Interface HttpTransportObserver

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface HttpTransportObserver

Protocol-neutral observation of HTTP transport lifecycle.

Callbacks must not block. Lifecycle events for one connection are published sequentially as specified by HttpTransportObserver.ConnectionObservation. Callbacks for different connections may be invoked concurrently, so implementations must be thread safe. Observation must not affect protocol or transport behavior. Observer callbacks are passive and must not directly or indirectly invoke lifecycle methods on a HttpTransportObserver.ConnectionObservation, HttpTransportObserver.HandshakeObservation, or HttpTransportObserver.StreamObservation; callback reentry is not supported.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static interface	HttpTransportObserver.ConnectionObservation	Observation of one physical connection.
static enum	HttpTransportObserver.ConnectionOutcome	Connection termination outcome.
static enum	HttpTransportObserver.Direction	Stream directionality.
static enum	HttpTransportObserver.Handshake	Connection handshake.
static interface	HttpTransportObserver.HandshakeObservation	Observation of one security handshake.
static enum	HttpTransportObserver.HandshakeOutcome	Handshake completion outcome.
static enum	HttpTransportObserver.Initiator	Stream initiator relative to the observing endpoint.
static enum	HttpTransportObserver.Role	Endpoint role.
static interface	HttpTransportObserver.StreamObservation	Observation of one application request and response exchange.
static enum	HttpTransportObserver.StreamOutcome	Stream termination outcome.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	PROTOCOL_HTTP_1_1	Known protocol identifier for HTTP/1.1, aligned with the HTTP transport metrics tag value.
static final String	PROTOCOL_HTTP_2	Known protocol identifier for HTTP/2, aligned with the HTTP transport metrics tag value.
static final String	PROTOCOL_HTTP_3	Known protocol identifier for HTTP/3, aligned with the HTTP transport metrics tag value.
static final String	TRANSPORT_QUIC	Known transport identifier for QUIC.
static final String	TRANSPORT_TCP	Known transport identifier for TCP.
static final String	TRANSPORT_UNIX	Known transport identifier for Unix domain sockets.

Method Summary

Modifier and Type	Method	Description
static HttpTransportObserver	compose(List<? extends HttpTransportObserver> observers)	Combines observers into one failure-isolating observer.
HttpTransportObserver.ConnectionObservation	connectionOpened(HttpTransportObserver.Role role, String transport, HttpTransportObserver.Handshake handshake)	Observes an opened physical connection.
static HttpTransportObserver	noop()	Returns an observer which ignores all lifecycle events.

Field Details

TRANSPORT_TCP

static final String TRANSPORT_TCP

Known transport identifier for TCP.

See Also:

• Constant Field Values

TRANSPORT_UNIX

static final String TRANSPORT_UNIX

Known transport identifier for Unix domain sockets.

See Also:

• Constant Field Values

TRANSPORT_QUIC

static final String TRANSPORT_QUIC

Known transport identifier for QUIC.

See Also:

• Constant Field Values

PROTOCOL_HTTP_1_1

static final String PROTOCOL_HTTP_1_1

Known protocol identifier for HTTP/1.1, aligned with the HTTP transport metrics tag value.

See Also:

• Constant Field Values

PROTOCOL_HTTP_2

static final String PROTOCOL_HTTP_2

Known protocol identifier for HTTP/2, aligned with the HTTP transport metrics tag value.

See Also:

• Constant Field Values

PROTOCOL_HTTP_3

static final String PROTOCOL_HTTP_3

Known protocol identifier for HTTP/3, aligned with the HTTP transport metrics tag value.

See Also:

• Constant Field Values

Method Details

noop

static HttpTransportObserver noop()

Returns an observer which ignores all lifecycle events.

Returns:

no-op observer

compose

static HttpTransportObserver compose(List<? extends HttpTransportObserver> observers)

Combines observers into one failure-isolating observer.

Duplicate observer instances are included only once. A RuntimeException from one observer is logged and does not prevent the remaining observers from receiving the event. Any other Throwable is rethrown; a connection transition failure is rethrown after transitions already queued for that connection complete.

Parameters:

observers - observers to combine

Returns:

combined observer

connectionOpened

HttpTransportObserver.ConnectionObservation connectionOpened(HttpTransportObserver.Role role,
 String transport,
 HttpTransportObserver.Handshake handshake)

Observes an opened physical connection.

The caller owns the returned observation and closes it when the connection terminates. The returned observation must not be null.

Parameters:

role - endpoint role

transport - non-blank physical transport identifier

handshake - connection handshake type

Returns:

connection observation