public String canSendPrivateMessage() {
        return canSendPrivateMessage == null ? "anyone" : canSendPrivateMessage;
    }
Returns the minimal role of persons that are allowed to send private messages in the room. The returned value is
any one of: "anyone", "moderators", "participants", "none".

@return The minimal role of persons that are allowed to send private messages in the room (never null).
xmppserver/src/main/java/org/jivesoftware/openfire/muc/MUCRoom.java