Package io.opentelemetry.context.propagation

Interface TextMapGetter<C>

Type Parameters:

C - carrier of propagation fields, such as an http request.

public interface TextMapGetter<C>

Interface that allows a TextMapPropagator to read propagated fields from a carrier.

Getter is stateless and allows to be saved as a constant to avoid runtime allocations.

Method Summary

Modifier and Type	Method	Description
String	get(C carrier, String key)	Returns the first value of the given propagation key or returns null.
default Iterator<String>	getAll(C carrier, String key)	If implemented, returns all values for a given key in order, or returns an empty list.
Iterable<String>	keys(C carrier)	Returns all the keys in the given carrier.

Method Details

keys

Iterable<String> keys(C carrier)

Returns all the keys in the given carrier.

Parameters:

carrier - carrier of propagation fields, such as an http request.

Since:

0.10.0

get

@Nullable
String get(@Nullable
 C carrier,
 String key)

Returns the first value of the given propagation key or returns null.

Parameters:

carrier - carrier of propagation fields, such as an http request.

key - the key of the field.

Returns:

the first value of the given propagation key or returns null.

getAll

default Iterator<String> getAll(@Nullable
 C carrier,
 String key)

If implemented, returns all values for a given key in order, or returns an empty list.

The default method returns the first value of the given propagation key as a singleton list, or returns an empty list.

Parameters:

carrier - carrier of propagation fields, such as an http request.

key - the key of the field.

Returns:

all values for a given key in order, or returns an empty list. Default method wraps get() as an Iterator.

Since:

1.50.0