org.apache.juneau.http

Class IfRange

java.lang.Object

org.apache.juneau.http.HeaderString

org.apache.juneau.http.IfRange

public final class IfRange
extends HeaderString

Represents a parsed If-Range HTTP request header.

If the entity is unchanged, send me the part(s) that I am missing; otherwise, send me the entire new entity.

Example

If-Range: "737060cd8c284d8af7ad3082f209582d"

RFC2616 Specification

If a client has a partial copy of an entity in its cache, and wishes to have an up-to-date copy of the entire entity in its cache, it could use the Range request-header with a conditional GET (using either or both of If-Unmodified-Since and If-Match.) However, if the condition fails because the entity has been modified, the client would then have to make a second request to obtain the entire current entity-body.

The If-Range header allows a client to "short-circuit" the second request. Informally, its meaning is `if the entity is unchanged, send me the part(s) that I am missing; otherwise, send me the entire new entity'.

If-Range = "If-Range" ":" ( entity-tag | HTTP-date )

If the client has no entity tag for an entity, but does have a Last- Modified date, it MAY use that date in an If-Range header. (The server can distinguish between a valid HTTP-date and any form of entity-tag by examining no more than two characters.) The If-Range header SHOULD only be used together with a Range header, and MUST be ignored if the request does not include a Range header, or if the server does not support the sub-range operation.

If the entity tag given in the If-Range header matches the current entity tag for the entity, then the server SHOULD provide the specified sub-range of the entity using a 206 (Partial content) response. If the entity tag does not match, then the server SHOULD return the entire entity using a 200 (OK) response.

See Also:

• Hypertext Transfer Protocol -- HTTP/1.1

Method Summary

Modifier and Type	Method and Description
Date	asDate() Returns this header value as a Date object.
EntityValidator	asValidator() Returns this header value as an EntityValidator object.
static IfRange	forString(String value) Returns a parsed If-Range header.

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

asString, eq, eqIC, toString

Methods inherited from class java.lang.Object

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

Method Detail

forString

public static IfRange forString(String value)

Returns a parsed If-Range header.

Parameters:

value - The If-Range header string.

Returns:

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

asDate

public Date asDate()

Returns this header value as a Date object.

Returns:

This header value as a Date object, or null if the value is not a date.

asValidator

public EntityValidator asValidator()

Returns this header value as an EntityValidator object.

Returns:

This header value as a EntityValidator object, or null if the value is not an entity validator.