Multi User Chat =============== [Back](index.md) Allows configuration of, participation in, and administration of individual text-based conference rooms. * Create a new Room * Join a room * Manage room invitations * Discover MUC support * Discover joined rooms * Discover room information * Start a private chat * Manage changes on room subject * Manage role modifications * Manage affiliation modifications **XEP related:** [XEP-45](http://www.xmpp.org/extensions/xep-0045.html) For all examples in this document, assume that the following variables exists: ```java // Create the XMPP address (JID) of the MUC. EntityBareJid mucJid = JidCreate.bareFrom("myroom@conference.jabber.org"); // Create the nickname. Resourcepart nickname = Resourcepart.from("testbot"); // A other use (we may invite him to a MUC). FullJid otherJid = JidCreate.fullFrom("user3@host.org/Smack"); ``` Create a new Room ----------------- **Description** Allowed users may create new rooms. There are two types of rooms that you can create. **Instant rooms** which are available for immediate access and are automatically created based on some default configuration and **Reserved rooms** which are manually configured by the room creator before anyone is allowed to enter. **Usage** In order to create a room you will need to first create an instance of _**MultiUserChat**_. In order to do so, get a instance of `MultiUserChatManager` and call `getMultiUserChat(String)` to retrieve a `MultiUserChat` instance. The next step is to send **create(String nickname)** to the _**MultiUserChat**_ instance where nickname is the nickname to use when joining the room. Depending on the type of room that you want to create you will have to use different configuration forms. In order to create an Instant room just use `MucCreateConfigFormHandle.makeInstant()`. But if you want to create a Reserved room then you should first get the room's configuration form, complete the form and finally send it back to the server. **Examples** In this example we can see how to create an instant room: ```java // Get the MultiUserChatManager MultiUserChatManager manager = MultiUserChatManager.getInstanceFor(connection); // Get a MultiUserChat using MultiUserChatManager MultiUserChat muc = manager.getMultiUserChat(mucJid); // Create the room and send an empty configuration form to make this an instant room muc.create(nickname).makeInstant(); ``` In this example we can see how to create a reserved room. The form is completed with default values: ```java // Get the MultiUserChatManager MultiUserChatManager manager = MultiUserChatManager.getInstanceFor(connection); // Create a MultiUserChat using an XMPPConnection for a room MultiUserChat muc = = manager.getMultiUserChat(mucJid); // Prepare a list of owners of the new room Set owners = JidUtil.jidSetFrom(new String[] { "me@example.org", "juliet@example.org" }); // Create the room muc.create(nickname) .getConfigFormManger() .setRoomOwners(owners) .submitConfigurationForm(); ``` Join a room ----------- **Description** Your usual first step in order to send messages to a room is to join the room. Multi User Chat allows to specify several parameter while joining a room. Basically you can control the amount of history to receive after joining the room as well as provide your nickname within the room and a password if the room is password protected. **Usage** In order to join a room you will need to first get an instance of _**MultiUserChat**_. In order to do so, get a instance of `MultiUserChatManager` and call `getMultiUserChat(String)` to retrieve a `MultiUserChat` instance. The next step is to send **join(...)** to the _**MultiUserChat**_ instance. But first you will have to decide which join message to send. If you want to just join the room without a password and without specifying the amount of history to receive then you could use **join(String nickname)** where nickname if your nickname in the room. In case the room requires a password in order to join you could then use **join(String nickname, String password)**. And finally, the most complete way to join a room is to send **join(String nickname, String password, DiscussionHistory history, long timeout)** where nickname is your nickname in the room, , password is your password to join the room, history is an object that specifies the amount of history to receive and timeout is the milliseconds to wait for a response from the server. **Examples** In this example we can see how to join a room with a given nickname: ```java // Get the MultiUserChatManager MultiUserChatManager manager = MultiUserChatManager.getInstanceFor(connection); // Create