public static List<String> getProperties(String subdomain, String parent) {
        final MUCServiceProperties props = propertyMaps.computeIfAbsent( subdomain, MUCServiceProperties::new );
        Collection<String> propertyNames = props.getChildrenNames(parent);
        List<String> values = new ArrayList<>();
        for (String propertyName : propertyNames) {
            String value = getProperty(subdomain, propertyName);
            if (value != null) {
                values.add(value);
            }
        }

        return values;
    }
Return all immediate children property values of a parent Jive property as a list of strings,
or an empty list if there are no children. For example, given
the properties {@code X.Y.A}, {@code X.Y.B}, {@code X.Y.C} and {@code X.Y.C.D}, then
the immediate child properties of {@code X.Y} are {@code X.Y.A}, {@code X.Y.B}, and
{@code X.Y.C} (the value of {@code X.Y.C.D} would not be returned using this method).<p>

@param subdomain the subdomain of the service to retrieve a property from
@param parent the name of the parent property to return the children for.
@return all child property values for the given parent.
xmppserver/src/main/java/org/jivesoftware/openfire/muc/spi/MUCPersistenceManager.java