Example usage for java.util.concurrent CompletionStage whenComplete

Introduction

In this page you can find the example usage for java.util.concurrent CompletionStage whenComplete.

Prototype

public CompletionStage<T> whenComplete(BiConsumer<? super T, ? super Throwable> action);

Source Link

Document

Returns a new CompletionStage with the same result or exception as this stage, that executes the given action when this stage completes.

Usage

From source file:fi.minedu.oiva.backend.spring.handler.CompletionStageReturnValueHandler.java

@SuppressWarnings("unchecked")
@Override//from w w  w .  j a v  a 2s.c  o m
public void handleReturnValue(Object returnValue, MethodParameter returnType,
        ModelAndViewContainer mavContainer, NativeWebRequest webRequest) throws Exception {
    if (returnValue == null) {
        mavContainer.setRequestHandled(true);
        return;
    }

    final DeferredResult<Object> deferredResult = new DeferredResult<>();
    WebAsyncUtils.getAsyncManager(webRequest).startDeferredResultProcessing(deferredResult, mavContainer);

    CompletionStage<?> future = (CompletionStage<?>) returnValue;
    future.whenComplete((result, ex) -> {
        if (ex != null) {
            deferredResult.setErrorResult(ex);
        } else {
            deferredResult.setResult(result);
        }
    });
}

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