a MultiUserChat using an XMPPConnection for a room MultiUserChat muc2 = manager.getMultiUserChat(mucJid); // User2 joins the new room // The room service will decide the amount of history to send muc2.join(nickname); ``` In this example we can see how to join a room with a given nickname and password: ```java // Get the MultiUserChatManager MultiUserChatManager manager = MultiUserChatManager.getInstanceFor(connection); // Create a MultiUserChat using an XMPPConnection for a room MultiUserChat muc2 = manager.getMultiUserChat(mucJid); // User2 joins the new room using a password // The room service will decide the amount of history to send muc2.join(nickname, "password"); ``` In this example we can see how to join a room with a given nickname specifying the amount of history to receive: ```java // Get the MultiUserChatManager MultiUserChatManager manager = MultiUserChatManager.getInstanceFor(connection); // Create a MultiUserChat using an XMPPConnection for a room MultiUserChat muc2 = manager.getMultiUserChat(mucJid); // User2 joins the new room using a password and specifying // the amount of history to receive. In this example we are requesting the last 5 messages. DiscussionHistory history = new DiscussionHistory(); history.setMaxStanzas(5); muc2.join(nickname, "password", history, conn1.getPacketReplyTimeout()); ``` Manage room invitations ----------------------- **Description** It can be useful to invite another user to a room in which one is an occupant. Depending on the room's type the invitee could receive a password to use to join the room and/or be added to the member list if the room is of type members-only. Smack allows to send room invitations and let potential invitees to listening for room invitations and inviters to listen for invitees' rejections. **Usage** In order to invite another user to a room you must be already joined to the room. Once you are joined just send **invite(String participant, String reason)** to the _**MultiUserChat**_ where participant is the user to invite to the room (e.g. hecate@shakespeare.lit) and reason is the reason why the user is being invited. If potential invitees want to listen for room invitations then the invitee must add an _**InvitationListener**_ to the _**MultiUserChatManager**_ class. Since the _**InvitationListener**_ is an _interface_, it is necessary to create a class that implements this _interface_. If an inviter wants to listen for room invitation rejections, just add an _**InvitationRejectionListener**_ to the _**MultiUserChat**_. _**InvitationRejectionListener**_ is also an interface so you will need to create a class that implements this interface. **Examples** In this example we can see how to invite another user to the room and lister for possible rejections: ```java // Get the MultiUserChatManager MultiUserChatManager manager = MultiUserChatManager.getInstanceFor(connection); // Create a MultiUserChat using an XMPPConnection for a room MultiUserChat muc2 = manager.getMultiUserChat(mucJid); muc2.join(nickname); // User2 listens for invitation rejections muc2.addInvitationRejectionListener(new InvitationRejectionListener() { public void invitationDeclined(String invitee, String reason) { // Do whatever you need here... } }); // User2 invites user3 to join to the room muc2.invite(otherJid, "Meet me in this excellent room"); ``` In this example we can see how to listen for room invitations and decline invitations: ```java // User3 listens for MUC invitations MultiUserChatManager.getInstanceFor(connection).addInvitationListener(new InvitationListener() { public void invitationReceived(XMPPConnection conn, String room, EntityFullJid inviter, String reason, String password) { // Reject the invitation MultiUserChat.decline(conn, room, inviter.asBareJid()s, "I'm busy right now"); } }); ``` Discover MUC support -------------------- **Description** A user may want to discover if one of the user's contacts supports the Multi- User Chat protocol. **Usage** In order to discover if one of the user's contacts supports MUC just send **isServiceEnabled(String user)** to the _**MultiUserChatManager**_ class where user is a fully qualified XMPP ID, e.g. jdoe@example.com. You will receive a boolean indicating whether the user supports MUC or not. **Examples** In this example we can see how to discover support of MUC: ```java // Discover whether user3@host.org supports MUC or not boolean supports = MultiUserChatManager.getInstanceFor(connection).isServiceEnabled(otherJid); ``` Discover joined rooms --------------------- **Description** A user may also want to query a contact