RxJava — Schedulers — What, when and how to use it?
Brief introduction of RxJava schedulers.
- Schedulers.io() – This is used to perform non-CPU-intensive operations like making network calls, reading disc/files, database operations, etc., This maintains a pool of threads.
- Schedulers.newThread() – Using this, a new thread will be created each time a task is scheduled. It’s usually suggested not to use scheduler unless there is a very long-running operation. The threads created via newThread() won’t be reused.
- Schedulers.computation() – This schedular can be used to perform CPU-intensive operations like processing huge data, bitmap processing etc., The number of threads created using this scheduler completely depends on number CPU cores available.
- Schedulers.single() – This scheduler will execute all the tasks in sequential order they are added. This can be used when there is a necessity of sequential execution is required.
- Schedulers.immediate() – This scheduler executes the task immediately in a synchronous way by blocking the main thread.
- Schedulers.trampoline() – It executes the tasks in First In – First Out manner. All the scheduled tasks will be executed one by one by limiting the number of background threads to one.
- Schedulers.from() – This allows us to create a scheduler from an executor by limiting the number of threads to be created. When the thread pool is occupied, tasks will be queued.
Example code:
.map(…)
.buffer(10)
.flatMap(…)
.subscribe(….)
could be:
.map(…)
.buffer(10)
.parallel(10)
.runOn(Schedulers.computation())
.flatMap(…)
.sequential()
.subscribe(…)