org.apache.juneau.http.TE Maven / Gradle / Ivy
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package org.apache.juneau.http;
import static org.apache.juneau.http.Constants.*;
import org.apache.juneau.internal.*;
/**
* Represents a parsed TE HTTP request header.
*
*
* The transfer encodings the user agent is willing to accept: the same values as for the response header field
* Transfer-Encoding can be used, plus the "trailers" value (related to the "chunked" transfer method) to notify the
* server it expects to receive additional fields in the trailer after the last, zero-sized, chunk.
*
*
Example
*
* TE: trailers, deflate
*
*
* RFC2616 Specification
*
* The TE request-header field indicates what extension transfer-codings it is willing to accept in the response and
* whether or not it is willing to accept trailer fields in a chunked transfer-coding.
* Its value may consist of the keyword "trailers" and/or a comma-separated list of extension transfer-coding names
* with optional accept parameters (as described in section 3.6).
*
*
* TE = "TE" ":" #( t-codings )
* t-codings = "trailers" | ( transfer-extension [ accept-params ] )
*
*
*
* The presence of the keyword "trailers" indicates that the client is willing to accept trailer fields in a chunked
* transfer-coding, as defined in section 3.6.1.
* This keyword is reserved for use with transfer-coding values even though it does not itself represent a
* transfer-coding.
*
*
* Examples of its use are:
*
* TE: deflate
* TE:
* TE: trailers, deflate;q=0.5
*
*
*
* The TE header field only applies to the immediate connection.
* Therefore, the keyword MUST be supplied within a Connection header field (section 14.10) whenever TE is present in
* an HTTP/1.1 message.
*
*
* A server tests whether a transfer-coding is acceptable, according to a TE field, using these rules:
*
* - The "chunked" transfer-coding is always acceptable.
* If the keyword "trailers" is listed, the client indicates that it is willing to accept trailer fields in the
* chunked response on behalf of itself and any downstream clients.
* The implication is that, if given, the client is stating that either all downstream clients are willing to accept
* trailer fields in the forwarded response, or that it will attempt to buffer the response on behalf of downstream
* recipients.
* Note: HTTP/1.1 does not define any means to limit the size of a chunked response such that a client can be assured
* of buffering the entire response.
*
- If the transfer-coding being tested is one of the transfer-codings listed in the TE field, then it is acceptable
* unless it is accompanied by a qvalue of 0. (As defined in section 3.9, a qvalue of 0 means "not acceptable.")
*
- If multiple transfer-codings are acceptable, then the acceptable transfer-coding with the highest non-zero
* qvalue is preferred.
* The "chunked" transfer-coding always has a qvalue of 1.
*
*
*
* If the TE field-value is empty or if no TE field is present, the only transfer-coding is "chunked".
* A message with no transfer-coding is always acceptable.
*
*
Additional Information
*
*/
public final class TE extends HeaderRangeArray {
private static final Cache cache = new Cache(NOCACHE, CACHE_MAX_SIZE);
/**
* Returns a parsed Accept header.
*
* @param value The Accept header string.
* @return The parsed Accept header, or null if the string was null.
*/
public static TE forString(String value) {
if (value == null)
return null;
TE te = cache.get(value);
if (te == null)
te = cache.put(value, new TE(value));
return te;
}
private TE(String value) {
super(value);
}
}