What is CompositeDisposable in RxJava

Question

I am an Android Student. I want to learn RxJava. My Question is "What is CompositeDisposable in RxJava?". Please describe in detail.

Answer 1

CompositeDisposable is just a class to keep all your disposables in the same place to you can dispose all of then at once. Like:

Disposable disposable1; Disposable disposable2; Disposable disposable3;  CompositeDisposable composite = new CompositeDisposable(); composite.addAll(disposable1, disposable2, disposable3) composite.dispose() 

All of then are disposed

Answer 2

Composite disposable makes disposing (think cancelling early easier). Say you have an activity that has multiple api calls happening at once:

var disposable = api.call1(arg1, arg2).subscribe(...) var disposable2 = api.call2(arg1).subscribe(...) var disposable3 = api.call3().subscribe() 

If you need to prematurely dispose (e.g. the user navigating away from the activity) then you'd need to do this:

disposable.dispose() disposable2.dispose() disposable3.dispose() 

If you instead use a CompositeDisposable you can store all of the disposables in it. Like so:

val composite = CompositeDisposable() composite.add(api.call1(arg1, arg2).subscribe(...)) composite.add(api.call2(arg1).subscribe(...)) composite.add(api.call3().subscribe()) 

And then you can make one dispose call instead:

composite.dispose() 

If you are using kotlin you can use operator overloading to make this look nicer:

  operator fun CompositeDisposable.plusAssign(disposable: Disposable){         this.add(disposable)     } 

Which enables you to express it as:

val composite = CompositeDisposable() composite += api.call1(arg1, arg2).subscribe(...) composite += api.call2(arg1).subscribe(...) composite += api.call3().subscribe() 

Disposable signifies a request (think work being done) and has a method called dispose for disposing of the request.