@Override
    public Host getHost(HostId hostId) {
        checkPermission(HOST_READ);
        checkNotNull(hostId, HOST_ID_NULL);
        return store.getHost(hostId);
    }
@Test
    public void hostVanishedWithMultipleProviders() {
        detect(HID1, MAC1, VLAN1, LOC1, IP1);
        configured(HID2, MAC2, VLAN2, LOC2, IP2);

        providerService2.hostVanished(HID1);
        assertNull("Should be able to remove learnt host", mgr.getHost(HID1));

        providerService.hostVanished(HID2);
        assertNotNull("Should not be able to remove configured host since the provider is different",
                mgr.getHost(HID2));

        providerService2.hostVanished(HID2);
        assertNull("Should be able to remove configured host when provider is the same",
                mgr.getHost(HID2));
    }