Println

Documentation

Overview

Println subscribes to the Observable and prints every item to os.Stdout while it waits for completion or error.

Returns either the error or nil when the Observable completed normally. Println is performed on the Trampoline scheduler.

Example (Println)

Subscribe to an observable using Println and print all emitted values.

Range(0, 3).Println()

Output:

0
1
2

Index

• Constants
• type Observable
  • func Range(start, count int) Observable
  • func (o Observable) Println(a ...interface{}) error
• type Observer
• type RxError
  • func (e RxError) Error() string
• type Scheduler
  • func NewScheduler() Scheduler
• type Subscriber
  • func NewSubscriber() Subscriber
• type Subscription

Examples

• Package (Println)

Constants

const ErrUnsubscribed = RxError("subscriber unsubscribed")

Unsubscribed is the error returned by wait when the Unsubscribe method is called on the subscription.

Types

type Observable

type Observable func(Observer, Scheduler, Subscriber)

Observable is a function taking an Observer, Scheduler and Subscriber. Calling it will subscribe the Observer to events from the Observable.

func Range

func Range(start, count int) Observable

Range creates an Observable that emits a range of sequential int values. The generated code will do a type conversion from int to interface{}.

func (Observable) Println

func (o Observable) Println(a ...interface{}) error

Println subscribes to the Observable and prints every item to os.Stdout while it waits for completion or error. Returns either the error or nil when the Observable completed normally. Println uses a serial scheduler created with NewScheduler().

type Observer

type Observer func(next interface{}, err error, done bool)

Observer is a function that gets called whenever the Observable has something to report. The next argument is the item value that is only valid when the done argument is false. When done is true and the err argument is not nil, then the Observable has terminated with an error. When done is true and the err argument is nil, then the Observable has completed normally.

type RxError

type RxError string

func (RxError) Error

func (e RxError) Error() string

type Scheduler

type Scheduler = scheduler.Scheduler

Scheduler is used to schedule tasks to support subscribing and observing.

func NewScheduler

func NewScheduler() Scheduler

type Subscriber

type Subscriber interface {
	// A Subscriber is also a Subscription.
	Subscription

	// Add will create and return a new child Subscriber setup in such a way that
	// calling Unsubscribe on the parent will also call Unsubscribe on the child.
	// Calling the Unsubscribe method on the child will NOT propagate to the
	// parent!
	Add() Subscriber

	// OnUnsubscribe will add the given callback function to the subscriber.
	// The callback will be called when either the Unsubscribe of the parent
	// or of the subscriber itself is called. If the subscription was already
	// canceled, then the callback function will just be called immediately.
	OnUnsubscribe(callback func())

	// OnWait will register a callback to  call when subscription Wait is called.
	OnWait(callback func())

	// Done will set the error internally and then cancel the subscription by
	// calling the Unsubscribe method. A nil value for error indicates success.
	Done(err error)

	// Error returns the error set by calling the Done(err) method. As long as
	// the subscriber is still subscribed Error will return nil.
	Error() error
}

Subscriber is a Subscription with management functionality.

func NewSubscriber

func NewSubscriber() Subscriber

New will create and return a new Subscriber.

type Subscription

type Subscription interface {
	// Subscribed returns true when the subscription is currently active.
	Subscribed() bool

	// Unsubscribe will do nothing if the subscription is not active. If the
	// state is still active however, it will be changed to canceled.
	// Subsequently, it will call Unsubscribe on all child subscriptions added
	// through Add, along with all methods added through OnUnsubscribe. When the
	// subscription is canceled by calling Unsubscribe a call to the Wait method
	// will return the error ErrUnsubscribed.
	Unsubscribe()

	// Canceled returns true when the subscription state is canceled.
	Canceled() bool

	// Wait will by default block the calling goroutine and wait for the
	// Unsubscribe method to be called on this subscription.
	// However, when OnWait was called with a callback wait function it will
	// call that instead. Calling Wait on a subscription that has already been
	// canceled will return immediately. If the subscriber was canceled by
	// calling Unsubscribe, then the error returned is ErrUnsubscribed.
	// If the subscriber was terminated by calling Done, then the error
	// returned here is the one passed to Done.
	Wait() error
}

Subscription is an interface that allows code to monitor and control a subscription it received.