public synchronized Group getGroup(int gid) { return (Group)groups.get(gid);
public synchronized Group getGroup(String name) { Group group; for (Iterator i = groups.values().iterator(); i.hasNext();) { group = (Group) i.next(); if (group.getName().equals(name)) return group; } return null;
	public synchronized Group getGroup(int gid) {		return (Group)groups.get(gid);	}