Package io.javago

Class Selector

java.lang.Object

io.javago.Selector

public class Selector
extends Object

The Selector class implements Go's select statement. It implements a select-like mechanism for handling multiple asynchronous tasks. It manages cases involving input channels, output channels, delayed tasks, and a default case. When a Selector's run() method is called, it creates a virtual thread for each case. In the event that one of the cases is a DelayedCase, the delayed case will also reserve a platform thread until either another case in the Selector or the delayed case's method is completed. This means that the amount of delayed cases in a Selector and their duration should be kept to a minimum. When a case is executed, the virtual threads for all other tasks are interrupted and any pending tasks on them are cancelled.

Method Summary

Modifier and Type	Method	Description
<T> Selector	addCase(InputChannel<T> ch, Consumer<T> c)	Adds an InputChannelCase to the selector.
<T> Selector	addCase(OutputChannel<T> ch, T message, Runnable r)	Adds an OutputChannelCase to the selector.
Selector	addCase(Duration d, Runnable r)	Adds a DelayedCase to the selector.
Selector	addDefault(Runnable r)	Adds a default case to the selector.
void	run()	Executes the selector logic.
static Selector	select()	Static factory method to create a new instance of Selector.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

select

public static Selector select()

Static factory method to create a new instance of Selector.

Returns:

a new instance of Selector

addCase

public <T> Selector addCase(InputChannel<T> ch,
 Consumer<T> c)

Adds an InputChannelCase to the selector. The case will execute its Consumer after it receives a message from its associated InputChannel. The message received from the channel will be the input to the consumer.

Type Parameters:

T - the type of messages handled by the input channel

Parameters:

ch - the input channel to monitor

c - the consumer to execute when a message is received

Returns:

this Selector instance for method chaining

addCase

public <T> Selector addCase(OutputChannel<T> ch,
 T message,
 Runnable r)

Adds an OutputChannelCase to the selector. The case will execute its Runnable after it sends a message to its associated OutputChannel.

Type Parameters:

T - the type of message to send through the output channel

Parameters:

ch - the output channel to send the message

message - the message to send through the output channel

r - the callback to execute after sending the message

Returns:

this Selector instance for method chaining

addCase

public Selector addCase(Duration d,
 Runnable r)

Adds a DelayedCase to the selector. The delayed case will reserve a platform thread until either another case in the Selector or the delayed case's method is completed. This means that the amount of delayed cases in a Selector and their duration should be kept to a minimum.

Parameters:

d - the duration to wait before executing the callback

r - the runnable to execute after the delay

Returns:

this Selector instance for method chaining

addDefault

public Selector addDefault(Runnable r)

Adds a default case to the selector. The default case will be executed if every InputChannelCase and OutputChannelCase's channel is empty or full respectively.

Parameters:

r - the runnable to execute as the default case

Returns:

this Selector instance for method chaining

run

public void run()

Executes the selector logic. Creates a virtual thread for each case. In the event that one of the cases is a DelayedCase, the delayed case will also reserve a platform thread until either another case in the Selector or the delayed case's method is completed. This means that the amount of delayed cases in a Selector and their duration should be kept to a minimum. When a case is executed, the virtual threads for all other tasks are interrupted and any pending tasks on them are cancelled.