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Feign Core
There is a newer version: 13.5
/**
 * Copyright 2012-2020 The Feign Authors
 *
 * 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 java.io.IOException;
import java.util.List;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CompletionException;
import java.util.concurrent.TimeUnit;
import java.util.stream.Stream;
import feign.InvocationHandlerFactory.MethodHandler;
import feign.Request.Options;
import feign.codec.Decoder;
import feign.codec.ErrorDecoder;
import static feign.ExceptionPropagationPolicy.UNWRAP;
import static feign.FeignException.errorExecuting;
import static feign.Util.checkNotNull;

final class SynchronousMethodHandler implements MethodHandler {

  private static final long MAX_RESPONSE_BUFFER_SIZE = 8192L;

  private final MethodMetadata metadata;
  private final Target target;
  private final Client client;
  private final Retryer retryer;
  private final List requestInterceptors;
  private final Logger logger;
  private final Logger.Level logLevel;
  private final RequestTemplate.Factory buildTemplateFromArgs;
  private final Options options;
  private final ExceptionPropagationPolicy propagationPolicy;

  // only one of decoder and asyncResponseHandler will be non-null
  private final Decoder decoder;
  private final AsyncResponseHandler asyncResponseHandler;


  private SynchronousMethodHandler(Target target, Client client, Retryer retryer,
      List requestInterceptors, Logger logger,
      Logger.Level logLevel, MethodMetadata metadata,
      RequestTemplate.Factory buildTemplateFromArgs, Options options,
      Decoder decoder, ErrorDecoder errorDecoder, boolean decode404,
      boolean closeAfterDecode, ExceptionPropagationPolicy propagationPolicy,
      boolean forceDecoding) {

    this.target = checkNotNull(target, "target");
    this.client = checkNotNull(client, "client for %s", target);
    this.retryer = checkNotNull(retryer, "retryer for %s", target);
    this.requestInterceptors =
        checkNotNull(requestInterceptors, "requestInterceptors for %s", target);
    this.logger = checkNotNull(logger, "logger for %s", target);
    this.logLevel = checkNotNull(logLevel, "logLevel for %s", target);
    this.metadata = checkNotNull(metadata, "metadata for %s", target);
    this.buildTemplateFromArgs = checkNotNull(buildTemplateFromArgs, "metadata for %s", target);
    this.options = checkNotNull(options, "options for %s", target);
    this.propagationPolicy = propagationPolicy;

    if (forceDecoding) {
      // internal only: usual handling will be short-circuited, and all responses will be passed to
      // decoder directly!
      this.decoder = decoder;
      this.asyncResponseHandler = null;
    } else {
      this.decoder = null;
      this.asyncResponseHandler = new AsyncResponseHandler(logLevel, logger, decoder, errorDecoder,
          decode404, closeAfterDecode);
    }
  }

  @Override
  public Object invoke(Object[] argv) throws Throwable {
    RequestTemplate template = buildTemplateFromArgs.create(argv);
    Options options = findOptions(argv);
    Retryer retryer = this.retryer.clone();
    while (true) {
      try {
        return executeAndDecode(template, options);
      } catch (RetryableException e) {
        try {
          retryer.continueOrPropagate(e);
        } catch (RetryableException th) {
          Throwable cause = th.getCause();
          if (propagationPolicy == UNWRAP && cause != null) {
            throw cause;
          } else {
            throw th;
          }
        }
        if (logLevel != Logger.Level.NONE) {
          logger.logRetry(metadata.configKey(), logLevel);
        }
        continue;
      }
    }
  }

  Object executeAndDecode(RequestTemplate template, Options options) throws Throwable {
    Request request = targetRequest(template);

    if (logLevel != Logger.Level.NONE) {
      logger.logRequest(metadata.configKey(), logLevel, request);
    }

    Response response;
    long start = System.nanoTime();
    try {
      response = client.execute(request, options);
      // ensure the request is set. TODO: remove in Feign 12
      response = response.toBuilder()
          .request(request)
          .requestTemplate(template)
          .build();
    } catch (IOException e) {
      if (logLevel != Logger.Level.NONE) {
        logger.logIOException(metadata.configKey(), logLevel, e, elapsedTime(start));
      }
      throw errorExecuting(request, e);
    }
    long elapsedTime = TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - start);


    if (decoder != null)
      return decoder.decode(response, metadata.returnType());

    CompletableFuture