public void setContext(String subdomain, String prefix) {
        this.contextSubdomain = subdomain;
        this.contextPrefix = prefix;
        setTypeFromString(MUCPersistenceManager.getProperty(subdomain, prefix + ".type"));
        String maxNumberString = MUCPersistenceManager.getProperty(subdomain, prefix + ".maxNumber");
        if (maxNumberString != null && !maxNumberString.trim().isEmpty()){
            try {
                this.maxNumber = Integer.parseInt(maxNumberString);
            }
            catch (Exception e){
                Log.info("Jive property " + prefix + ".maxNumber not a valid number.");
            }
        }
    }
Sets the prefix to use for retrieving and saving settings (and also
triggers an immediate loading of properties).

@param subdomain the subdomain of the muc service to pull properties for.
@param prefix the prefix to use (without trailing dot) on property names.
xmppserver/src/main/java/org/jivesoftware/openfire/muc/HistoryStrategy.java