API for singleton
- ()
by Stuart Sierra
clojure-contrib is now deprecated
clojure-contrib is no longer being developed or maintained.
Rather than a single, monolithic, contributions library, Clojure now has
a set of separate libraries for each unit of functionality. The libraries
are in the Clojure GitHub organization at
https://github.com/clojure.
API documentation of the libraries can be found at
https://clojure.github.io.
If you're looking for a specific function or namespace from the old
clojure-contrib, see
"Where Did Clojure.Contrib Go".
Full namespace name:
clojure.contrib.singleton
Overview
Singleton functions
Public Variables and Functions
global-singleton
function
This library, clojure-contrib, is deprecated. See here for more information.
Usage: (global-singleton f)
Returns a global singleton function. f is a function of no
arguments that creates and returns some object. The singleton
function will call f just once, the first time it is needed, and
cache the value for all subsequent calls.
Warning: global singletons are often unsafe in multi-threaded code.
Consider per-thread-singleton instead.
Source
per-thread-singleton
function
This library, clojure-contrib, is deprecated. See here for more information.
Usage: (per-thread-singleton f)
Returns a per-thread singleton function. f is a function of no
arguments that creates and returns some object. The singleton
function will call f only once for each thread, and cache its value
for subsequent calls from the same thread. This allows you to
safely and lazily initialize shared objects on a per-thread basis.
Warning: due to a bug in JDK 5, it may not be safe to use a
per-thread-singleton in the initialization function for another
per-thread-singleton. See
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=5025230
Source
