001/**
002 *
003 * Copyright 2003-2007 Jive Software.
004 *
005 * Licensed under the Apache License, Version 2.0 (the "License");
006 * you may not use this file except in compliance with the License.
007 * You may obtain a copy of the License at
008 *
009 *     http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.jivesoftware.smack;
019
020import org.jivesoftware.smack.packet.Presence;
021
022import java.util.Collection;
023
024/**
025 * A listener that is fired any time a roster is changed or the presence of
026 * a user in the roster is changed.
027 * 
028 * @see Roster#addRosterListener(RosterListener)
029 * @author Matt Tucker
030 */
031public interface RosterListener {
032
033    /**
034     * Called when roster entries are added.
035     *
036     * @param addresses the XMPP addresses of the contacts that have been added to the roster.
037     */
038    public void entriesAdded(Collection<String> addresses);
039
040    /**
041     * Called when a roster entries are updated.
042     *
043     * @param addresses the XMPP addresses of the contacts whose entries have been updated.
044     */
045    public void entriesUpdated(Collection<String> addresses);
046
047    /**
048     * Called when a roster entries are removed.
049     *
050     * @param addresses the XMPP addresses of the contacts that have been removed from the roster.
051     */
052    public void entriesDeleted(Collection<String> addresses);
053
054    /**
055     * Called when the presence of a roster entry is changed. Care should be taken
056     * when using the presence data delivered as part of this event. Specifically,
057     * when a user account is online with multiple resources, the UI should account
058     * for that. For example, say a user is online with their desktop computer and
059     * mobile phone. If the user logs out of the IM client on their mobile phone, the
060     * user should not be shown in the roster (contact list) as offline since they're
061     * still available as another resource.<p>
062     *
063     * To get the current "best presence" for a user after the presence update, query the roster:
064     * <pre>
065     *    String user = presence.getFrom();
066     *    Presence bestPresence = roster.getPresence(user);
067     * </pre>
068     *
069     * That will return the presence value for the user with the highest priority and
070     * availability.
071     *
072     * Note that this listener is triggered for presence (mode) changes only
073     * (e.g presence of types available and unavailable. Subscription-related
074     * presence packets will not cause this method to be called.
075     *
076     * @param presence the presence that changed.
077     * @see Roster#getPresence(String)
078     */
079    public void presenceChanged(Presence presence);
080}