software.amazon.smithy.mqtt.traits

Class TopicBinding<T extends Trait>

java.lang.Object

software.amazon.smithy.mqtt.traits.TopicBinding<T>

public final class TopicBinding<T extends Trait>
extends java.lang.Object

Contains computed information about the resolved MQTT topic bindings of an operation.

Smithy models can contain a number of MQTT topics that are formed by the publish and subscribe traits. Each of these traits resolves to a single MQTT topic.

This class abstracts away the process of computing the payload of an MQTT operation. Each topic binding provides the following information:

• The operation in the model that created the binding.
• The MQTT topic.
• The payload shape that forms the payload of the topic.
• The optionally present input structure of the operation, which provides information like topic label bindings.

@smithy.mqtt#publish topics

Operations marked with @smithy.mqtt#publish resolve to a single topic that is defined by topic property of the trait.

subscribe topics

Operations marked with subscribe resolve to a single topic that is defined by the topic property of the trait.

Payload resolution

The payload binding of a topic binding can be resolved to either no payload (e.g., publish operations with no input shape), a structure payload, or a member of a structure. The target of a specific event shape member can be used as a payload in subscribe operations where an event member is marked with the eventPayload trait.

Method Summary

Modifier and Type	Method and Description
boolean	conflictsWith(TopicBinding<?> other) Returns true if the topic binding conflicts with another.
boolean	equals(java.lang.Object o)
java.util.Optional<StructureShape>	getInput() Deprecated. Use getInputShape instead.
StructureShape	getInputShape() Gets the input shape related to this operation.
T	getMqttTrait() Gets the trait that formed the binding of the operation to MQTT for this topic.
OperationShape	getOperation() Gets the operation shape related to the topic bindings.
static java.util.Optional<? extends Trait>	getOperationMqttTrait(Shape operation) Finds the MQTT binding trait associated with an operation.
java.util.Optional<Shape>	getPayloadShape() Gets the payload shape of the topic.
Topic	getTopic() Gets the resolved topic of the binding.
int	hashCode()
java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Method Detail

getOperationMqttTrait

public static java.util.Optional<? extends Trait> getOperationMqttTrait(Shape operation)

Finds the MQTT binding trait associated with an operation.

Parameters:

operation - Operation to check.

Returns:

Returns the optionally found MQTT binding trait.

getMqttTrait

public T getMqttTrait()

Gets the trait that formed the binding of the operation to MQTT for this topic.

The provided trait will be either an instance of PublishTrait or SubscribeTrait.

Returns:

Returns the MQTT trait binding.

getOperation

public OperationShape getOperation()

Gets the operation shape related to the topic bindings.

Returns:

Returns the operation that has topic bindings.

getTopic

public Topic getTopic()

Gets the resolved topic of the binding.

Returns:

Returns the resolved topic.

getInput

@Deprecated
public java.util.Optional<StructureShape> getInput()

Deprecated. Use getInputShape instead.

Gets the input shape related to this operation.

Returns:

Returns the optional input shape.

getInputShape

public StructureShape getInputShape()

Gets the input shape related to this operation.

Returns:

Returns the input shape.

getPayloadShape

public java.util.Optional<Shape> getPayloadShape()

Gets the payload shape of the topic.

The payload shape is either a structure for a single-event event stream, or a union for a multi-event event stream.

Returns:

Returns the optional payload target.

conflictsWith

public boolean conflictsWith(TopicBinding<?> other)

Returns true if the topic binding conflicts with another.

A topic binding is considered conflicting if both bindings have conflicting topics determined through Topic.conflictsWith(software.amazon.smithy.mqtt.traits.Topic) and the topic bindings utilize a different payload. If both topics do not have a payload then they are not conflicting. If both topics have a payload, but they target the same shape, then they are not conflicting.

Parameters:

other - Other topic binding to compare against.

Returns:

Returns true if the topic bindings conflict.

equals

public boolean equals(java.lang.Object o)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object