It is possible to write custom FeatureFilters by implementing this interface. There are also a wide range of built-in features, and it is possible to build complex queries using FeatureFilter.And, FeatureFilter.Or, and FeatureFilter.Not. Where possible, use of the built-in filters is preferable to writing new filters, since the methods in the FilterUtils class have access to special knowledge about the built-in filter types and how they relate to one another.

If the filter is to be used in a remote process, it is recognized that it may be serialized and sent over to run remotely, rather than each feature being retrieved locally.

In the Java version, FeatureFilter is an interface with a bunch of nested classes and whatnot. Since C# does not allow those inside an interface, the Java FeatureFilter is broken into two parts - this interface along with the static class FeatureFilter to implement the nested classes and static bits.

Original BioJava version by Matthew Pocock and Thomas Down. Port to C# by Doug Swisher.