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See the License for the * 011// * specific language governing permissions and limitations under the License. * 012// *************************************************************************************************************************** 013package org.apache.juneau.http.header; 014 015import java.util.function.*; 016 017import org.apache.juneau.http.annotation.*; 018 019/** 020 * Represents a parsed <l>Expect</l> HTTP request header. 021 * 022 * <p> 023 * Indicates that particular server behaviors are required by the client. 024 * 025 * <h5 class='figure'>Example</h5> 026 * <p class='bcode w800'> 027 * Expect: 100-continue 028 * </p> 029 * 030 * <h5 class='topic'>RFC2616 Specification</h5> 031 * 032 * The Expect request-header field is used to indicate that particular server behaviors are required by the client. 033 * <p class='bcode w800'> 034 * Expect = "Expect" ":" 1#expectation 035 * expectation = "100-continue" | expectation-extension 036 * expectation-extension = token [ "=" ( token | quoted-string ) 037 * *expect-params ] 038 * expect-params = ";" token [ "=" ( token | quoted-string ) ] 039 * </p> 040 * 041 * <p> 042 * A server that does not understand or is unable to comply with any of the expectation values in the Expect field of a 043 * request MUST respond with appropriate error status. 044 * The server MUST respond with a 417 (Expectation Failed) status if any of the expectations cannot be met or, if there 045 * are other problems with the request, some other 4xx status. 046 * 047 * <p> 048 * This header field is defined with extensible syntax to allow for future extensions. 049 * If a server receives a request containing an Expect field that includes an expectation-extension that it does not 050 * support, it MUST respond with a 417 (Expectation Failed) status. 051 * 052 * <p> 053 * Comparison of expectation values is case-insensitive for unquoted tokens (including the 100-continue token), and is 054 * case-sensitive for quoted-string expectation-extensions. 055 * 056 * <p> 057 * The Expect mechanism is hop-by-hop: that is, an HTTP/1.1 proxy MUST return a 417 (Expectation Failed) status if it 058 * receives a request with an expectation that it cannot meet. 059 * However, the Expect request-header itself is end-to-end; it MUST be forwarded if the request is forwarded. 060 * 061 * <p> 062 * Many older HTTP/1.0 and HTTP/1.1 applications do not understand the Expect header. 063 * 064 * <p> 065 * See section 8.2.3 for the use of the 100 (continue) status. 066 * 067 * <ul class='seealso'> 068 * <li class='extlink'>{@doc ExtRFC2616} 069 * </ul> 070 */ 071@Header("Expect") 072public class Expect extends BasicStringHeader { 073 074 private static final long serialVersionUID = 1L; 075 076 /** 077 * Convenience creator. 078 * 079 * @param value 080 * The header value. 081 * <br>Can be any of the following: 082 * <ul> 083 * <li>{@link String} 084 * <li>Anything else - Converted to <c>String</c> then parsed. 085 * </ul> 086 * @return A new {@link Expect} object. 087 */ 088 public static Expect of(Object value) { 089 if (value == null) 090 return null; 091 return new Expect(value); 092 } 093 094 /** 095 * Convenience creator using supplier. 096 * 097 * <p> 098 * Header value is re-evaluated on each call to {@link #getValue()}. 099 * 100 * @param value 101 * The header value supplier. 102 * <br>Can be any of the following: 103 * <ul> 104 * <li>{@link String} 105 * <li>Anything else - Converted to <c>String</c> then parsed. 106 * </ul> 107 * @return A new {@link Expect} object. 108 */ 109 public static Expect of(Supplier<?> value) { 110 if (value == null) 111 return null; 112 return new Expect(value); 113 } 114 115 /** 116 * Constructor. 117 * 118 * @param value 119 * The header value. 120 * <br>Can be any of the following: 121 * <ul> 122 * <li>{@link String} 123 * <li>Anything else - Converted to <c>String</c> then parsed. 124 * <li>A {@link Supplier} of anything on this list. 125 * </ul> 126 */ 127 public Expect(Object value) { 128 super("Expect", value); 129 } 130 131 /** 132 * Constructor 133 * 134 * @param value 135 * The header value. 136 */ 137 public Expect(String value) { 138 this((Object)value); 139 } 140}