io.smallrye.mutiny.groups

Class MultiOnFailure<T>

java.lang.Object

io.smallrye.mutiny.groups.MultiOnFailure<T>

Type Parameters:

T - the type of item

public class MultiOnFailure<T>
extends Object

Configures the failure handler.

The upstream multi has sent us a failure, this class lets you decide what need to be done in this case. Typically, you can recover with a fallback item (recoverWithItem(Object)), or with another Multi (recoverWithMulti(Multi)), or simply completes the stream (recoverWithCompletion()). You can also retry (retry()). Maybe, you just want to look at the failure (invoke(Consumer)).

You can configure the type of failure on which your handler is called using:

 
 multi.onFailure(IOException.class).recoverWithItem("boom")
 multi.onFailure(IllegalStateException.class).recoverWithItem("kaboom")
 multi.onFailure(NoMoreDataException.class).recoverWithCompletion()
 multi.onFailure(t -> accept(t)).recoverWithItem("another boom")
 
 

Constructor Summary

Constructors

Constructor and Description
MultiOnFailure(Multi<T> upstream, Predicate<? super Throwable> predicate)

Method Summary

Modifier and Type	Method and Description
Multi<T>	apply(Function<? super Throwable,? extends Throwable> mapper) Deprecated. use transform(Function)
Multi<T>	invoke(Consumer<Throwable> callback) Produces a new Multi invoking the given callback when the upstream Multi emits a failure (matching the predicate if set).
Multi<T>	invokeUni(Function<Throwable,? extends Uni<?>> action) Produces a new Multi invoking the given @{code action} when a failure event is received.
Multi<T>	recoverWithCompletion() Recovers from the received failure (matching the predicate if set) by completing the stream.
Multi<T>	recoverWithItem(Function<? super Throwable,? extends T> function) Recovers from the received failure (matching the predicate if set) by using a item generated by the given function.
Multi<T>	recoverWithItem(Supplier<T> supplier) Recovers from the received failure (matching the predicate if set) by using a item generated by the given supplier.
Multi<T>	recoverWithItem(T fallback) Recovers from the received failure (matching the predicate if set) by using a fallback item.
Multi<T>	recoverWithMulti(Function<? super Throwable,? extends Multi<? extends T>> function) Recovers from the received failure (matching the predicate if set) with another Multi.
Multi<T>	recoverWithMulti(Multi<? extends T> fallback) Recovers from the received failure (matching the predicate if set) with another given Multi.
Multi<T>	recoverWithMulti(Supplier<? extends Multi<? extends T>> supplier) Recovers from the received failure (matching the predicate if set) with another Multi.
MultiRetry<T>	retry() Configures the retry strategy.
Multi<T>	transform(Function<? super Throwable,? extends Throwable> mapper) Produces a new Multi invoking the given function when the current Multi propagates a failure.

Methods inherited from class java.lang.Object

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

Constructor Detail

MultiOnFailure

public MultiOnFailure(Multi<T> upstream,
                      Predicate<? super Throwable> predicate)

Method Detail

invoke

public Multi<T> invoke(Consumer<Throwable> callback)

Produces a new Multi invoking the given callback when the upstream Multi emits a failure (matching the predicate if set).

If the callback throws an exception, a CompositeException is propagated downstream. This exception is composed by the received failure and the thrown exception.

Parameters:

callback - the callback, must not be null

Returns:

the new Multi

invokeUni

public Multi<T> invokeUni(Function<Throwable,? extends Uni<?>> action)

Produces a new Multi invoking the given @{code action} when a failure event is received.

Unlike invoke(Consumer), the passed function returns a Uni. When the produced Uni sends its result, the result is discarded, and the original failure is forwarded downstream. If the produced Uni fails, a CompositeException composed by the original failure and the caught failure is propagated downstream.

If the asynchronous action throws an exception, this exception is propagated downstream as a CompositeException composed with the original failure and the caught exception.

