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1   /*
2    * ====================================================================
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * with the License.  You may obtain a copy of the License at
10   *
11   *   http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing,
14   * software distributed under the License is distributed on an
15   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16   * KIND, either express or implied.  See the License for the
17   * specific language governing permissions and limitations
18   * under the License.
19   * ====================================================================
20   *
21   * This software consists of voluntary contributions made by many
22   * individuals on behalf of the Apache Software Foundation.  For more
23   * information on the Apache Software Foundation, please see
24   * <http://www.apache.org/>.
25   *
26   */
27  
28  package org.apache.hc.core5.http.protocol;
29  
30  import java.io.IOException;
31  
32  import org.apache.hc.core5.annotation.Contract;
33  import org.apache.hc.core5.annotation.ThreadingBehavior;
34  import org.apache.hc.core5.http.EntityDetails;
35  import org.apache.hc.core5.http.HttpException;
36  import org.apache.hc.core5.http.HttpHeaders;
37  import org.apache.hc.core5.http.HttpResponse;
38  import org.apache.hc.core5.http.HttpResponseInterceptor;
39  import org.apache.hc.core5.http.HttpStatus;
40  import org.apache.hc.core5.util.Args;
41  
42  /**
43   * ResponseDate is responsible for adding {@code Date} header to the
44   * outgoing responses. This interceptor is recommended for server side protocol
45   * processors.
46   *
47   * @since 4.0
48   */
49  @Contract(threading = ThreadingBehavior.SAFE)
50  public class ResponseDate implements HttpResponseInterceptor {
51  
52      private static final HttpDateGenerator DATE_GENERATOR = new HttpDateGenerator();
53  
54      public ResponseDate() {
55          super();
56      }
57  
58      @Override
59      public void process(final HttpResponse response, final EntityDetails entity, final HttpContext context)
60              throws HttpException, IOException {
61          Args.notNull(response, "HTTP response");
62          final int status = response.getCode();
63          if ((status >= HttpStatus.SC_OK) &&
64              !response.containsHeader(HttpHeaders.DATE)) {
65              final String httpdate = DATE_GENERATOR.getCurrentDate();
66              response.setHeader(HttpHeaders.DATE, httpdate);
67          }
68      }
69  
70  }