| // *************************************************************************************************************************** |
| // * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file * |
| // * distributed with this work for additional information regarding copyright ownership. The ASF licenses this file * |
| // * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance * |
| // * with the License. You may obtain a copy of the License at * |
| // * * |
| // * http://www.apache.org/licenses/LICENSE-2.0 * |
| // * * |
| // * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an * |
| // * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the * |
| // * specific language governing permissions and limitations under the License. * |
| // *************************************************************************************************************************** |
| package org.apache.juneau.http; |
| |
| import org.apache.juneau.http.annotation.*; |
| |
| /** |
| * Represents a parsed <l>Date</l> HTTP request/response header. |
| * |
| * <p> |
| * The date and time that the message was sent (in "HTTP-date" format as defined by RFC 7231). |
| * |
| * <h5 class='figure'>Example</h5> |
| * <p class='bcode w800'> |
| * Date: Tue, 15 Nov 1994 08:12:31 GMT |
| * </p> |
| * |
| * <h5 class='topic'>RFC2616 Specification</h5> |
| * |
| * The Date general-header field represents the date and time at which the message was originated, having the same |
| * semantics as orig-date in RFC 822. |
| * The field value is an HTTP-date, as described in section 3.3.1; it MUST be sent in RFC 1123 [8]-date format. |
| * <p class='bcode w800'> |
| * Date = "Date" ":" HTTP-date |
| * </p> |
| * |
| * <p> |
| * An example is... |
| * <p class='bcode w800'> |
| * Date: Tue, 15 Nov 1994 08:12:31 GMT |
| * </p> |
| * |
| * <p> |
| * Origin servers MUST include a Date header field in all responses, except in these cases: |
| * <ol> |
| * <li>If the response status code is 100 (Continue) or 101 (Switching Protocols), the response MAY include a Date |
| * header field, at the server's option. |
| * <li>If the response status code conveys a server error, e.g. 500 (Internal Server Error) or 503 (Service |
| * Unavailable), and it is inconvenient or impossible to generate a valid Date. |
| * <li>If the server does not have a clock that can provide a reasonable approximation of the current time, its |
| * responses MUST NOT include a Date header field. |
| * In this case, the rules in section 14.18.1 MUST be followed. |
| * </ol> |
| * |
| * <p> |
| * A received message that does not have a Date header field MUST be assigned one by the recipient if the message will |
| * be cached by that recipient or gatewayed via a protocol which requires a Date. |
| * An HTTP implementation without a clock MUST NOT cache responses without revalidating them on every use. |
| * An HTTP cache, especially a shared cache, SHOULD use a mechanism, such as NTP, to synchronize its clock with a |
| * reliable external standard. |
| * |
| * <p> |
| * Clients SHOULD only send a Date header field in messages that include an entity-body, as in the case of the PUT and |
| * POST requests, and even then it is optional. |
| * A client without a clock MUST NOT send a Date header field in a request. |
| * |
| * <p> |
| * The HTTP-date sent in a Date header SHOULD NOT represent a date and time subsequent to the generation of the message. |
| * It SHOULD represent the best available approximation of the date and time of message generation, unless the |
| * implementation has no means of generating a reasonably accurate date and time. |
| * In theory, the date ought to represent the moment just before the entity is generated. |
| * In practice, the date can be generated at any time during the message origination without affecting its semantic |
| * value. |
| * |
| * <ul class='seealso'> |
| * <li class='extlink'>{@doc RFC2616} |
| * </ul> |
| */ |
| @Header(name="Date") |
| public final class Date extends HeaderDate { |
| |
| /** |
| * Returns a parsed <c>Date</c> header. |
| * |
| * @param value The <c>Date</c> header string. |
| * @return The parsed <c>Date</c> header, or <jk>null</jk> if the string was null. |
| */ |
| public static Date forString(String value) { |
| if (value == null) |
| return null; |
| return new Date(value); |
| } |
| |
| private Date(String value) { |
| super(value); |
| } |
| } |