com.expedia.graphql.hooks

Interface DataFetcherExecutionPredicate

public DataFetcherExecutionPredicate

Perform runtime evaluations of each parameter passed to any KotlinDataFetcher.

The DataFetcherExecutionPredicate is declared globally for all the datafetchers instances and all the parameters. However a more precise logic (at the field level) is possible depending on the implement of evaluate

Because the DataFetcherExecutionPredicate is global, it's not possible to have methods where the type is inferred.

It's recommended to check the type of the different arguments.

Method Summary

Modifier and Type	Method and Description
<T> T	evaluate(T value, kotlin.reflect.KParameter parameter, graphql.schema.DataFetchingEnvironment environment) Perform the predicate logic by evaluating the argument and its value. Then depending on the result either:

Method Detail

evaluate

<T> T evaluate(T value,
               kotlin.reflect.KParameter parameter,
               graphql.schema.DataFetchingEnvironment environment)

Perform the predicate logic by evaluating the argument and its value. Then depending on the result either:

• Return the value itself to continue the datafetcher invocation

• Throw an exception

Parameters:

value - the value to evaluate the predicate against

parameter - the function argument reference containing the KClass and the argument annotations

environment - the DataFetchingEnvironment in which the data fetcher is executed (gives access to field info, execution context etc)