edu.wpi.rail.jrosbridge

Class Topic

java.lang.Object

edu.wpi.rail.jrosbridge.Topic

public class Topic
extends Object

The Topic object is responsible for publishing and/or subscribing to a topic in ROS.

Version:

April 1, 2014

Author:

Russell Toris - rctoris@wpi.edu

Constructor Summary

Constructors

Constructor and Description
Topic(Ros ros, String name, String type) Create a ROS topic with the given information.
Topic(Ros ros, String name, String type, int throttleRate) Create a ROS topic with the given information.
Topic(Ros ros, String name, String type, JRosbridge.CompressionType compression) Create a ROS topic with the given information.
Topic(Ros ros, String name, String type, JRosbridge.CompressionType compression, int throttleRate) Create a ROS topic with the given information.

Method Summary

Methods

Modifier and Type	Method and Description
void	advertise() Registers as a publisher for the topic.
JRosbridge.CompressionType	getCompression() Get the compression type for this topic.
String	getName() Get the name of this topic.
Ros	getRos() Get the ROS connection handle for this topic.
int	getThrottleRate() Get the throttle rate for this topic.
String	getType() Return the message type of this topic.
boolean	isAdvertised() Check if the current topic is advertising to ROS.
boolean	isSubscribed() Check if the current topic is subscribed to ROS.
void	publish(Message message) Publish the given message to ROS on this topic.
void	subscribe(TopicCallback cb) Subscribe to this topic.
void	unadvertise() Unregister as a publisher for the topic.
void	unsubscribe() Unregisters as a subscriber for the topic.

Methods inherited from class java.lang.Object

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

Constructor Detail

Topic

public Topic(Ros ros,
     String name,
     String type)

Create a ROS topic with the given information. No compression or throttling is used.

Parameters:

ros - A handle to the ROS connection.

name - The name of the topic (e.g., "/cmd_vel").

type - The message type (e.g., "std_msgs/String").

Topic

public Topic(Ros ros,
     String name,
     String type,
     JRosbridge.CompressionType compression)

Create a ROS topic with the given information. No throttling is used.

Parameters:

ros - A handle to the ROS connection.

name - The name of the topic (e.g., "/cmd_vel").

type - The message type (e.g., "std_msgs/String").

compression - The type of compression used for this topic.

Topic

public Topic(Ros ros,
     String name,
     String type,
     int throttleRate)

Create a ROS topic with the given information. No compression is used.

Parameters:

ros - A handle to the ROS connection.

name - The name of the topic (e.g., "/cmd_vel").

type - The message type (e.g., "std_msgs/String").

throttleRate - The throttle rate to use for this topic.

Topic

public Topic(Ros ros,
     String name,
     String type,
     JRosbridge.CompressionType compression,
     int throttleRate)

Create a ROS topic with the given information.

Parameters:

ros - A handle to the ROS connection.

name - The name of the topic (e.g., "/cmd_vel").

type - The message type (e.g., "std_msgs/String").

compression - The type of compression used for this topic.

throttleRate - The throttle rate to use for this topic.

Method Detail

getRos

public Ros getRos()

Get the ROS connection handle for this topic.

Returns:

The ROS connection handle for this topic.

getName

public String getName()

Get the name of this topic.

Returns:

The name of this topic.

getType

public String getType()

Return the message type of this topic.

Returns:

The message type of this topic.

isAdvertised

public boolean isAdvertised()

Check if the current topic is advertising to ROS.

Returns:

If the current topic is advertising to ROS.

isSubscribed

public boolean isSubscribed()

Check if the current topic is subscribed to ROS.

Returns:

If the current topic is subscribed to ROS.

getCompression

public JRosbridge.CompressionType getCompression()

Get the compression type for this topic.

Returns:

The compression type for this topic.

getThrottleRate

public int getThrottleRate()

Get the throttle rate for this topic.

Returns:

The throttle rate for this topic.

subscribe

public void subscribe(TopicCallback cb)

Subscribe to this topic. A callback function is required and will be called with any incoming message for this topic.

Parameters:

cb - The callback that will be called when incoming messages are received.

unsubscribe

public void unsubscribe()

Unregisters as a subscriber for the topic. Unsubscribing will remove all the associated subscribe callbacks.

advertise

public void advertise()

Registers as a publisher for the topic. This call will be automatically called by publish if you do not explicitly call it.

unadvertise

public void unadvertise()

Unregister as a publisher for the topic.

publish

public void publish(Message message)

Publish the given message to ROS on this topic. If the topic is not advertised, it will be advertised first.

Parameters:

message - The message to publish.