public static Collection<ExternalComponentConfiguration> getAllowedComponents() {
        return getConfigurations(Permission.allowed);
    }
Returns the list of registered external components that are allowed to connect to this
server when using a whitelist policy. However, when using a blacklist policy (i.e. anyone
may connect to the server) the returned list of configurations will be used for obtaining
the shared secret specific for each component.

@return the configuration of the registered external components.
xmppserver/src/main/java/org/jivesoftware/openfire/component/ExternalComponentManager.java