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.

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

import com.pubnub.api.PubNubException;
import com.pubnub.api.java.PubNub;
import com.pubnub.api.java.v2.PNConfiguration;
import com.pubnub.api.UserId;
import com.pubnub.api.enums.PNLogVerbosity;
import com.pubnub.api.models.consumer.presence.PNHereNowChannelData;
import com.pubnub.api.models.consumer.presence.PNHereNowOccupantData;

import java.util.Arrays;

public class HereNowApp {
    public static void main(String[] args) throws PubNubException {
        // Configure PubNub instance
        PNConfiguration.Builder configBuilder = PNConfiguration.builder(new UserId("demoUserId"), "demo");
        configBuilder.publishKey("demo");
show all 44 lines

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.

pubnub.hereNow()
    .channels(Arrays.asList("my_channel")) // who is present on those channels?
    .includeState(true) // include state with request (false by default)
    .includeUUIDs(true) // if false, only shows occupancy count
    .async(result -> { /* check result */ });

Example Response

.async(result -> {
    result.onSuccess(res -> {
        // Iterate through channels if the request was successful
        for (PNHereNowChannelData channelData : res.getChannels().values()) {
            System.out.println("Channel: " + channelData.getChannelName());
            System.out.println("Occupancy: " + channelData.getOccupancy());
            System.out.println("Occupants:");
            for (PNHereNowOccupantData occupant : channelData.getOccupants()) {
                System.out.println("UUID: " + occupant.getUuid() + " State: " + occupant.getState());
            }
        }
    }).onFailure((PubNubException exception) -> {
        // Handle errors if the request fails
        System.err.println("Error retrieving hereNow data: " + exception.getMessage());
        exception.getPubnubError();
show all 19 lines

Return Occupancy Only

Requires Presence

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

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

pubnub.hereNow()
    .channels(Arrays.asList("my_channel")) // who is present on those channels?
    .includeState(false) // include state with request (false by default)
    .includeUUIDs(false) // if false, only shows occupancy count
    .async(result -> { /* check result */ });

Example Response

.async(result -> {
    result.onSuccess(res -> {
        // Iterate through channels if the request was successful
        for (PNHereNowChannelData channelData : res.getChannels().values()) {
            System.out.println("Channel: " + channelData.getChannelName()); // my_channel
            System.out.println("Occupancy: " + channelData.getOccupancy()); // 3
        }
    }).onFailure((PubNubException exception) -> {
        // Handle errors if the request fails
        System.err.println("Error retrieving hereNow data: " + exception.getMessage());
        exception.getPubnubError();
        exception.getCause();
        exception.getStatusCode();
    });
});

Here Now for Channel Groups

pubnub.hereNow()
    .channelGroups(Arrays.asList("cg1", "cg2", "cg3")) // who is present on channel groups?
    .includeState(true) // include state with request (false by default)
    .includeUUIDs(true) // if false, only shows occupancy count
    .async(result -> { /* check result */ });

Example Response

.async(result -> {
    result.onSuccess(res -> {
        // Get total occupancy across all channels if the request was successful
        System.out.println("Total Occupancy: " + res.getTotalOccupancy()); // 12
        
        // Iterate through channels in the channel group
        for (PNHereNowChannelData channelData : res.getChannels().values()) {
            System.out.println("Channel: " + channelData.getChannelName());
            System.out.println("Occupancy: " + channelData.getOccupancy());
            System.out.println("Occupants:");
            for (PNHereNowOccupantData occupant : channelData.getOccupants()) {
                System.out.println("UUID: " + occupant.getUuid() + " State: " + occupant.getState());
            }
        }
    }).onFailure((PubNubException exception) -> {
show all 22 lines

Where Now

Requires Presence

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

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

pubnub.whereNow()
    .async(result -> { /* check result */ });

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

pubnub.whereNow()
    .uuid("some-other-uuid") // uuid of the user we want to spy on.
    .async(result -> { /* check result */ });

User State

Requires Presence

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

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

JsonObject state = new JsonObject();
state.addProperty("is_typing", isTyping);

pubnub.setPresenceState()
    .channels(Arrays.asList(channel))
    .state(state)
    .async(result -> { /* check result */ });

Get State

pubnub.getPresenceState()
    .channels(Arrays.asList("ch1", "ch2", "ch3")) // channels to fetch state for
    .channelGroups(Arrays.asList("cg1", "cg2", "cg3")) // channel groups to fetch state for
    .uuid("suchUUID") // uuid of user to fetch, or for own uuid
    .async(result -> { /* check result */ });

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

JsonObject state = new JsonObject();
state.addProperty("is_typing", isTyping);

pubnub.setPresenceState()
    .channelGroups(Arrays.asList("cg1", "cg2", "cg3")) // apply on those channel groups
    .channels(Arrays.asList("ch1", "ch2", "ch3")) // apply on those channels
    .state(state) // the new state
    .async(result -> { /* check result */ });

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

if (presence.getEvent().equals("state-change")) {
        boolean is_typing = presence.getState()
                            .getAsJsonObject()
                            .get("is_typing")
                            .getAsBoolean();
    }

Breaking changes in v9.0.0

Here Now​

Requires Presence

Cache

Method(s)​

Basic Usage​

Reference code

Get a list of UUIDs subscribed to channel​

Returns​

PNHereNowChannelData​

PNHereNowOccupantData​

Other Examples​

Returning State​

Requires Presence

Example Response​

Return Occupancy Only​

Requires Presence

Example Response​

Here Now for Channel Groups​

Example Response​

Where Now​

Requires Presence

Timeout events

Method(s)​

Basic Usage​

Get a list of channels a UUID is subscribed to​

Returns​

Other Examples​

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

User State​

Requires Presence

Presence state format

Method(s)​

Set State​

Get State​

Basic Usage​

Set State​

Get State​

Returns​

Other Examples​

Set state for channels in channel group​

Here Now

Method(s)

Basic Usage

Get a list of UUIDs subscribed to channel

Returns

PNHereNowChannelData

PNHereNowOccupantData

Other Examples

Returning State

Example Response

Return Occupancy Only

Example Response

Here Now for Channel Groups

Example Response

Where Now

Method(s)

Basic Usage

Get a list of channels a UUID is subscribed to

Returns

Other Examples

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

User State

Method(s)

Set State

Get State

Basic Usage

Set State

Get State

Returns

Other Examples

Set state for channels in channel group