001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.juneau.rest.client;
018
019/**
020 * A builder interface for configuring and creating {@link HttpTransport} instances.
021 *
022 * <p>
023 * Transport modules (Apache HC, Java HTTP Client, OkHttp, etc.) implement this interface to expose their
024 * configuration options in a transport-agnostic way.  The built transport is then passed to
025 * {@link RestClient.Builder#transport(HttpTransport)}.
026 *
027 * <p>
028 * Example usage:
029 * <p class='bjava'>
030 *    <jc>// Transport-specific options (here, the underlying Apache client) are set on the concrete builder.</jc>
031 *    HttpTransport <jv>transport</jv> = ApacheHc5Transport.<jsm>builder</jsm>()
032 *       .httpClient(<jv>myCloseableHttpClient</jv>)
033 *       .build();
034 *
035 *    RestClient <jv>client</jv> = RestClient.create()
036 *       .transport(<jv>transport</jv>)
037 *       .build();
038 * </p>
039 *
040 * <h5 class='section'>See Also:</h5><ul>
041 *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/NextGenRestClient">Next-Generation REST Client</a>
042 * </ul>
043 *
044 * @since 9.2.1
045 */
046public interface HttpTransportBuilder {
047
048   /**
049    * Builds and returns a configured {@link HttpTransport} instance.
050    *
051    * @return A new transport. Never <jk>null</jk>.
052    */
053   HttpTransport build();
054}