because this architecture allows the possibility of providing a seamless transition between index versions by opening a new IndexReader while the old IndexReader
is still servicing a search. The DirectoryReader
is a subclass of IndexReader
, which is the class that provides ...
Get Lucene 4 Cookbook now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.