Package io.micronaut.core.execution

Interface ExecutionFlow<T>

Type Parameters:

T - The flow type

All Known Subinterfaces:

CompletableFutureExecutionFlow<T>, DelayedExecutionFlow<T>, ImperativeExecutionFlow<T>, ReactiveExecutionFlow<T>

@Internal
public interface ExecutionFlow<T>

The execution flow class represents a data flow which state can be represented as a simple imperative flow or an async/reactive. The state can be resolved or lazy - based on the implementation. NOTE: The instance of the flow is not supposed to be used after a mapping operator is used.

Since:

4.0.0

Author:

Denis Stepanov

Method Summary

Modifier and Type	Method	Description
static <T> @NonNull ExecutionFlow<T>	async(@NonNull Executor executor, @NonNull Supplier<? extends ExecutionFlow<T>> supplier)	Create a flow by invoking a supplier asynchronously.
static <T> @NonNull ExecutionFlow<T>	empty()	Create a simple flow representing an empty state.
static <K> @NonNull ExecutionFlow<K>	error(@NonNull Throwable e)	Create a simple flow representing an error.
<R> @NonNull ExecutionFlow<R>	flatMap(@NonNull Function<? super T,? extends ExecutionFlow<? extends R>> transformer)	Map a not-empty value to a new flow.
static <K> @NonNull ExecutionFlow<K>	just(K value)	Create a simple flow representing a value.
<R> @NonNull ExecutionFlow<R>	map(@NonNull Function<? super T,? extends R> transformer)	Map a not-empty value.
void	onComplete(@NonNull BiConsumer<? super T,Throwable> fn)	Invokes a provided function when the flow is resolved, or immediately if it is already done.
@NonNull ExecutionFlow<T>	onErrorResume(@NonNull Function<? super Throwable,? extends ExecutionFlow<? extends T>> fallback)	Supply a new flow if the existing flow is erroneous.
@NonNull ExecutionFlow<T>	putInContext(@NonNull String key, @NonNull Object value)	Store a contextual value.
<R> @NonNull ExecutionFlow<R>	then(@NonNull Supplier<? extends ExecutionFlow<? extends R>> supplier)	Supply a new flow after the existing flow value is resolved.
default @NonNull CompletableFuture<T>	toCompletableFuture()	Converts the existing flow into the completable future.
@Nullable ImperativeExecutionFlow<T>	tryComplete()	Create an ImperativeExecutionFlow from this execution flow, if possible.
default @Nullable Throwable	tryCompleteError()	Alternative to tryComplete() which will unwrap the flow's error.
default T	tryCompleteValue()	Alternative to tryComplete() which will unwrap the flow's value.

Method Details

just

@NonNull
static <K> @NonNull ExecutionFlow<K> just(@Nullable
 K value)

Create a simple flow representing a value.

Type Parameters:

K - The value type

Parameters:

value - The value

Returns:

a new flow

error

@NonNull
static <K> @NonNull ExecutionFlow<K> error(@NonNull
 @NonNull Throwable e)

Create a simple flow representing an error.

Type Parameters:

K - The value type

Parameters:

e - The exception

Returns:

a new flow

empty

@NonNull
static <T> @NonNull ExecutionFlow<T> empty()

Create a simple flow representing an empty state.

Type Parameters:

T - The flow value type

Returns:

a new flow

async

@NonNull
static <T> @NonNull ExecutionFlow<T> async(@NonNull
 @NonNull Executor executor,
 @NonNull
 @NonNull Supplier<? extends ExecutionFlow<T>> supplier)

Create a flow by invoking a supplier asynchronously.

Type Parameters:

T - The flow value type

Parameters:

executor - The executor

supplier - The supplier

Returns:

a new flow

map

@NonNull
<R> @NonNull ExecutionFlow<R> map(@NonNull
 @NonNull Function<? super T,? extends R> transformer)

Map a not-empty value.

Type Parameters:

R - New value Type

Parameters:

transformer - The value transformer

Returns:

a new flow

flatMap

@NonNull
<R> @NonNull ExecutionFlow<R> flatMap(@NonNull
 @NonNull Function<? super T,? extends ExecutionFlow<? extends R>> transformer)

Map a not-empty value to a new flow.

Type Parameters:

R - New value Type

Parameters:

transformer - The value transformer

Returns:

a new flow

then

@NonNull
<R> @NonNull ExecutionFlow<R> then(@NonNull
 @NonNull Supplier<? extends ExecutionFlow<? extends R>> supplier)

Supply a new flow after the existing flow value is resolved.

Type Parameters:

R - New value Type

Parameters:

supplier - The supplier

Returns:

a new flow

onErrorResume

@NonNull
@NonNull ExecutionFlow<T> onErrorResume(@NonNull
 @NonNull Function<? super Throwable,? extends ExecutionFlow<? extends T>> fallback)

Supply a new flow if the existing flow is erroneous.

Parameters:

fallback - The fallback

Returns:

a new flow

putInContext

@NonNull
@NonNull ExecutionFlow<T> putInContext(@NonNull
 @NonNull String key,
 @NonNull
 @NonNull Object value)

Store a contextual value.

Parameters:

key - The key

value - The value

Returns:

a new flow

onComplete

void onComplete(@NonNull
 @NonNull BiConsumer<? super T,Throwable> fn)

Invokes a provided function when the flow is resolved, or immediately if it is already done.

Parameters:

fn - The function

tryComplete

@Nullable
@Nullable ImperativeExecutionFlow<T> tryComplete()

Create an ImperativeExecutionFlow from this execution flow, if possible. The flow will have its result immediately available.

Returns:

The imperative flow, or null if this flow is not complete or does not support this operation

tryCompleteValue

@Nullable
default T tryCompleteValue()

Alternative to tryComplete() which will unwrap the flow's value.

Returns:

The imperative flow then returns its value, or null if this flow is not complete or does not support this operation

Since:

4.3

tryCompleteError

@Nullable
default @Nullable Throwable tryCompleteError()

Alternative to tryComplete() which will unwrap the flow's error.

Returns:

The imperative flow then returns its error, or null if this flow is not complete or does not support this operation

Since:

4.3

toCompletableFuture

@NonNull
default @NonNull CompletableFuture<T> toCompletableFuture()

Converts the existing flow into the completable future.

Returns:

a CompletableFuture that represents the state if this flow.