001/* 002 * Copyright 2002-2014 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.http.client; 018 019import java.io.IOException; 020import java.io.OutputStream; 021 022import org.springframework.http.HttpHeaders; 023import org.springframework.util.Assert; 024 025/** 026 * Abstract base for {@link ClientHttpRequest} that makes sure that headers 027 * and body are not written multiple times. 028 * 029 * @author Arjen Poutsma 030 * @since 3.0 031 */ 032public abstract class AbstractClientHttpRequest implements ClientHttpRequest { 033 034 private final HttpHeaders headers = new HttpHeaders(); 035 036 private boolean executed = false; 037 038 039 @Override 040 public final HttpHeaders getHeaders() { 041 return (this.executed ? HttpHeaders.readOnlyHttpHeaders(this.headers) : this.headers); 042 } 043 044 @Override 045 public final OutputStream getBody() throws IOException { 046 assertNotExecuted(); 047 return getBodyInternal(this.headers); 048 } 049 050 @Override 051 public final ClientHttpResponse execute() throws IOException { 052 assertNotExecuted(); 053 ClientHttpResponse result = executeInternal(this.headers); 054 this.executed = true; 055 return result; 056 } 057 058 /** 059 * Assert that this request has not been {@linkplain #execute() executed} yet. 060 * @throws IllegalStateException if this request has been executed 061 */ 062 protected void assertNotExecuted() { 063 Assert.state(!this.executed, "ClientHttpRequest already executed"); 064 } 065 066 067 /** 068 * Abstract template method that returns the body. 069 * @param headers the HTTP headers 070 * @return the body output stream 071 */ 072 protected abstract OutputStream getBodyInternal(HttpHeaders headers) throws IOException; 073 074 /** 075 * Abstract template method that writes the given headers and content to the HTTP request. 076 * @param headers the HTTP headers 077 * @return the response object for the executed request 078 */ 079 protected abstract ClientHttpResponse executeInternal(HttpHeaders headers) throws IOException; 080 081}