Package org.apache.juneau.http.header

Class Expect

java.lang.Object
org.apache.juneau.http.header.BasicHeader
org.apache.juneau.http.header.BasicStringHeader
org.apache.juneau.http.header.Expect
All Implemented Interfaces:
Serializable, Cloneable, Header, NameValuePair
@Header("Expect") public class Expect extends BasicStringHeader
Represents a parsed Expect HTTP request header.

Indicates that particular server behaviors are required by the client.

Example

Expect: 100-continue

RFC2616 Specification
The Expect request-header field is used to indicate that particular server behaviors are required by the client.

Expect = "Expect" ":" 1#expectation expectation = "100-continue" | expectation-extension expectation-extension = token [ "=" ( token | quoted-string ) *expect-params ] expect-params = ";" token [ "=" ( token | quoted-string ) ]

A server that does not understand or is unable to comply with any of the expectation values in the Expect field of a request MUST respond with appropriate error status. The server MUST respond with a 417 (Expectation Failed) status if any of the expectations cannot be met or, if there are other problems with the request, some other 4xx status.

This header field is defined with extensible syntax to allow for future extensions. If a server receives a request containing an Expect field that includes an expectation-extension that it does not support, it MUST respond with a 417 (Expectation Failed) status.

Comparison of expectation values is case-insensitive for unquoted tokens (including the 100-continue token), and is case-sensitive for quoted-string expectation-extensions.

The Expect mechanism is hop-by-hop: that is, an HTTP/1.1 proxy MUST return a 417 (Expectation Failed) status if it receives a request with an expectation that it cannot meet. However, the Expect request-header itself is end-to-end; it MUST be forwarded if the request is forwarded.

Many older HTTP/1.0 and HTTP/1.1 applications do not understand the Expect header.

See section 8.2.3 for the use of the 100 (continue) status.

See Also:

  • Constructor Details

    • Expect

      public Expect(String value)
      Constructor.
      Parameters:
      value - The header value.
      Can be null.

    • Expect

      public Expect(Supplier<String> value)
      Constructor with delayed value.

      Header value is re-evaluated on each call to BasicStringHeader.getValue().

      Parameters:
      value - The supplier of the header value.
      Can be null.

  • Method Details

    • of

      public static Expect of(String value)
      Static creator.
      Parameters:
      value - The header value.
      Can be null.
      Returns:
      A new header bean, or null if the value is null.

    • of

      public static Expect of(Supplier<String> value)
      Static creator with delayed value.

      Header value is re-evaluated on each call to BasicStringHeader.getValue().

      Parameters:
      value - The supplier of the header value.
      Can be null.
      Returns:
      A new header bean, or null if the value is null.