Class CachedDNSToSwitchMapping

  • All Implemented Interfaces:
    Configurable, DNSToSwitchMapping
    Direct Known Subclasses:

    public class CachedDNSToSwitchMapping
    extends AbstractDNSToSwitchMapping
    A cached implementation of DNSToSwitchMapping that takes an raw DNSToSwitchMapping and stores the resolved network location in a cache. The following calls to a resolved network location will get its location from the cache.
    • Constructor Detail

      • CachedDNSToSwitchMapping

        public CachedDNSToSwitchMapping​(DNSToSwitchMapping rawMapping)
        Cache a raw DNS mapping.
        rawMapping - the raw mapping to cache
    • Method Detail

      • useHostName

        public boolean useHostName()
        Description copied from interface: DNSToSwitchMapping
        Hints what to use with implementation when InetSocketAddress is converted to String: hostname (addr.getHostName(), default) or IP address (addr.getAddress().getHostAddress()).
        true if hostname, false if IP address. Default is true.
      • resolve

        public java.util.List<java.lang.String> resolve​(java.util.List<java.lang.String> names)
        Description copied from interface: DNSToSwitchMapping
        Resolves a list of DNS-names/IP-addresses and returns back a list of switch information (network paths). One-to-one correspondence must be maintained between the elements in the lists. Consider an element in the argument list - The switch information that is returned must be a network path of the form /foo/rack, where / is the root, and 'foo' is the switch where 'rack' is connected. Note the hostname/ip-address is not part of the returned path. The network topology of the cluster would determine the number of components in the network path.

        If a name cannot be resolved to a rack, the implementation should return NetworkTopology.DEFAULT_REGION_AND_RACK. This is what the bundled implementations do, though it is not a formal requirement

        names - the list of hosts to resolve (can be empty)
        list of resolved network paths. If names is empty, the returned list is also empty
      • getSwitchMap

        public java.util.Map<java.lang.String,​java.lang.String> getSwitchMap()
        Get the (host x switch) map.
        getSwitchMap in class AbstractDNSToSwitchMapping
        a copy of the cached map of hosts to rack
      • toString

        public java.lang.String toString()
        toString in class java.lang.Object
      • reloadCachedMappings

        public void reloadCachedMappings()
        Description copied from interface: DNSToSwitchMapping
        Reload all of the cached mappings.

        If there is a cache, this method will clear it, so that future accesses will get a chance to see the new data.