“When you bow deeply to the universe, it bows back; when you call out the name of God, it echoes inside you.” ―Morihei Ueshiba
from Jake Wharton
- usually do work when you start or stop listening.
- Sysnchronous or asynchronous.
- Single item, many items, or empty
- single - network request
- many - button click
- empty - save file or database
- terminates with an error or succeeds to completion
- may never terminate
- just an implementation of the Observer pattern
Rxjava
- a set of classes for representing sources of data
- a set of classes for listening to data sources
- A set of methods for modifying and composing the data
Source
- Usually do work when you start or stop listening.
- Synchronous or asynchronous.
- Single item, many items, or empty.
- Terminates with an error or succeeds to completion.
- May never terminate!
- just an implementation of the Observer pattern
sources
- Observable
- Emits 0 to n items
- Terminates with complete or error.
- Does not have backpressure.
- Flowable
- Emits 0 to n items
- Terminates with complete or error.
- Has backpressure
Flowable vs Observable
- backpressure allows you to control how fast a source emits items.
- Rxjava 1.x added backpressure late in the design process
- All types exposed backupressure but not all sources respected it
- Backpressure, like interitance, must be designed for.
Single
- Either succeeds with an item or errors.
- No backpressure support.
Completable
- Either completes or errors. Has no items!
- No backpressure support.
Maybe
- Either succeeds with an item, completes with no items, or errors. - No backpressure support.
Flowable vs Observable
| — | Backpressure | No Backpressure |
|---|---|---|
| 0…n items, complete / error | Flowable | Observable |
| item / complete/error | - | Maybe |
| item / error | - | Single |
| complete / error | - | Completable |
Source Specializations
- Encoding subsets of Observable into the type system
- Single -item or error. think “scalar”
- Completable - Complete or error, think “runnable”.
- Maybe - Item, complete, or error. think “optional”
points ?
- create
- dispose
Operators
- Manipulate or combine data in some way
- Manipulate threading in some way.
- Manipulate emissions in some way.