This method preserves the order of the items, meaning that the downstream received the items in the same order as the upstream has emitted them.

Parameters:

action - the function taking the failure and returning a Uni, must not be null

Returns:

the new Multi

apply

@Deprecated
public Multi<T> apply(Function<? super Throwable,? extends Throwable> mapper)

Deprecated. use transform(Function)

Produces a new Multi invoking the given function when the current Multi propagates a failure. The function can transform the received failure into another exception that will be fired as failure downstream.

Parameters:

mapper - the mapper function, must not be null, must not return null

Returns:

the new Multi

transform

public Multi<T> transform(Function<? super Throwable,? extends Throwable> mapper)

Produces a new Multi invoking the given function when the current Multi propagates a failure. The function can transform the received failure into another exception that will be fired as failure downstream.

Parameters:

mapper - the mapper function, must not be null, must not return null

Returns:

the new Multi

recoverWithItem

public Multi<T> recoverWithItem(T fallback)

Recovers from the received failure (matching the predicate if set) by using a fallback item.

Parameters:

fallback - the fallback, can be null

Returns:

the new Multi that would emit the given fallback in case the upstream sends us a failure.

recoverWithItem

public Multi<T> recoverWithItem(Supplier<T> supplier)

Recovers from the received failure (matching the predicate if set) by using a item generated by the given supplier. The supplier is called when the failure is received.

If the supplier throws an exception, a CompositeException containing both the received failure and the thrown exception is propagated downstream.

Parameters:

supplier - the supplier providing the fallback item. Must not be null, must not return null.

Returns:

the new Multi that would emit the produced item in case the upstream sends a failure.

recoverWithItem

public Multi<T> recoverWithItem(Function<? super Throwable,? extends T> function)

Recovers from the received failure (matching the predicate if set) by using a item generated by the given function. The function is called when the failure is received.

If the function throws an exception, a CompositeException containing both the received failure and the thrown exception is propagated downstream.

Parameters:

function - the function providing the fallback item. Must not be null, must not return null.

Returns:

the new Multi that would emit the produced item in case the upstream sends a failure.

recoverWithCompletion

public Multi<T> recoverWithCompletion()

Recovers from the received failure (matching the predicate if set) by completing the stream. Upon failure, it sends the completion event downstream.

Returns:

the new Multi that would complete in case the upstream sends a failure.

recoverWithMulti

public Multi<T> recoverWithMulti(Function<? super Throwable,? extends Multi<? extends T>> function)

Recovers from the received failure (matching the predicate if set) with another Multi. This multi is produced by the given function. The function must not return null.

In case of failure, the downstream switches to the produced Multi.

If the function throws an exception, a CompositeException containing both the received failure and the thrown exception is propagated downstream.

Parameters:

function - the function providing the fallback Multi. Must not be null, must not return null.

Returns:

the new Multi that would emit events from the multi produced by the given function in case the upstream sends a failure.

recoverWithMulti

public Multi<T> recoverWithMulti(Supplier<? extends Multi<? extends T>> supplier)

Recovers from the received failure (matching the predicate if set) with another Multi. This multi is produced by the given function. The supplier must not return null.

In case of failure, the downstream switches to the produced Multi.

If the supplier throws an exception, a CompositeException containing both the received failure and the thrown exception is propagated downstream.

Parameters:

supplier - the function supplier the fallback Multi. Must not be null, must not return null.

Returns:

the new Multi that would emit events from the multi produced by the given supplier in case the upstream sends a failure.

recoverWithMulti

public Multi<T> recoverWithMulti(Multi<? extends T> fallback)

Recovers from the received failure (matching the predicate if set) with another given Multi.

In case of failure, the downstream switches to the given Multi.

Parameters:

fallback - the fallback Multi. Must not be null.

Returns:

the new Multi that would emit events from the passed multi in case the upstream sends a failure.

retry

public MultiRetry<T> retry()

Configures the retry strategy.

Returns:

the object to configure the retry.