001// *************************************************************************************************************************** 002// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file * 003// * distributed with this work for additional information regarding copyright ownership. The ASF licenses this file * 004// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance * 005// * with the License. You may obtain a copy of the License at * 006// * * 007// * http://www.apache.org/licenses/LICENSE-2.0 * 008// * * 009// * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an * 010// * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the * 011// * specific language governing permissions and limitations under the License. * 012// *************************************************************************************************************************** 013package org.apache.juneau.http; 014 015import org.apache.juneau.http.annotation.*; 016 017/** 018 * Represents a parsed <l>Max-Forwards</l> HTTP request header. 019 * 020 * <p> 021 * Limit the number of times the message can be forwarded through proxies or gateways. 022 * 023 * <h5 class='figure'>Example</h5> 024 * <p class='bcode w800'> 025 * Max-Forwards: 10 026 * </p> 027 * 028 * <h5 class='topic'>RFC2616 Specification</h5> 029 * 030 * The Max-Forwards request-header field provides a mechanism with the TRACE (section 9.8) and OPTIONS (section 9.2) 031 * methods to limit the number of proxies or gateways that can forward the request to the next inbound server. 032 * This can be useful when the client is attempting to trace a request chain which appears to be failing or looping in 033 * mid-chain. 034 * 035 * <p class='bcode w800'> 036 * Max-Forwards = "Max-Forwards" ":" 1*DIGIT 037 * </p> 038 * 039 * <p> 040 * The Max-Forwards value is a decimal integer indicating the remaining number of times this request message may be 041 * forwarded. 042 * 043 * <p> 044 * Each proxy or gateway recipient of a TRACE or OPTIONS request containing a Max-Forwards header field MUST check and 045 * update its value prior to forwarding the request. 046 * If the received value is zero (0), the recipient MUST NOT forward the request; instead, it MUST respond as the final 047 * recipient. 048 * If the received Max-Forwards value is greater than zero, then the forwarded message MUST contain an updated 049 * Max-Forwards field with a value decremented by one (1). 050 * 051 * <p> 052 * The Max-Forwards header field MAY be ignored for all other methods defined by this specification and for any 053 * extension methods for which it is not explicitly referred to as part of that method definition. 054 * 055 * <ul class='seealso'> 056 * <li class='extlink'>{@doc RFC2616} 057 * </ul> 058 */ 059@Header("Max-Forwards") 060public final class MaxForwards extends HeaderInteger { 061 062 /** 063 * Constructor. 064 * 065 * @param value The value for this header. 066 */ 067 public MaxForwards(Integer value) { 068 super(value); 069 } 070 071 /** 072 * Returns a parsed <c>Max-Forwards</c> header. 073 * 074 * @param value The <c>Max-Forwards</c> header string. 075 * @return The parsed <c>Max-Forwards</c> header, or <jk>null</jk> if the string was null. 076 */ 077 public static MaxForwards forString(String value) { 078 if (value == null) 079 return null; 080 return new MaxForwards(value); 081 } 082 083 private MaxForwards(String value) { 084 super(value); 085 } 086}