Package io.helidon.common.http

Interface Headers

All Superinterfaces:

Parameters

All Known Subinterfaces:

RequestHeaders, ResponseHeaders

public interface Headers
extends Parameters

Extends Parameters interface by adding methods convenient for HTTP headers.

Method Summary

Modifier and Type	Method	Description
java.util.List<java.lang.String>	all(java.lang.String headerName)	Returns an unmodifiable List of all header fields - each element represents a value of a single header field in the request.
default java.util.Optional<java.lang.String>	value(java.lang.String headerName)	Returns a header value as a single String potentially concatenated using comma character from all header fields.
default java.util.List<java.lang.String>	values(java.lang.String headerName)	Returns an unmodifiable List of all comma separated header value parts - Such segmentation is NOT valid for all header semantics, however it is very common.

Methods inherited from interface io.helidon.common.http.Parameters

add, add, addAll, computeIfAbsent, computeSingleIfAbsent, first, put, put, putAll, putIfAbsent, putIfAbsent, remove, toMap, toUnmodifiableParameters

Method Detail

all

java.util.List<java.lang.String> all(java.lang.String headerName)

Returns an unmodifiable List of all header fields - each element represents a value of a single header field in the request. Consider to use value(String) or values(String) method instead.

Always returns a List, which may be empty if the parameter is not present.

Specified by:

all in interface Parameters

Parameters:

headerName - the header name

Returns:

a List of values with zero or greater size

Throws:

java.lang.NullPointerException - if headerName is null

See Also:

value(String), values(String)

value

default java.util.Optional<java.lang.String> value(java.lang.String headerName)

Returns a header value as a single String potentially concatenated using comma character from all header fields.

Accordingly to RFC2616, Message Headers:

Multiple message-header fields with the same field-name MAY be present in a message if and only if the entire field-value for that header field is defined as a comma-separated list [i.e., #(values)]. It MUST be possible to combine the multiple header fields into one "field-name: field-value" pair, without changing the semantics of the message, by appending each subsequent field-value to the first, each separated by a comma.

Parameters:

headerName - the header name

Returns:

all header values concatenated using comma separator

Throws:

java.lang.NullPointerException - if headerName is null

See Also:

all(String), values(String)

values

default java.util.List<java.lang.String> values(java.lang.String headerName)

Returns an unmodifiable List of all comma separated header value parts - Such segmentation is NOT valid for all header semantics, however it is very common. Refer to actual header semantics standard/description before use.

Result is composed from all header fields with requested headerName where each header value is tokenized by a comma character. Tokenization respects value quoting by double-quote character.

Always returns a List, which may be empty if the parameter is not present.

Parameters:

headerName - the header name

Returns:

a List of values with zero or greater size, never null

Throws:

java.lang.NullPointerException - if headerName is null

See Also:

all(String), value(String)