Apache SpamAssassin is an extensible email filter that is used to identify spam. Once identified, the mail can then be optionally tagged as spam for later filtering. It provides a command line tool to perform filtering, a client-server system to filter large volumes of mail, and Mail::SpamAssassin, a set of Perl modules allowing Apache SpamAssassin to be used in a wide variety of email systems.
Redland is a set of C libraries providing a high-level API for the Resource Description Framework (RDF), allowing it to be stored, parsed, serialized, queried, and manipulated. It has an object-based, modular design and comes with detailed reference documentation and examples. Redland supports all RDF vocabularies such as FOAF, RSS 1.0, Dublin Core, DOAP, and OWL, the query languages SPARQL and RDQL, and all RDF syntaxes including Turtle, RDF/XML, RDF/JSON, RSS, Atom, RDFa, and GRDDL.
Raptor is a C library providing a set of parsers and serializers for Resource Description Framework (RDF) triples by parsing syntaxes into RDF triples and serializing triples into a syntax. The parsers support RDF/XML, N-Triples, GRDDL, and Turtle, and via RSS tag soup: XML RSS, Atom 0.3, and Atom 1.0. The serializers support RDF/XML (3 flavours), Turtle, DOT, N-Triples, RSS 1.0, and Atom 1.0. Raptor handles RDF/XML as used by RDF applications such as RSS 1.0, FOAF, DOAP, Dublin Core, and OWL. It can use either expat or libxml2 for XML parsing, libcurl when available for URI retrieval, and is portable to many POSIX systems.
Funcito is a Java library which simplifies access to your favorite functional programming APIs by wrapping Java methods as the function-type objects defined in those libraries. Rather than creating another functional programming API, Funcito makes it easy to define function-type objects which wrap existing methods. As a result, your code has less noise and clutter of anonymous inner classes, annotations, etc. Your code remains safe for automated refactoring, since there are no String-based reflection or forced naming conventions. The supported frameworks are Google Guava, Jedi, Functional Java, Play! Framework 2, collections-generic, and Netflix RxJava.
The mission of the Apache Portable Runtime (APR) project is to create and maintain software libraries that provide a predictable and consistent interface to underlying platform- specific implementations. The primary goal is to provide an API to which software developers may code and be assured of predictable if not identical behaviour regardless of the platform on which their software is built, relieving them of the need to code special-case conditions to work around or take advantage of platform-specific deficiencies or features.
Studs MVC Framework+ contains a port of Apache's Jakarta Struts to PHP, though the libraries included in the rest of the project are much more vast. In order to implement the Struts port, it was necessary to build a core, object-oriented API in the style of the JDK and the Jakarta Commons, a servlet container to handle HTTP requests and to invoke servlet classes, and finally, a parsing engine for JSP-style template pages. In the end, the result is an environment which is very similar to that provided by a J2EE Web Container, only everything is implemented in PHP. While it was possible to carry over many of the concepts, designs and mechanisms from J2EE, some limitations do exist due to the nature of the PHP programming language, such as the lack of checked exceptions (runtime only).