regarding which rooms the contact is in. **Usage** In order to get the rooms where a user is in just send **getJoinedRooms(String user)** to the _**MultiUserChatManager**_ class where user is a fully qualified XMPP ID, e.g. jdoe@example.com. You will get an Iterator of Strings as an answer where each String represents a room name. **Examples** In this example we can see how to get the rooms where a user is in: ```java // Get the MultiUserChatManager MultiUserChatManager manager = MultiUserChatManager.getInstanceFor(connection); // Get the rooms where user3@host.org has joined List joinedRooms = manager.getJoinedRooms("user3@host.org/Smack"); ``` Discover room information ------------------------- **Description** A user may need to discover information about a room without having to actually join the room. The server will provide information only for public rooms. **Usage** In order to discover information about a room just send **getRoomInfo(String room)** to the _**MultiUserChatManager**_ class where room is the XMPP ID of the room, e.g. roomName@conference.myserver. You will get a RoomInfo object that contains the discovered room information. **Examples** In this example we can see how to discover information about a room: ```java // Get the MultiUserChatManager MultiUserChatManager manager = MultiUserChatManager.getInstanceFor(connection); // Discover information about the room roomName@conference.myserver RoomInfo info = manager.getRoomInfo("roomName@conference.myserver"); System.out.println("Number of occupants:" + info.getOccupantsCount()); System.out.println("Room Subject:" + info.getSubject()); ``` Start a private chat -------------------- **Description** A room occupant may want to start a private chat with another room occupant even though they don't know the fully qualified XMPP ID (e.g. jdoe@example.com) of each other. **Usage** To create a private chat with another room occupant just send **createPrivateChat(String participant)** to the _**MultiUserChat**_ that you used to join the room. The parameter participant is the occupant unique room JID (e.g. 'darkcave@macbeth.shakespeare.lit/Paul'). You will receive a regular _**Chat**_ object that you can use to chat with the other room occupant. **Examples** In this example we can see how to start a private chat with another room occupant: ``` // Start a private chat with another participant Chat chat = muc2.createPrivateChat("myroom@conference.jabber.org/johndoe"); chat.sendMessage("Hello there"); ``` Manage changes on room subject ------------------------------ **Description** A common feature of multi-user chat rooms is the ability to change the subject within the room. As a default, only users with a role of "moderator" are allowed to change the subject in a room. Although some rooms may be configured to allow a mere participant or even a visitor to change the subject. Every time the room's subject is changed you may want to be notified of the modification. The new subject could be used to display an in-room message. **Usage** In order to modify the room's subject just send **changeSubject(String subject)** to the _**MultiUserChat**_ that you used to join the room where subject is the new room's subject. On the other hand, if you want to be notified whenever the room's subject is modified you should add a _**SubjectUpdatedListener**_ to the _**MultiUserChat**_ by sending **addSubjectUpdatedListener(SubjectUpdatedListener listener)** to the _**MultiUserChat**_. Since the _**SubjectUpdatedListener**_ is an _interface_, it is necessary to create a class that implements this _interface_. **Examples** In this example we can see how to change the room's subject and react whenever the room's subject is modified: ``` // An occupant wants to be notified every time the room's subject is changed muc3.addSubjectUpdatedListener(new SubjectUpdatedListener() { public void subjectUpdated(String subject, String from) { .... } }); // A room's owner changes the room's subject muc2.changeSubject("New Subject"); ``` Manage role modifications ------------------------- **Description** There are four defined roles that an occupant can have: 1. Moderator 2. Participant 3. Visitor 4. None (the absence of a role) These roles are temporary in that they do not persist across a user's visits to the room and can change during the course of an occupant's visit to the room. A moderator is the most powerful occupant within the context of the room, and can to some extent manage other occupants' roles in the room. A participant has fewer privileges than a moderator, although he or she always has the right to speak. A