@Override
        public boolean equals(Object o)
        {
            if (this == o) return true;
            if (o == null || getClass() != o.getClass()) return false;
            Messages messages = (Messages) o;
            return history.equals(messages.history);
        }
A wrapper for a collection of Message instances that is cached.
xmppserver/src/main/java/org/jivesoftware/openfire/muc/HistoryStrategy.java