/*
    * ====================================================================
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   */
  
  package org.apache.http.impl.execchain;
  
  import java.io.IOException;
  import java.io.InterruptedIOException;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.http.Header;
  import org.apache.http.HttpException;
  import org.apache.http.annotation.Contract;
  import org.apache.http.annotation.ThreadingBehavior;
  import org.apache.http.client.ServiceUnavailableRetryStrategy;
  import org.apache.http.client.methods.CloseableHttpResponse;
  import org.apache.http.client.methods.HttpExecutionAware;
  import org.apache.http.client.methods.HttpRequestWrapper;
  import org.apache.http.client.protocol.HttpClientContext;
  import org.apache.http.conn.routing.HttpRoute;
  import org.apache.http.util.Args;
  
  /**
   * Request executor in the request execution chain that is responsible
   * for making a decision whether a request that received a non-2xx response
   * from the target server should be re-executed.
   * <p>
   * Further responsibilities such as communication with the opposite
   * endpoint is delegated to the next executor in the request execution
   * chain.
   * </p>
   *
   * @since 4.3
   */
  @Contract(threading = ThreadingBehavior.IMMUTABLE_CONDITIONAL)
  public class ServiceUnavailableRetryExec implements ClientExecChain {
  
      private final Log log = LogFactory.getLog(getClass());
  
      private final ClientExecChain requestExecutor;
      private final ServiceUnavailableRetryStrategy retryStrategy;
  
      public ServiceUnavailableRetryExec(
              final ClientExecChain requestExecutor,
              final ServiceUnavailableRetryStrategy retryStrategy) {
          super();
          Args.notNull(requestExecutor, "HTTP request executor");
          Args.notNull(retryStrategy, "Retry strategy");
          this.requestExecutor = requestExecutor;
          this.retryStrategy = retryStrategy;
      }
  
      @Override
      public CloseableHttpResponse execute(
              final HttpRoute route,
              final HttpRequestWrapper request,
              final HttpClientContext context,
              final HttpExecutionAware execAware) throws IOException, HttpException {
          final Header[] origheaders = request.getAllHeaders();
          for (int c = 1;; c++) {
              final CloseableHttpResponse response = this.requestExecutor.execute(
                      route, request, context, execAware);
              try {
                  if (this.retryStrategy.retryRequest(response, c, context)
                          && RequestEntityProxy.isRepeatable(request)) {
                      response.close();
                      final long nextInterval = this.retryStrategy.getRetryInterval();
                      if (nextInterval > 0) {
                          try {
                              this.log.trace("Wait for " + nextInterval);
                              Thread.sleep(nextInterval);
                          } catch (final InterruptedException e) {
                              Thread.currentThread().interrupt();
                              throw new InterruptedIOException();
                          }
                     }
                     request.setHeaders(origheaders);
                 } else {
                     return response;
                 }
             } catch (final RuntimeException ex) {
                 response.close();
                 throw ex;
             }
         }
     }
 
 }