Package edu.wpi.first.networktables

Class StructTopic<T>

java.lang.Object

edu.wpi.first.networktables.Topic

edu.wpi.first.networktables.StructTopic<T>

Type Parameters:

T - value class

public final class StructTopic<T>
extends Topic

NetworkTables struct-encoded value topic.

Field Summary

Fields inherited from class edu.wpi.first.networktables.Topic

m_handle, m_inst

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object other)
StructEntry<T>	getEntry(T defaultValue, PubSubOption... options)	Create a new entry for the topic.
Struct<T>	getStruct()	Returns the struct.
int	hashCode()
StructPublisher<T>	publish(PubSubOption... options)	Create a new publisher to the topic.
StructPublisher<T>	publishEx(String properties, PubSubOption... options)	Create a new publisher to the topic, with type string and initial properties.
StructSubscriber<T>	subscribe(T defaultValue, PubSubOption... options)	Create a new subscriber to the topic.
static <T> StructTopic<T>	wrap(NetworkTableInstance inst, int handle, Struct<T> struct)	Create a StructTopic from a native handle; generally NetworkTableInstance.getStructTopic() should be used instead.
static <T> StructTopic<T>	wrap(Topic topic, Struct<T> struct)	Create a StructTopic from a generic topic.

Methods inherited from class edu.wpi.first.networktables.Topic

deleteProperty, exists, genericPublish, genericPublishEx, genericSubscribe, genericSubscribe, getGenericEntry, getGenericEntry, getHandle, getInfo, getInstance, getName, getProperties, getProperty, getType, getTypeString, isCached, isPersistent, isRetained, isValid, setCached, setPersistent, setProperties, setProperty, setRetained

Methods inherited from class java.lang.Object

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

Method Details

wrap

public static <T> StructTopic<T> wrap(Topic topic, Struct<T> struct)

Create a StructTopic from a generic topic.

Type Parameters:

T - value class (inferred from struct)

Parameters:

topic - generic topic

struct - struct serialization implementation

Returns:

StructTopic for value class

wrap

public static <T> StructTopic<T> wrap(NetworkTableInstance inst, int handle, Struct<T> struct)

Create a StructTopic from a native handle; generally NetworkTableInstance.getStructTopic() should be used instead.

Type Parameters:

T - value class (inferred from struct)

Parameters:

inst - Instance

handle - Native handle

struct - struct serialization implementation

Returns:

StructTopic for value class

subscribe

public StructSubscriber<T> subscribe(T defaultValue, PubSubOption... options)

Create a new subscriber to the topic.

The subscriber is only active as long as the returned object is not closed.

Subscribers that do not match the published data type do not return any values. To determine if the data type matches, use the appropriate Topic functions.

Parameters:

defaultValue - default value used when a default is not provided to a getter function

options - subscribe options

Returns:

subscriber

publish

public StructPublisher<T> publish(PubSubOption... options)

Create a new publisher to the topic.

The publisher is only active as long as the returned object is not closed.

It is not possible to publish two different data types to the same topic. Conflicts between publishers are typically resolved by the server on a first-come, first-served basis. Any published values that do not match the topic's data type are dropped (ignored). To determine if the data type matches, use the appropriate Topic functions.

Parameters:

options - publish options

Returns:

publisher

publishEx

public StructPublisher<T> publishEx(String properties, PubSubOption... options)

Create a new publisher to the topic, with type string and initial properties.

The publisher is only active as long as the returned object is not closed.

It is not possible to publish two different data types to the same topic. Conflicts between publishers are typically resolved by the server on a first-come, first-served basis. Any published values that do not match the topic's data type are dropped (ignored). To determine if the data type matches, use the appropriate Topic functions.

Parameters:

properties - JSON properties

options - publish options

Returns:

publisher

Throws:

IllegalArgumentException - if properties is not a JSON object

getEntry

public StructEntry<T> getEntry(T defaultValue, PubSubOption... options)

Create a new entry for the topic.

Entries act as a combination of a subscriber and a weak publisher. The subscriber is active as long as the entry is not closed. The publisher is created when the entry is first written to, and remains active until either unpublish() is called or the entry is closed.

It is not possible to use two different data types with the same topic. Conflicts between publishers are typically resolved by the server on a first-come, first-served basis. Any published values that do not match the topic's data type are dropped (ignored), and the entry will show no new values if the data type does not match. To determine if the data type matches, use the appropriate Topic functions.

Parameters:

defaultValue - default value used when a default is not provided to a getter function

options - publish and/or subscribe options

Returns:

entry

getStruct

public Struct<T> getStruct()

Returns the struct.

Returns:

The struct.

equals

public boolean equals(Object other)

Overrides:

equals in class Topic

hashCode

public int hashCode()

Overrides:

hashCode in class Topic