Querier class

A zenoh querier for efficiently sending multiple queries on a single key expression with pre-configured options.

Wraps z_owned_querier_t. Call close when done to undeclare the querier and release native resources.

This object holds a native handle, so it cannot cross an isolate boundary: a copy would share this one's native address while carrying its own fresh disposal flag, and the second release would be a use-after-free. Sending it throws ArgumentError naming the class.

⛔ No NativeFinalizer is attached to this class, deliberately: a get() hands the caller a Stream<Reply> whose listener captures the port and controller, NOT the querier — so the querier is unreferenced while its query is in flight, and releasing it there terminates the get with zero replies. Releasing it explicitly is therefore the only thing that reclaims it.

Implemented types

• Finalizable

Constructors

Querier.declare(Pointer<Void> loanedSession, Pointer<Void> loanedKeyExpr, String keyExpr, {QueryTarget target = QueryTarget.bestMatching, ConsolidationMode consolidation = ConsolidationMode.auto, Duration? timeout, CongestionControl? congestionControl, Priority? priority, bool? isExpress, Locality? allowedDestination, ReplyKeyExpr? acceptReplies, bool enableMatchingListener = false})

Creates a querier on the given session and key expression.

factory

Properties

hashCode → int

The hash code for this object.

no setter, inherited

keyExpr → String

The key expression this querier is declared on.

no setter

matchingStatus → Stream<bool>?

A stream of matching status changes, or null if the matching listener was not enabled when the querier was declared. ⚠️ Unbounded, like every push stream here — but this is an edge-signal channel, not a data channel: it carries transitions, not traffic, so there is deliberately no bounded form of it.

no setter

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

close() → void

Undeclares the querier and releases native resources.

get({String? parameters, ZBytes? payload, Encoding? encoding, ZBytes? attachment, bool retainPayload = false}) → Stream<Reply>

Sends a query via this querier and returns a stream of replies.

hasMatchingQueryables() → bool

Returns whether any queryables currently match this querier's key expression.

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

pullGet({required ChannelKind kind, required int capacity, String? parameters, ZBytes? payload, Encoding? encoding, ZBytes? attachment, bool retainPayload = false}) → PullReplies

Sends a query via this querier, with replies landing in a bounded channel instead of a stream.

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited