FeatureSource is a set of "high-level" operations for read access. These operations are built on top
of FeatureReader by default, although many implementations make use of optimizations (allowing
PostgisFeatureSource, DB2FeatureSource and other RDMBS feature sources to issue direct SQL statements).
The FeatureSource may implement one of the following subclasses for additional functionality:
- FeatureStore allows read access
- FeatureLocking allows long term transaction support.
Anything you can do using FeatureSource, or FeatureStore can be done using FeatureReader and FeatureWriter. FeatureLocking is considered high level