Lucene implementation of IndexManager. This is the central entry point
into the Lucene searching API.
author: Mindaugas Idzelis (min@idzelis.com) author: mraible (formatting and making indexDir configurable)
Creates a new lucene index manager. This should only be created once.
Creating the index manager more than once will definately result in
errors. The preferred way of getting an index is through the
RollerContext.
Parameters: indexDir - -the path to the index directory
Get the directory that is used by the lucene index. This method will
return null if there is no index at the directory location. If we are
using a RAM index, the directory will be a ram directory.
Directory The directory containing the index, or null if error.