visitor is a more restricted role within the context of a moderated room, since visitors are not allowed to send messages to all occupants. Roles are granted, revoked, and maintained based on the occupant's room nickname or full JID. Whenever an occupant's role is changed Smack will trigger specific events. **Usage** In order to grant voice (i.e. make someone a _participant_) just send the message **grantVoice(String nickname)** to _**MultiUserChat**_. Use **revokeVoice(String nickname)** to revoke the occupant's voice (i.e. make the occupant a _visitor_). In order to grant moderator privileges to a participant or visitor just send the message **grantModerator(String nickname)** to _**MultiUserChat**_. Use **revokeModerator(String nickname)** to revoke the moderator privilege from the occupant thus making the occupant a participant. Smack allows you to listen for role modification events. If you are interested in listening role modification events of any occupant then use the listener **_ParticipantStatusListener_**. But if you are interested in listening for your own role modification events, use the listener **_UserStatusListener_**. Both listeners should be added to the _**MultiUserChat**_ by using **addParticipantStatusListener(ParticipantStatusListener listener)** or **addUserStatusListener(UserStatusListener listener)** respectively. These listeners include several notification events but you may be interested in just a few of them. Smack provides default implementations for these listeners avoiding you to implement all the interfaces' methods. The default implementations are **_DefaultUserStatusListener_** and **_DefaultParticipantStatusListener_**. Below you will find the sent messages to the listeners whenever an occupant's role has changed. These are the triggered events when the role has been upgraded: | Old | New | Events | |-----|-----|--------| | None | Visitor | -- | | Visitor | Participant | voiceGranted | | Participant | Moderator | moderatorGranted | | None | Participant | voiceGranted | | None | Moderator | voiceGranted + moderatorGranted | | Visitor | Moderator | voiceGranted + moderatorGranted | These are the triggered events when the role has been downgraded: | Old | New | Events | |-----|-----|--------| | Moderator | Participant | moderatorRevoked | | Participant | Visitor | voiceRevoked | | Visitor | None | kicked | | Moderator | Visitor | voiceRevoked + moderatorRevoked | | Moderator | None | kicked | | Participant | None | kicked | **Examples** In this example we can see how to grant voice to a visitor and listen for the notification events: ```java // User1 creates a room muc = manager.getMultiUserChat("myroom@conference.jabber.org"); muc.create("testbot"); // User1 (which is the room owner) configures the room as a moderated room Form form = muc.getConfigurationForm(); Form answerForm = form.createAnswerForm(); answerForm.setAnswer("muc#roomconfig_moderatedroom", "1"); muc.sendConfigurationForm(answerForm); // User2 joins the new room (as a visitor) MultiUserChat muc2 = manager2.getMultiUserChat("myroom@conference.jabber.org"); muc2.join("testbot2"); // User2 will listen for his own "voice" notification events muc2.addUserStatusListener(new DefaultUserStatusListener() { public void voiceGranted() { super.voiceGranted(); ... } public void voiceRevoked() { super.voiceRevoked(); ... } }); // User3 joins the new room (as a visitor) MultiUserChat muc3 = manager3.getMultiUserChat("myroom@conference.jabber.org"); muc3.join("testbot3"); // User3 will lister for other occupants "voice" notification events muc3.addParticipantStatusListener(new DefaultParticipantStatusListener() { public void voiceGranted(String participant) { super.voiceGranted(participant); ... } public void voiceRevoked(String participant) { super.voiceRevoked(participant); ... } }); // The room's owner grants voice to user2 muc.grantVoice("testbot2"); ``` Manage affiliation modifications -------------------------------- **Description** There are five defined affiliations that a user can have in relation to a room: 1. Owner 2. Admin 3. Member 4. Outcast 5. None (the absence of an affiliation) These affiliations are semi-permanent in that they persist across a user's visits to the room and are not affected by happenings in the room. Affiliations are granted, revoked, and maintained based on the user's bare JID. If a user without a defined affiliation enters a room, the user's affiliation is defined as "none"; however, this affiliation does not persist across visits. Owners and admins are by definition immune from certain actions. Specifically, an owner or