001/* 002 * Copyright 2002-2018 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.web.client; 018 019import java.io.IOException; 020import java.lang.reflect.Type; 021 022import org.springframework.http.client.ClientHttpResponse; 023import org.springframework.lang.Nullable; 024 025/** 026 * Generic callback interface used by {@link RestTemplate}'s retrieval methods 027 * Implementations of this interface perform the actual work of extracting data 028 * from a {@link ClientHttpResponse}, but don't need to worry about exception 029 * handling or closing resources. 030 * 031 * <p>Used internally by the {@link RestTemplate}, but also useful for 032 * application code. There is one available factory method, see 033 * {@link RestTemplate#responseEntityExtractor(Type)}. 034 * 035 * @author Arjen Poutsma 036 * @since 3.0 037 * @param <T> the data type 038 * @see RestTemplate#execute 039 */ 040@FunctionalInterface 041public interface ResponseExtractor<T> { 042 043 /** 044 * Extract data from the given {@code ClientHttpResponse} and return it. 045 * @param response the HTTP response 046 * @return the extracted data 047 * @throws IOException in case of I/O errors 048 */ 049 @Nullable 050 T extractData(ClientHttpResponse response) throws IOException; 051 052}