use of graphql.execution.directives.QueryDirectives in project graphql-java by graphql-java.
the class ExecutionStrategy method fetchField.
/**
* Called to fetch a value for a field from the {@link DataFetcher} associated with the field
* {@link GraphQLFieldDefinition}.
* <p>
* Graphql fragments mean that for any give logical field can have one or more {@link Field} values associated with it
* in the query, hence the fieldList. However the first entry is representative of the field for most purposes.
*
* @param executionContext contains the top level execution parameters
* @param parameters contains the parameters holding the fields to be executed and source object
*
* @return a promise to a fetched object
*
* @throws NonNullableFieldWasNullException in the future if a non null field resolves to a null value
*/
protected CompletableFuture<FetchedValue> fetchField(ExecutionContext executionContext, ExecutionStrategyParameters parameters) {
MergedField field = parameters.getField();
GraphQLObjectType parentType = (GraphQLObjectType) parameters.getExecutionStepInfo().getUnwrappedNonNullType();
GraphQLFieldDefinition fieldDef = getFieldDef(executionContext.getGraphQLSchema(), parentType, field.getSingleField());
GraphQLCodeRegistry codeRegistry = executionContext.getGraphQLSchema().getCodeRegistry();
GraphQLOutputType fieldType = fieldDef.getType();
// if the DF (like PropertyDataFetcher) does not use the arguments of execution step info then dont build any
Supplier<ExecutionStepInfo> executionStepInfo = FpKit.intraThreadMemoize(() -> createExecutionStepInfo(executionContext, parameters, fieldDef, parentType));
Supplier<Map<String, Object>> argumentValues = () -> executionStepInfo.get().getArguments();
Supplier<ExecutableNormalizedField> normalizedFieldSupplier = getNormalizedField(executionContext, parameters, executionStepInfo);
// DataFetchingFieldSelectionSet and QueryDirectives is a supplier of sorts - eg a lazy pattern
DataFetchingFieldSelectionSet fieldCollector = DataFetchingFieldSelectionSetImpl.newCollector(executionContext.getGraphQLSchema(), fieldType, normalizedFieldSupplier);
QueryDirectives queryDirectives = new QueryDirectivesImpl(field, executionContext.getGraphQLSchema(), executionContext.getVariables());
DataFetchingEnvironment environment = newDataFetchingEnvironment(executionContext).source(parameters.getSource()).localContext(parameters.getLocalContext()).arguments(argumentValues).fieldDefinition(fieldDef).mergedField(parameters.getField()).fieldType(fieldType).executionStepInfo(executionStepInfo).parentType(parentType).selectionSet(fieldCollector).queryDirectives(queryDirectives).build();
DataFetcher<?> dataFetcher = codeRegistry.getDataFetcher(parentType, fieldDef);
Instrumentation instrumentation = executionContext.getInstrumentation();
InstrumentationFieldFetchParameters instrumentationFieldFetchParams = new InstrumentationFieldFetchParameters(executionContext, environment, parameters, dataFetcher instanceof TrivialDataFetcher);
InstrumentationContext<Object> fetchCtx = instrumentation.beginFieldFetch(instrumentationFieldFetchParams);
CompletableFuture<Object> fetchedValue;
dataFetcher = instrumentation.instrumentDataFetcher(dataFetcher, instrumentationFieldFetchParams);
ExecutionId executionId = executionContext.getExecutionId();
try {
Object fetchedValueRaw = dataFetcher.get(environment);
fetchedValue = Async.toCompletableFuture(fetchedValueRaw);
} catch (Exception e) {
if (logNotSafe.isDebugEnabled()) {
logNotSafe.debug(String.format("'%s', field '%s' fetch threw exception", executionId, executionStepInfo.get().getPath()), e);
}
fetchedValue = new CompletableFuture<>();
fetchedValue.completeExceptionally(e);
}
fetchCtx.onDispatched(fetchedValue);
return fetchedValue.handle((result, exception) -> {
fetchCtx.onCompleted(result, exception);
if (exception != null) {
return handleFetchingException(executionContext, environment, exception);
} else {
return CompletableFuture.completedFuture(result);
}
}).thenCompose(Function.identity()).thenApply(result -> unboxPossibleDataFetcherResult(executionContext, parameters, result));
}
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