Programming: Concurrency Patterns
From wikinotes
Resources
Wikipedia: Concurrency Patterns https://en.wikipedia.org/wiki/Concurrency_pattern
Monitor Object
Manages task execution within a single thread.
Active Object
Decouple thread an object is created in from the thread the object's code will be executed in.
without exposing lock/queue/etc details to the caller.Thread/Subprocess objects are frequently exposed this way (ex:
QtCore.QThread
)
- Caller instantiates a proxy object
- On a method call, the proxy returns a Future/Promise object is created (in background, a request is enqueued)
- In background, a worker performs item from queue
- You may wait/join on the Future/Promise to wait for it to return it's results
Producer/Consumer
Safely parallelized task enqueueing/execution.
- A producer adds data to a synchronized queue
- A variable number of consumers process data from a synchronized queue in a loop
- When producer is finished, send a poison pill for each worker, informing it to break/exit the loop gracefully
- Join on worker threads (wait to close)