Prevayler is an
open-source
Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use the source code, design documents, or content of the product. The open-source model is a decentralized sof ...
(
BSD
The Berkeley Software Distribution or Berkeley Standard Distribution (BSD) is a discontinued operating system based on Research Unix, developed and distributed by the Computer Systems Research Group (CSRG) at the University of California, Be ...
)
system-prevalence layer for
Java
Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's mo ...
: it transparently persists
plain old Java objects. It is an in-RAM database backed by snapshots of the system via object
serialization
In computing, serialization (or serialisation) is the process of translating a data structure or object state into a format that can be stored (e.g. files in secondary storage devices, data buffers in primary storage devices) or transmitted (e ...
, which are loaded after a system crash to restore state. Changes to data happen via transaction operations on objects made from serializable classes. Prevayler's development was started by Klaus Wuestefeld.
Read operations are three to four orders of magnitude faster with Prevayler when compared to traditional database systems since all objects are always in
RAM
Ram, ram, or RAM may refer to:
Animals
* A male sheep
* Ram cichlid, a freshwater tropical fish
People
* Ram (given name)
* Ram (surname)
* Ram (director) (Ramsubramaniam), an Indian Tamil film director
* RAM (musician) (born 1974), Dutch
...
and in-process.
Prevayler requires enough RAM to keep the entire system state.
References
Works cited
*
See also
*
memcached
Memcached (pronounced variously ''mem-cash-dee'' or ''mem-cashed'') is a general-purpose distributed memory caching, memory-caching system. It is often used to speed up dynamic database-driven websites by caching data and Object (computer science) ...
External links
Official WebsiteSourceForge project
{{Database-software-stub
Free memory management software
Java (programming language)
Persistence