Package graphql.execution

Class SubscriptionExecutionStrategy

java.lang.Object

graphql.execution.ExecutionStrategy

graphql.execution.SubscriptionExecutionStrategy

@PublicApi
public class SubscriptionExecutionStrategy
extends ExecutionStrategy

An execution strategy that implements graphql subscriptions by using reactive-streams as the output result of the subscription query.

Afterwards each object delivered on that stream will be mapped via running the original selection set over that object and hence producing an ExecutionResult just like a normal graphql query.

See https://spec.graphql.org/draft/#sec-Subscription

See https://www.reactive-streams.org/

Field Summary

Fields inherited from class graphql.execution.ExecutionStrategy

dataFetcherExceptionHandler, executionStepInfoFactory, fieldCollector

Constructor Summary

Constructors

Constructor	Description
SubscriptionExecutionStrategy()
SubscriptionExecutionStrategy(DataFetcherExceptionHandler dataFetcherExceptionHandler)

Method Summary

Modifier and Type	Method	Description
private CompletableFuture<org.reactivestreams.Publisher<Object>>	createSourceEventStream(ExecutionContext executionContext, ExecutionStrategyParameters parameters)
private ExecutionStepInfo	createSubscribedFieldStepInfo(ExecutionContext executionContext, ExecutionStrategyParameters parameters)
CompletableFuture<ExecutionResult>	execute(ExecutionContext executionContext, ExecutionStrategyParameters parameters)	This is the entry point to an execution strategy.
private CompletableFuture<ExecutionResult>	executeSubscriptionEvent(ExecutionContext executionContext, ExecutionStrategyParameters parameters, Object eventPayload)
private ExecutionStrategyParameters	firstFieldOfSubscriptionSelection(ExecutionStrategyParameters parameters)
private String	getRootFieldName(ExecutionStrategyParameters parameters)
private ExecutionResult	wrapWithRootFieldName(ExecutionStrategyParameters parameters, ExecutionResult executionResult)

Methods inherited from class graphql.execution.ExecutionStrategy

assertNonNullFieldPrecondition, assertNonNullFieldPrecondition, completeField, completeValue, completeValueForEnum, completeValueForList, completeValueForList, completeValueForNull, completeValueForObject, completeValueForScalar, createExecutionStepInfo, fetchField, getFieldDef, getFieldDef, getNormalizedField, handleFetchingException, handleNonNullException, mkNameForPath, mkNameForPath, mkNameForPath, resolveField, resolveFieldWithInfo, resolveType, toIterable, unboxPossibleDataFetcherResult

Methods inherited from class java.lang.Object

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

Constructor Details

SubscriptionExecutionStrategy

public SubscriptionExecutionStrategy()

SubscriptionExecutionStrategy

public SubscriptionExecutionStrategy(DataFetcherExceptionHandler dataFetcherExceptionHandler)

Method Details

execute

public CompletableFuture<ExecutionResult> execute(ExecutionContext executionContext,
 ExecutionStrategyParameters parameters)
                                           throws NonNullableFieldWasNullException

Description copied from class: ExecutionStrategy

This is the entry point to an execution strategy. It will be passed the fields to execute and get values for.

Specified by:

execute in class ExecutionStrategy

Parameters:

executionContext - contains the top level execution parameters

parameters - contains the parameters holding the fields to be executed and source object

Returns:

a promise to an ExecutionResult

Throws:

NonNullableFieldWasNullException - in the future if a non null field resolves to a null value

createSourceEventStream

private CompletableFuture<org.reactivestreams.Publisher<Object>> createSourceEventStream(ExecutionContext executionContext,
 ExecutionStrategyParameters parameters)

executeSubscriptionEvent

private CompletableFuture<ExecutionResult> executeSubscriptionEvent(ExecutionContext executionContext,
 ExecutionStrategyParameters parameters,
 Object eventPayload)

wrapWithRootFieldName

private ExecutionResult wrapWithRootFieldName(ExecutionStrategyParameters parameters,
 ExecutionResult executionResult)

getRootFieldName

private String getRootFieldName(ExecutionStrategyParameters parameters)

firstFieldOfSubscriptionSelection

private ExecutionStrategyParameters firstFieldOfSubscriptionSelection(ExecutionStrategyParameters parameters)

createSubscribedFieldStepInfo

private ExecutionStepInfo createSubscribedFieldStepInfo(ExecutionContext executionContext,
 ExecutionStrategyParameters parameters)