admin cannot be kicked from a room and cannot be banned from a room. An admin must first lose his or her affiliation (i.e., have an affiliation of "none" or "member") before such actions could be performed on them. The member affiliation provides a way for a room owner or admin to specify a "whitelist" of users who are allowed to enter a members-only room. When a member enters a members-only room, his or her affiliation does not change, no matter what his or her role is. The member affiliation also provides a way for users to effectively register with an open room and thus be permanently associated with that room in some way (one result may be that the user's nickname is reserved in the room). An outcast is a user who has been banned from a room and who is not allowed to enter the room. Whenever a user's affiliation is changed Smack will trigger specific events. **Usage** In order to grant membership to a room, administrator privileges or owner priveliges just send **grantMembership(String jid)**, **grantAdmin(String jid)** or **grantOwnership(String jid)** to _**MultiUserChat**_ respectively. Use **revokeMembership(String jid)**, **revokeAdmin(String jid)** or **revokeOwnership(String jid)** to revoke the membership to a room, administrator privileges or owner priveliges respectively. In order to ban a user from the room just send the message **banUser(String jid, String reason)** to _**MultiUserChat**_. Smack allows you to listen for affiliation modification events. If you are interested in listening affiliation modification events of any user then use the listener **_ParticipantStatusListener_**. But if you are interested in listening for your own affiliation modification events, use the listener **_UserStatusListener_**. Both listeners should be added to the _**MultiUserChat**_ by using **addParticipantStatusListener(ParticipantStatusListener listener)** or **addUserStatusListener(UserStatusListener listener)** respectively. These listeners include several notification events but you may be interested in just a few of them. Smack provides default implementations for these listeners avoiding you to implement all the interfaces' methods. The default implementations are **_DefaultUserStatusListener_** and **_DefaultParticipantStatusListener_**. Below you will find the sent messages to the listeners whenever a user's affiliation has changed. These are the triggered events when the affiliation has been upgraded: | Old | New | Events | |-----|-----|--------| | None | Member | membershipGranted | | Member | Admin | membershipRevoked + adminGranted | | Admin | Owner | adminRevoked + ownershipGranted | | None | Admin | adminGranted | | None | Owner | ownershipGranted | | Member | Owner | membershipRevoked + ownershipGranted | These are the triggered events when the affiliation has been downgraded: | Old | New | Events | |-----|-----|--------| | Owner | Admin | ownershipRevoked + adminGranted | | Admin | Member | adminRevoked + membershipGranted | | Member | None | membershipRevoked | | Owner | Member | ownershipRevoked + membershipGranted | | Owner | None | ownershipRevoked | | Admin | None | adminRevoked | | _Anyone_ | Outcast | banned | **Examples** In this example we can see how to grant admin privileges to a user and listen for the notification events: ```java // User1 creates a room muc = manager.getMultiUserChat("myroom@conference.jabber.org"); muc.create("testbot"); // User1 (which is the room owner) configures the room as a moderated room Form form = muc.getConfigurationForm(); Form answerForm = form.createAnswerForm(); answerForm.setAnswer("muc#roomconfig_moderatedroom", "1"); muc.sendConfigurationForm(answerForm); // User2 joins the new room (as a visitor) MultiUserChat muc2 = manager2.getMultiUserChat("myroom@conference.jabber.org"); muc2.join("testbot2"); // User2 will listen for his own admin privileges muc2.addUserStatusListener(new DefaultUserStatusListener() { public void membershipRevoked() { super.membershipRevoked(); ... } public void adminGranted() { super.adminGranted(); ... } }); // User3 joins the new room (as a visitor) MultiUserChat muc3 = manager3.getMultiUserChat("myroom@conference.jabber.org"); muc3.join("testbot3"); // User3 will lister for other users admin privileges muc3.addParticipantStatusListener(new DefaultParticipantStatusListener() { public void membershipRevoked(String participant) { super.membershipRevoked(participant); ... } public void adminGranted(String participant) { super.adminGranted(participant); ... } }); // The room's owner grants admin privileges to user2 muc.grantAdmin("user2@jabber.org"); ```