2aa9e78ddd
* Made minor changes in some patterns such as removed throws clause where not needed, changed incorrect order of arguments in assertEquals * Minor refactorings and code style changes. 1) Removed several use of raw types 2) Removed unnecessary throws clauses 3) Used lambda expressions wherever applicable 4) Used apt assertion methods for readability 5) Use of try with resources wherever applicable 6) Corrected incorrect order of assertXXX arguments * Removed unused import from Promise * Addressed review comments * Addressed checkstyle issue
layout, title, folder, permalink, categories, tags
| layout | title | folder | permalink | categories | tags | ||
|---|---|---|---|---|---|---|---|
| pattern | Semaphore | semaphore | /patterns/semaphore/ | Concurrency |
|
Also known as
Counting Semaphore
Intent
Create a lock which mediates access to a pool of resources. Only a limited number of threads, specified at the creation of the semaphore, can access the resources at any given time. A semaphore which only allows one concurrent access to a resource is called a binary semaphore.
Applicability
Use a Semaphore when
- you have a pool of resources to allocate to different threads
- concurrent access to a resource could lead to a race condition
Credits
- [Semaphore(programming)] (http://en.wikipedia.org/wiki/Semaphore_(programming))
- [Semaphores] (http://tutorials.jenkov.com/java-concurrency/semaphores.html)