001/* 002 * ==================================================================== 003 * Licensed to the Apache Software Foundation (ASF) under one 004 * or more contributor license agreements. See the NOTICE file 005 * distributed with this work for additional information 006 * regarding copyright ownership. The ASF licenses this file 007 * to you under the Apache License, Version 2.0 (the 008 * "License"); you may not use this file except in compliance 009 * with the License. You may obtain a copy of the License at 010 * 011 * http://www.apache.org/licenses/LICENSE-2.0 012 * 013 * Unless required by applicable law or agreed to in writing, 014 * software distributed under the License is distributed on an 015 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 016 * KIND, either express or implied. See the License for the 017 * specific language governing permissions and limitations 018 * under the License. 019 * ==================================================================== 020 * 021 * This software consists of voluntary contributions made by many 022 * individuals on behalf of the Apache Software Foundation. For more 023 * information on the Apache Software Foundation, please see 024 * <http://www.apache.org/>. 025 * 026 */ 027 028package org.apache.http.impl.client; 029 030import java.io.IOException; 031 032import org.apache.http.HttpEntity; 033import org.apache.http.HttpResponse; 034import org.apache.http.StatusLine; 035import org.apache.http.annotation.Contract; 036import org.apache.http.annotation.ThreadingBehavior; 037import org.apache.http.client.HttpResponseException; 038import org.apache.http.client.ResponseHandler; 039import org.apache.http.util.EntityUtils; 040 041/** 042 * A generic {@link ResponseHandler} that works with the response entity 043 * for successful (2xx) responses. If the response code was >= 300, the response 044 * body is consumed and an {@link HttpResponseException} is thrown. 045 * <p> 046 * If this is used with 047 * {@link org.apache.http.client.HttpClient#execute( 048 * org.apache.http.client.methods.HttpUriRequest, ResponseHandler)}, 049 * HttpClient may handle redirects (3xx responses) internally. 050 * </p> 051 * 052 * @since 4.4 053 */ 054@Contract(threading = ThreadingBehavior.IMMUTABLE) 055public abstract class AbstractResponseHandler<T> implements ResponseHandler<T> { 056 057 /** 058 * Read the entity from the response body and pass it to the entity handler 059 * method if the response was successful (a 2xx status code). If no response 060 * body exists, this returns null. If the response was unsuccessful (>= 300 061 * status code), throws an {@link HttpResponseException}. 062 */ 063 @Override 064 public T handleResponse(final HttpResponse response) 065 throws HttpResponseException, IOException { 066 final StatusLine statusLine = response.getStatusLine(); 067 final HttpEntity entity = response.getEntity(); 068 if (statusLine.getStatusCode() >= 300) { 069 EntityUtils.consume(entity); 070 throw new HttpResponseException(statusLine.getStatusCode(), 071 statusLine.getReasonPhrase()); 072 } 073 return entity == null ? null : handleEntity(entity); 074 } 075 076 /** 077 * Handle the response entity and transform it into the actual response 078 * object. 079 */ 080 public abstract T handleEntity(HttpEntity entity) throws IOException; 081 082}