content: /**
   * Copyright (c) 2018-2019, Mihai Emil Andronache
   * All rights reserved.
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are met:
   * 1)Redistributions of source code must retain the above copyright notice,
   * this list of conditions and the following disclaimer.
   * 2)Redistributions in binary form must reproduce the above copyright notice,
   * this list of conditions and the following disclaimer in the documentation
   * and/or other materials provided with the distribution.
   * 3)Neither the name of docker-java-api nor the names of its
   * contributors may be used to endorse or promote products derived from
   * this software without specific prior written permission.
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   */
  package com.amihaiemil.docker;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.Collections;
  import java.util.Properties;
  import org.apache.http.HttpHeaders;
  import org.apache.http.client.protocol.RequestDefaultHeaders;
  import org.apache.http.message.BasicHeader;
  
  /**
   * User Agent Request Header Interceptor.
   * @author Boris Kuzmic (boris.kuzmic@gmail.com)
   * @since 0.0.7
   */
  final class UserAgentRequestHeader extends RequestDefaultHeaders {
  
      /**
       * Config properties file.
       */
      private static final String CONFIG_FILE = "config.properties";
  
      /**
       * Version property key.
       */
      private static final String VERSION_KEY = "build.version";
  
      /**
       * Ctor.
       */
      UserAgentRequestHeader() {
          super(Collections.singletonList(
              new BasicHeader(
                  HttpHeaders.USER_AGENT,
                  String.join(
                      " ",
                      "docker-java-api /",
                      version(),
                      "See https://github.com/amihaiemil/docker-java-api"
                  )
              )
          ));
      }
  
      /**
       * Read current version from property file.
       * @return Build version.
       */
      private static String version() {
          final ClassLoader loader =
              Thread.currentThread().getContextClassLoader();
          final String version;
          final Properties properties = new Properties();
          try (final InputStream inputStream =
                   loader.getResourceAsStream(CONFIG_FILE)){
              properties.load(inputStream);
              version = properties.getProperty(VERSION_KEY);
          } catch (final IOException exception) {
              throw new RuntimeException(
                  String.format("Missing %s file.", CONFIG_FILE)
              );
          }
          return version;
      }
  
  }
  