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>User-Agent</l> HTTP request header. 019 * 020 * <p> 021 * The user agent string of the user agent. 022 * 023 * <h5 class='figure'>Example</h5> 024 * <p class='bcode w800'> 025 * User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20100101 Firefox/21.0 026 * </p> 027 * 028 * <h5 class='topic'>RFC2616 Specification</h5> 029 * 030 * The User-Agent request-header field contains information about the user agent originating the request. 031 * This is for statistical purposes, the tracing of protocol violations, and automated recognition of user agents for 032 * the sake of tailoring responses to avoid particular user agent limitations. 033 * User agents SHOULD include this field with requests. 034 * The field can contain multiple product tokens (section 3.8) and comments identifying the agent and any sub-products 035 * which form a significant part of the user agent. 036 * By convention, the product tokens are listed in order of their significance for identifying the application. 037 * 038 * <p class='bcode w800'> 039 * User-Agent = "User-Agent" ":" 1*( product | comment ) 040 * </p> 041 * 042 * <p> 043 * Example: 044 * <p class='bcode w800'> 045 * User-Agent: CERN-LineMode/2.15 libwww/2.17b3 046 * </p> 047 * 048 * <ul class='seealso'> 049 * <li class='extlink'>{@doc RFC2616} 050 * </ul> 051 */ 052@Header("User-Agent") 053public final class UserAgent extends HeaderString { 054 055 /** 056 * Returns a parsed <c>User-Agent</c> header. 057 * 058 * @param value The <c>User-Agent</c> header string. 059 * @return The parsed <c>User-Agent</c> header, or <jk>null</jk> if the string was null. 060 */ 061 public static UserAgent forString(String value) { 062 if (value == null) 063 return null; 064 return new UserAgent(value); 065 } 066 067 private UserAgent(String value) { 068 super(value); 069 } 070}