/*
* Copyright © 2012 The Feign Authors ([email protected])
*
* 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
*
* http://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 feign;
import feign.Request.Options;
import java.util.Optional;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;
/** Submits HTTP {@link Request requests} asynchronously, with an optional context. */
@Experimental
public interface AsyncClient {
/**
* Executes the request asynchronously. Calling {@link CompletableFuture#cancel(boolean)} on the
* result may cause the execution to be cancelled / aborted, but this is not guaranteed.
*
* @param request safe to replay
* @param options options to apply to this request
* @param requestContext - the optional context, for example for storing session cookies. The
* client should update this appropriately based on the received response before completing
* the result.
* @return a {@link CompletableFuture} to be completed with the response, or completed
* exceptionally otherwise, for example with an {@link java.io.IOException} on a network error
* connecting to {@link Request#url()}.
*/
CompletableFuture execute(Request request, Options options, Optional requestContext);
class Default implements AsyncClient {
private final Client client;
private final ExecutorService executorService;
public Default(Client client, ExecutorService executorService) {
this.client = client;
this.executorService = executorService;
}
@Override
public CompletableFuture execute(
Request request, Options options, Optional requestContext) {
final CompletableFuture result = new CompletableFuture<>();
final Future> future =
executorService.submit(
() -> {
try {
result.complete(client.execute(request, options));
} catch (final Exception e) {
result.completeExceptionally(e);
}
});
result.whenComplete(
(response, throwable) -> {
if (result.isCancelled()) {
future.cancel(true);
}
});
return result;
}
}
/**
* A synchronous implementation of {@link AsyncClient}
*
* @param - unused context; synchronous clients handle context internally
*/
class Pseudo implements AsyncClient {
private final Client client;
public Pseudo(Client client) {
this.client = client;
}
@Override
public CompletableFuture execute(
Request request, Options options, Optional requestContext) {
final CompletableFuture result = new CompletableFuture<>();
try {
result.complete(client.execute(request, options));
} catch (final Exception e) {
result.completeExceptionally(e);
}
return result;
}
}
}