org.apache.juneau.http

Class IfUnmodifiedSince

java.lang.Object

org.apache.juneau.http.HeaderDate

org.apache.juneau.http.IfUnmodifiedSince

public final class IfUnmodifiedSince
extends HeaderDate

Represents a parsed If-Unmodified-Since HTTP request header.

Only send the response if the entity has not been modified since a specific time.

Example

If-Unmodified-Since: Sat, 29 Oct 1994 19:43:31 GMT

RFC2616 Specification

The If-Unmodified-Since request-header field is used with a method to make it conditional. If the requested resource has not been modified since the time specified in this field, the server SHOULD perform the requested operation as if the If-Unmodified-Since header were not present.

If the requested variant has been modified since the specified time, the server MUST NOT perform the requested operation, and MUST return a 412 (Precondition Failed).

If-Unmodified-Since = "If-Unmodified-Since" ":" HTTP-date

An example of the field is:

If-Unmodified-Since: Sat, 29 Oct 1994 19:43:31 GMT

If the request normally (i.e., without the If-Unmodified-Since header) would result in anything other than a 2xx or 412 status, the If-Unmodified-Since header SHOULD be ignored.

If the specified date is invalid, the header is ignored.

The result of a request having both an If-Unmodified-Since header field and either an If-None-Match or an If-Modified-Since header fields is undefined by this specification.

See Also:

• Hypertext Transfer Protocol -- HTTP/1.1

Method Summary

Modifier and Type	Method and Description
static IfUnmodifiedSince	forString(String value) Returns a parsed If-Unmodified-Since header.

Methods inherited from class org.apache.juneau.http.HeaderDate

asDate, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Method Detail

forString

public static IfUnmodifiedSince forString(String value)

Returns a parsed If-Unmodified-Since header.

Parameters:

value - The If-Unmodified-Since header string.

Returns:

The parsed If-Unmodified-Since header, or null if the string was null.