Presence API for Java SDK

Breaking changes in v9.0.0

PubNub Java SDK version 9.0.0 unifies the codebases for Java and Kotlin SDKs, introduces a new way of instantiating the PubNub client, and changes asynchronous API callbacks and emitted status events. These changes can impact applications built with previous versions (< 9.0.0) of the Java SDK.

For more details about what has changed, refer to Java/Kotlin SDK migration guide.

Presence enables you to track the online and offline status of users and devices in real time, and store custom state information. Presence provides authoritative information on:

• When a user has joined or left a channel
• Who, and how many, users are subscribed to a particular channel
• Which channel(s) an individual user is subscribed to
• Associated state information for these users

Learn more about our Presence feature here.

Here Now

Requires Presence

This method requires that the Presence add-on is enabled for your key in the Admin Portal.

For information on how to receive presence events and what those events are, refer to Presence Events.

You can obtain information about the current state of a channel including a list of unique user-ids currently subscribed to the channel and the total occupancy count of the channel by calling the hereNow() function in your application.

Cache

This method has a 3 second response cache time.

Method(s)

To call Here Now you can use the following method(s) in the Java SDK:

this.pubnub.hereNow()
    .channels(Array)
    .channelGroups(Arrays)
    .includeState(true)
    .includeUUIDs(true)

* required

Parameter	Description
channels Type: Array Default: n/a	The channels to get the here now details.
channelGroups Type: Arrays Default: n/a	The channelGroups to get the here now details.
includeState Type: Boolean Default: false	If true, the response will include the presence states of the users for channels/channelGroups
includeUUIDs Type: Boolean Default: true	If true, the response will include the UUIDs of the connected clients.
async * Type: Consumer<Result> Default: n/a	Consumer of a Result of type PNHereNowResult

Basic Usage

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

Get a list of UUIDs subscribed to channel

Returns

The hereNow() operation returns a PNHereNowResult which contains the following operations:

Method	Description
getTotalChannels() Type: Int	Total Channels.
getTotalOccupancy() Type: Int	Total Occupancy.
getChannels() Type: Map<String, PNHereNowChannelData>	A map with values of PNHereNowChannelData for each channel. See PNHereNowChannelData for more details.

PNHereNowChannelData

Method	Description
getChannelName() Type: String	Channel name.
getOccupancy() Type: Int	Occupancy of the channel.
getOccupants() Type: List<PNHereNowOccupantData>	A list of PNHereNowOccupantData, see PNHereNowOccupantData for more details.

PNHereNowOccupantData

Method	Description
getUuid() Type: String	UUIDs of the user.
getState() Type: Object	State of the user.

Other Examples

Returning State

Requires Presence

This method requires that the Presence add-on is enabled for your key in the Admin Portal.

For information on how to receive presence events and what those events are, refer to Presence Events.

Return Occupancy Only

Requires Presence

This method requires that the Presence add-on is enabled for your key in the Admin Portal.

For information on how to receive presence events and what those events are, refer to Presence Events.

You can return only the occupancy information for a single channel by specifying the channel and setting UUIDs to false:

Here Now for Channel Groups

Where Now

Requires Presence

This method requires that the Presence add-on is enabled for your key in the Admin Portal.

For information on how to receive presence events and what those events are, refer to Presence Events.

You can obtain information about the current list of channels to which a UUID is subscribed to by calling the whereNow() function in your application.

Timeout events

If the app is killed/crashes and restarted (or the page containing the PubNub instance is refreshed on the browser) within the heartbeat window no timeout event is generated.

Method(s)

To call whereNow() you can use the following method(s) in the Java SDK:

pubnub.whereNow()
    .uuid(String)

* required

Parameter	Description
uuid Type: String	Uuid of the user we want to spy on.
async * Type: Command	Execute as async.

Basic Usage

You simply need to define the uuid and the callback function to be used to send the data to as in the example below.

Get a list of channels a UUID is subscribed to

Returns

The whereNow() operation returns a PNWhereNowResult which contains the following operations:

Method	Description
getChannels() Type: List<String>	The list of channels where the UUID is present.

Other Examples

Obtain information about the current list of channels of some other UUID

User State

Requires Presence

This method requires that the Presence add-on is enabled for your key in the Admin Portal.

For information on how to receive presence events and what those events are, refer to Presence Events.

Clients can set a dynamic custom state (score, game state, location) for their users on one or more channels and store it on a channel as long as the user stays subscribed.

The state is not persisted, and when the client disconnects, the state data is lost. For more information, refer to Presence State.

Presence state format

Presence state must be expressed as a JsonObject. When calling setState, be sure to supply an initialized JsonObject or POJO which can be serialized to a JsonObject.

Method(s)

Set State

this.pubnub.setPresenceState()
    .channels(Array)
    .channelGroups(Array)
    .state(HashMap)
    .uuid(String)

* required

Parameter	Description
channels Type: Array	Channels to set state.
channelGroups Type: Array	ChannelGroups to set state.
state Type: HashMap	State to set.
uuid Type: String	Set state for specific UUID.
async * Type: Consumer<Result>	Consumer of a Result of type PNSetStateResult.

Get State

this.pubnub.getPresenceState()
    .channels(Arrays)
    .channelGroups(Arrays)
    .uuid(String)

* required

Parameter	Description
channels Type: Arrays	Channel name to fetch the state.
channelGroups Type: Arrays	ChannelGroups name to fetch the state.
uuid Type: String	UUID
async * Type: Consumer<Result>	Consumer of a Result of type PNGetStateResult.

Basic Usage

Set State

Get State

Returns

The setPresenceState() operation returns a PNSetStateResult which contains the following operations:

Method	Description
getState() Type: Map<String, Object>	Map of UUIDs and the user states.

The getPresenceState() operation returns a PNGetStateResult which contains the following operations:

Method	Description
getStateByUUID() Type: Map<String, Object>	Map of UUIDs and the user states.

Other Examples

Set state for channels in channel group

The above code would return the following response to the client: