Class Once.Builder<E extends GenericEvent>

java.lang.Object

net.dv8tion.jda.api.utils.Once.Builder<E>

Type Parameters:

E - Type of the event listened to

Enclosing class:

Once<E extends GenericEvent>

public static class Once.Builder<E extends GenericEvent>
extends Object

Builds a one-time event listener, can be reused.

Constructor Summary

Constructors

Constructor	Description
Builder(JDA jda, Class<E> eventType)	Creates a builder for a one-time event listener

Method Summary

Modifier and Type	Method	Description
Once.Builder<E>	filter(Predicate<? super E> filter)	Adds an event filter, all filters need to return true for the event to be consumed.
Once.Builder<E>	setTimeoutPool(ScheduledExecutorService timeoutPool)	Sets the thread pool used to schedule timeouts and run its callback.
Task<E>	subscribe(Consumer<E> callback)	Starts listening for the event, once.
Once.Builder<E>	timeout(Duration timeout)	Sets the timeout duration, after which the event is no longer listener for.
Once.Builder<E>	timeout(Duration timeout, Runnable timeoutCallback)	Sets the timeout duration, after which the event is no longer listener for, and the callback is run.

Methods inherited from class Object

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

Constructor Details

Builder

public Builder(@Nonnull
 JDA jda,
 @Nonnull
 Class<E> eventType)

Creates a builder for a one-time event listener

Parameters:

jda - The JDA instance

eventType - The event type to listen for

Throws:

IllegalArgumentException - If any of the parameters is null

Method Details

filter

@Nonnull
public Once.Builder<E> filter(@Nonnull
 Predicate<? super E> filter)

Adds an event filter, all filters need to return true for the event to be consumed.

If the filter throws an exception, this listener will unregister itself.

Parameters:

filter - The filter to add, returns true if the event can be consumed

Returns:

This instance for chaining convenience

Throws:

IllegalArgumentException - If the filter is null

timeout

@Nonnull
public Once.Builder<E> timeout(@Nonnull
 Duration timeout)

Sets the timeout duration, after which the event is no longer listener for.

Parameters:

timeout - The duration after which the event is no longer listener for

Returns:

This instance for chaining convenience

Throws:

IllegalArgumentException - If the timeout is null

timeout

@Nonnull
public Once.Builder<E> timeout(@Nonnull
 Duration timeout,
 @Nullable
 Runnable timeoutCallback)

Sets the timeout duration, after which the event is no longer listener for, and the callback is run.

Parameters:

timeout - The duration after which the event is no longer listener for

timeoutCallback - The callback run after the duration

Returns:

This instance for chaining convenience

Throws:

IllegalArgumentException - If the timeout is null

setTimeoutPool

@Nonnull
public Once.Builder<E> setTimeoutPool(@Nonnull
 ScheduledExecutorService timeoutPool)

Sets the thread pool used to schedule timeouts and run its callback.

By default JDA.getGatewayPool() is used.

Parameters:

timeoutPool - The thread pool to use for timeouts

Returns:

This instance for chaining convenience

Throws:

IllegalArgumentException - If the timeout pool is null

subscribe

@Nonnull
public Task<E> subscribe(@Nonnull
 Consumer<E> callback)

Starts listening for the event, once.

The task will be completed after all filters return true.

Exceptions thrown in blocking and async contexts includes:

• CancellationException - When Task.cancel() is called
• TimeoutException - When the listener has expired
• Any exception thrown by the timeout callback

Returns:

Task returning an event satisfying all preconditions

Throws:

IllegalArgumentException - If the callback is null

See Also:

• Task.onSuccess(Consumer)
• Task.get()