(a) a directory input source configured to convert said directory entry between a directory-specific data format and a statement format;

(b) a state database configured to store said directory entry in said statement format;

(c) a mapper component configured to translate said directory entry in said statement format from a class of an ontology of a source directory schema to a class of an ontology of a destination directory schema;

(d) an execution environment configured to interpret a method of a mapping function provided by said mapper component; and

(e) a directory output sink configured to convert said directory entry between said statement format and said directory-specific data format.