Cascading is a Data Processing API, Process Planner, and Process Scheduler used for defining and executing complex, scale-free, and fault tolerant data processing workflows on an Apache Hadoop cluster. All without having to 'think' in MapReduce.
Cascading is a thin Java library and API that sits on top of Hadoop's MapReduce layer and is executed from the command line like any other Hadoop application.
As a library and API that can be driven from any JVM based language (Jython, JRuby, Groovy, Clojure, etc.), developers can create applications and frameworks that are "operationalized". That is, a single deployable Jar can be used to encapsulate a series of complex and dynamic processes all driven from the command line or a shell. Instead of using external schedulers to glue many individual applications together with XML against each individual command line interface.
The Cascading API approach dramatically simplifies development, regression and integration testing, and deployment of business critical applications on both Amazon Web Services (like Elastic MapReduce) or on dedicated hardware.
Cascading is not a new text based query syntax (like Pig) or another complex system that must be installed on a cluster and maintained (like Hive). But Cascading is both complimentary and a valid alternative to either application.
Clojure is a dynamic programming language that targets the Java Virtual Machine. It is designed to be a general-purpose language, combining the approachability and interactive development of a scripting language with an efficient and robust infrastructure for multithreaded programming. Clojure is a compiled language - it compiles directly to JVM bytecode, yet remains completely dynamic. Every feature supported by Clojure is supported at runtime. Clojure provides easy access to the Java frameworks, with optional type hints and type inference, to ensure that calls to Java can avoid reflection.
Clojure is a dialect of Lisp, and shares with Lisp the code-as-data philosophy and a powerful macro system. Clojure is predominantly a functional programming language, and features a rich set of immutable, persistent data structures. When mutable state is needed, Clojure offers a software transactional memory system and reactive Agent system that ensure clean, correct, multithreaded designs.
I hope you find Clojure's combination of facilities elegant, powerful, practical and fun to use.
The primary forum for discussing Clojure is the Google Group - please join us!
Rich Hickey
he goal of XMLVM is to offer a flexible and extensible cross-compiler toolchain. Instead of cross-compiling on a source code level, XMLVM cross-compiles byte code instructions from Sun Microsystem's virtual machine and Microsoft's Common Language Runtime. The benefit of this approach is that byte code instructions are easier to cross-compile and the difficult parsing of a high-level programming language is left to a regular compiler. In XMLVM, byte code-based programs are represented as XML documents. This allows manipulation and translation of XMLVM-based programs using advanced XML technologies such as XSLT, XQuery, and XPath.