org.apache.hadoop.net
Class CachedDNSToSwitchMapping

java.lang.Object
  extended by org.apache.hadoop.net.CachedDNSToSwitchMapping
All Implemented Interfaces:
DNSToSwitchMapping
Direct Known Subclasses:
ScriptBasedMapping

public class CachedDNSToSwitchMapping
extends Object
implements DNSToSwitchMapping

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.


Field Summary
protected  DNSToSwitchMapping rawMapping
           
 
Constructor Summary
CachedDNSToSwitchMapping(DNSToSwitchMapping rawMapping)
           
 
Method Summary
 List<String> resolve(List<String> names)
          Resolves a list of DNS-names/IP-addresses and returns back a list of switch information (network paths).
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

rawMapping

protected DNSToSwitchMapping rawMapping
Constructor Detail

CachedDNSToSwitchMapping

public CachedDNSToSwitchMapping(DNSToSwitchMapping rawMapping)
Method Detail

resolve

public List<String> resolve(List<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 - x.y.com. 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.

Specified by:
resolve in interface DNSToSwitchMapping
Returns:
list of resolved network paths


Copyright © 2009 The Apache Software Foundation