Proxy pattern
|
|
In computer programming, a proxy pattern is a software design pattern.
A proxy, in its most general form, is a class functioning as an interface to another thing. The other thing could be anything, a network connection, a large object in memory, a file, ...
A well-known example of the proxy pattern is a reference-counting pointer object, also known as an auto pointer.
(A graphics programming example) Say I have a number of objects, like a tree. I want this tree repeated several times throughout the level, but each time you create a new tree you are allocating more memory that could be used somewhere else, and frankly trees aren't that interesting. How you reduce the memory footprint of all these trees? Easy, instead of making multiple instances of the tree, you create one tree, and then every instance of that class refers to that one tree stored in memory. After there are no more instances of that class, you deallocate the memory for that tree. That's a proxy pattern, you just reference the one object in memory.
See also
- Composite pattern
- Decorator pattern
- Proxy - the term itself appropriately matches this pattern
External links
- Proxy Pattern in Java (http://wiki.java.net/bin/view/Javapedia/ProxyPattern)
- Description from the Pattern Digest (http://patterndigest.com/patterns/Proxy.html)
- Description (http://home.earthlink.net/~huston2/dp/proxy.html) by Vince Huston