/*
    * ====================================================================
    * 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 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.NoHttpResponseException;
  import org.apache.http.annotation.Contract;
  import org.apache.http.annotation.ThreadingBehavior;
  import org.apache.http.client.HttpRequestRetryHandler;
  import org.apache.http.client.NonRepeatableRequestException;
  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 failed due to an I/O error
   * 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 RetryExec implements ClientExecChain {
  
      private final Log log = LogFactory.getLog(getClass());
  
      private final ClientExecChain requestExecutor;
      private final HttpRequestRetryHandler retryHandler;
  
      public RetryExec(
              final ClientExecChain requestExecutor,
              final HttpRequestRetryHandler retryHandler) {
          Args.notNull(requestExecutor, "HTTP request executor");
          Args.notNull(retryHandler, "HTTP request retry handler");
          this.requestExecutor = requestExecutor;
          this.retryHandler = retryHandler;
      }
  
      @Override
      public CloseableHttpResponse execute(
              final HttpRoute route,
              final HttpRequestWrapper request,
              final HttpClientContext context,
              final HttpExecutionAware execAware) throws IOException, HttpException {
          Args.notNull(route, "HTTP route");
          Args.notNull(request, "HTTP request");
          Args.notNull(context, "HTTP context");
          final Header[] origheaders = request.getAllHeaders();
          for (int execCount = 1;; execCount++) {
              try {
                  return this.requestExecutor.execute(route, request, context, execAware);
              } catch (final IOException ex) {
                  if (execAware != null && execAware.isAborted()) {
                      this.log.debug("Request has been aborted");
                      throw ex;
                  }
                  if (retryHandler.retryRequest(ex, execCount, context)) {
                      if (this.log.isInfoEnabled()) {
                          this.log.info("I/O exception ("+ ex.getClass().getName() +
                                  ") caught when processing request to "
                                  + route +
                                 ": "
                                 + ex.getMessage());
                     }
                     if (this.log.isDebugEnabled()) {
                         this.log.debug(ex.getMessage(), ex);
                     }
                     if (!RequestEntityProxy.isRepeatable(request)) {
                         this.log.debug("Cannot retry non-repeatable request");
                         throw new NonRepeatableRequestException("Cannot retry request " +
                                 "with a non-repeatable request entity", ex);
                     }
                     request.setHeaders(origheaders);
                     if (this.log.isInfoEnabled()) {
                         this.log.info("Retrying request to " + route);
                     }
                 } else {
                     if (ex instanceof NoHttpResponseException) {
                         final NoHttpResponseException updatedex = new NoHttpResponseException(
                                 route.getTargetHost().toHostString() + " failed to respond");
                         updatedex.setStackTrace(ex.getStackTrace());
                         throw updatedex;
                     }
                     throw ex;
                 }
             }
         }
     }
 
 }