forked from ExpediaGroup/graphql-kotlin
/
functionReturnTypes.kt
56 lines (51 loc) · 2.05 KB
/
functionReturnTypes.kt
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/*
* Copyright 2019 Expedia, Inc
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.expediagroup.graphql.generator.types.utils
import com.expediagroup.graphql.generator.extensions.getTypeOfFirstArgument
import com.expediagroup.graphql.generator.extensions.isSubclassOf
import graphql.execution.DataFetcherResult
import org.reactivestreams.Publisher
import java.util.concurrent.CompletableFuture
import kotlin.reflect.KType
/**
* These are the classes that can be returned from data fetchers (ie functions)
* but we only want to expose the wrapped type in the schema.
*
* [Publisher] is used for subscriptions
* [CompletableFuture] is used for asynchronous results
* [DataFetcherResult] is used for returning data and errors in the same response
*
* We can return the following combination of types:
* Valid type T
* Publisher<T>
* DataFetcherResult<T>
* CompletableFuture<T>
* CompletableFuture<DataFetcherResult<T>>
*/
internal fun getWrappedReturnType(returnType: KType): KType {
return when {
returnType.isSubclassOf(Publisher::class) -> returnType.getTypeOfFirstArgument()
returnType.isSubclassOf(DataFetcherResult::class) -> returnType.getTypeOfFirstArgument()
returnType.isSubclassOf(CompletableFuture::class) -> {
val wrappedType = returnType.getTypeOfFirstArgument()
if (wrappedType.isSubclassOf(DataFetcherResult::class)) {
return wrappedType.getTypeOfFirstArgument()
}
wrappedType
}
else -> returnType
}
}