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.client5.http.classic; 29 30 import java.io.IOException; 31 32 import org.apache.hc.client5.http.impl.ChainElement; 33 import org.apache.hc.client5.http.impl.classic.HttpClientBuilder; 34 import org.apache.hc.client5.http.impl.classic.HttpRequestRetryExec; 35 import org.apache.hc.core5.annotation.Contract; 36 import org.apache.hc.core5.annotation.ThreadingBehavior; 37 import org.apache.hc.core5.http.ClassicHttpRequest; 38 import org.apache.hc.core5.http.ClassicHttpResponse; 39 import org.apache.hc.core5.http.HttpException; 40 41 /** 42 * Abstract request execution handler in a classic client side request execution chain. 43 * Handlers can either be a decorator around another element that implements a cross 44 * cutting aspect or a self-contained executor capable of producing a response 45 * for the given request. 46 * <p> 47 * Important: please note it is required for decorators that implement post execution aspects 48 * or response post-processing of any sort to release resources associated with the response 49 * by calling {@link ClassicHttpResponse#close()} methods in case of an I/O, protocol or 50 * runtime exception, or in case the response is not propagated to the caller. 51 * </p> 52 * <p> 53 * For information regarding the handler chain behaviour in case of a request re-execution, 54 * please refer to the {@link HttpRequestRetryExec} javadoc. 55 * </p> 56 *<p> 57 * Well known request execution handlers could be referred to by name using one of the 58 * {@link ChainElement} enum values. 59 *</p> 60 * 61 * @since 4.3 62 * @see ChainElement 63 * @see HttpClientBuilder#addExecInterceptorFirst(String, ExecChainHandler) 64 * @see HttpClientBuilder#addExecInterceptorBefore(String, String, ExecChainHandler) 65 * @see HttpClientBuilder#addExecInterceptorAfter(String, String, ExecChainHandler) 66 * @see HttpClientBuilder#addExecInterceptorLast(String, ExecChainHandler) 67 */ 68 @Contract(threading = ThreadingBehavior.STATELESS) 69 public interface ExecChainHandler { 70 71 /** 72 * Executes the actual HTTP request. The handler can choose to return 73 * a response message or delegate request execution to the next element 74 * in the execution chain. 75 * 76 * @param request the actual request. 77 * @param scope the execution scope . 78 * @param chain the next element in the request execution chain. 79 */ 80 ClassicHttpResponse execute( 81 ClassicHttpRequest request, 82 ExecChain.Scope scope, 83 ExecChain chain) throws IOException, HttpException; 84 85 }