groupmanager.java

基于Jabber协议的即时消息服务器

        groupCache.remove(group.getName());
    }

    /**
     * Deletes a user from all the groups where he/she belongs. The most probable cause
     * for this request is that the user has been deleted from the system.
     *
     * TODO: remove this method and use events instead.
     *
     * @param user the deleted user from the system.
     */
    public void deleteUser(User user) {
        JID userJID = XMPPServer.getInstance().createJID(user.getUsername(), null);
        for (Group group : getGroups(userJID)) {
            if (group.getAdmins().contains(userJID)) {
                if (group.getAdmins().remove(userJID)) {
                    // Remove the group from cache.
                    groupCache.remove(group.getName());
                }
            }
            else {
                if (group.getMembers().remove(userJID)) {
                    // Remove the group from cache.
                    groupCache.remove(group.getName());
                }
            }
        }
    }

    /**
     * Returns the total number of groups in the system.
     *
     * @return the total number of groups.
     */
    public int getGroupCount() {
        Integer count = (Integer)groupMetaCache.get(GROUP_COUNT_KEY);
        if (count == null) {
            synchronized(GROUP_COUNT_KEY.intern()) {
                count = (Integer)groupMetaCache.get(GROUP_COUNT_KEY);
                if (count == null) {
                    count = provider.getGroupCount();
                    groupMetaCache.put(GROUP_COUNT_KEY, count);
                }
            }
        }
        return count;
    }

    /**
     * Returns an unmodifiable Collection of all groups in the system.
     *
     * @return an unmodifiable Collection of all groups.
     */
    public Collection<Group> getGroups() {
        Collection<String> groupNames = (Collection<String>)groupMetaCache.get(GROUP_NAMES_KEY);
        if (groupNames == null) {
            synchronized(GROUP_NAMES_KEY.intern()) {
                groupNames = (Collection<String>)groupMetaCache.get(GROUP_NAMES_KEY);
                if (groupNames == null) {
                    groupNames = provider.getGroupNames();
                    groupMetaCache.put(GROUP_NAMES_KEY, groupNames);
                }
            }
        }
        return new GroupCollection(groupNames);
    }

    /**
     * Returns an unmodifiable Collection of all shared groups in the system.
     *
     * @return an unmodifiable Collection of all shared groups.
     */
    public Collection<Group> getSharedGroups() {
        Collection<String> groupNames = (Collection<String>)groupMetaCache.get(SHARED_GROUPS_KEY);
        if (groupNames == null) {
            synchronized(SHARED_GROUPS_KEY.intern()) {
                groupNames = (Collection<String>)groupMetaCache.get(SHARED_GROUPS_KEY);
                if (groupNames == null) {
                    groupNames = Group.getSharedGroupsNames();
                    groupMetaCache.put(SHARED_GROUPS_KEY, groupNames);
                }
            }
        }
        return new GroupCollection(groupNames);
    }

    /**
     * Returns all groups given a start index and desired number of results. This is
     * useful to support pagination in a GUI where you may only want to display a certain
     * number of results per page. It is possible that the number of results returned will
     * be less than that specified by numResults if numResults is greater than the number
     * of records left in the system to display.
     *
     * @param startIndex start index in results.
     * @param numResults number of results to return.
     * @return an Iterator for all groups in the specified range.
     */
    public Collection<Group> getGroups(int startIndex, int numResults) {
        String key = GROUP_NAMES_KEY + startIndex + "," + numResults;

        Collection<String> groupNames = (Collection<String>)groupMetaCache.get(key);
        if (groupNames == null) {
            synchronized(key.intern()) {
                groupNames = (Collection<String>)groupMetaCache.get(key);
                if (groupNames == null) {
                    groupNames = provider.getGroupNames(startIndex, numResults);
                    groupMetaCache.put(key, groupNames);
                }
            }
        }
        return new GroupCollection(groupNames);
    }

    /**
     * Returns an iterator for all groups that the User is a member of.
     *
     * @param user the user.
     * @return all groups the user belongs to.
     */
    public Collection<Group> getGroups(User user) {
        return getGroups(XMPPServer.getInstance().createJID(user.getUsername(), null));
    }

    /**
     * Returns an iterator for all groups that the entity with the specified JID is a member of.
     *
     * @param user the JID of the entity to get a list of groups for.
     * @return all groups that an entity belongs to.
     */
    public Collection<Group> getGroups(JID user) {
        String key = user.toBareJID();

        Collection<String> groupNames = (Collection<String>)groupMetaCache.get(key);
        if (groupNames == null) {
            synchronized(key.intern()) {
                groupNames = (Collection<String>)groupMetaCache.get(key);
                if (groupNames == null) {
                    groupNames = provider.getGroupNames(user);
                    groupMetaCache.put(key, groupNames);
                }
            }
        }
        return new GroupCollection(groupNames);
    }

    /**
     * Returns true if groups are read-only.
     *
     * @return true if groups are read-only.
     */
    public boolean isReadOnly() {
        return provider.isReadOnly();
    }

    /**
     * Returns true if searching for groups is supported.
     *
     * @return true if searching for groups are supported.
     */
    public boolean isSearchSupported() {
        return provider.isSearchSupported();
    }

    /**
     * Returns the groups that match the search. The search is over group names and
     * implicitly uses wildcard matching (although the exact search semantics are left
     * up to each provider implementation). For example, a search for "HR" should match
     * the groups "HR", "HR Department", and "The HR People".<p>
     *
     * Before searching or showing a search UI, use the {@link #isSearchSupported} method
     * to ensure that searching is supported.
     *
     * @param query the search string for group names.
     * @return all groups that match the search.
     */
    public Collection<Group> search(String query) {
        Collection<String> groupNames = provider.search(query);
        return new GroupCollection(groupNames);
    }

    /**
     * Returns the groups that match the search given a start index and desired number
     * of results. The search is over group names and implicitly uses wildcard matching
     * (although the exact search semantics are left up to each provider implementation).
     * For example, a search for "HR" should match the groups "HR", "HR Department", and
     * "The HR People".<p>
     *
     * Before searching or showing a search UI, use the {@link #isSearchSupported} method
     * to ensure that searching is supported.
     *
     * @param query the search string for group names.
     * @return all groups that match the search.
     */
    public Collection<Group> search(String query, int startIndex, int numResults) {
        Collection<String> groupNames = provider.search(query, startIndex, numResults);
        return new GroupCollection(groupNames);
    }

    /**
     * Returns the configured group provider. Note that this method has special access
     * privileges since only a few certain classes need to access the provider directly.
     *
     * @return the group provider.
     */
    public GroupProvider getProvider() {
        return provider;
    }
}