public static void Init(Configuration conf)
{
lock (typeof(RackResolver))
{
if (initCalled)
{
return;
}
else
{
initCalled = true;
}
Type dnsToSwitchMappingClass = conf.GetClass <DNSToSwitchMapping>(CommonConfigurationKeysPublic
.NetTopologyNodeSwitchMappingImplKey, typeof(ScriptBasedMapping));
try
{
DNSToSwitchMapping newInstance = ReflectionUtils.NewInstance(dnsToSwitchMappingClass
, conf);
// Wrap around the configured class with the Cached implementation so as
// to save on repetitive lookups.
// Check if the impl is already caching, to avoid double caching.
dnsToSwitchMapping = ((newInstance is CachedDNSToSwitchMapping) ? newInstance : new
CachedDNSToSwitchMapping(newInstance));
}
catch (Exception e)
{
throw new RuntimeException(e);
}
}
}
/// <summary>
/// Query for a
/// <see cref="DNSToSwitchMapping"/>
/// instance being on a single
/// switch.
/// <p/>
/// This predicate simply assumes that all mappings not derived from
/// this class are multi-switch.
/// </summary>
/// <param name="mapping">the mapping to query</param>
/// <returns>
/// true if the base class says it is single switch, or the mapping
/// is not derived from this class.
/// </returns>
public static bool IsMappingSingleSwitch(DNSToSwitchMapping mapping)
{
return(mapping != null && mapping is Org.Apache.Hadoop.Net.AbstractDNSToSwitchMapping &&
((Org.Apache.Hadoop.Net.AbstractDNSToSwitchMapping)mapping).IsSingleSwitch());
}
/// <summary>Create an instance from the given raw mapping</summary>
/// <param name="rawMap">raw DNSTOSwithMapping</param>
public ScriptBasedMapping(DNSToSwitchMapping rawMap)
: base(rawMap)
{
}
/// <summary>cache a raw DNS mapping</summary>
/// <param name="rawMapping">the raw mapping to cache</param>
public CachedDNSToSwitchMapping(DNSToSwitchMapping rawMapping)
{
this.rawMapping = rawMapping;
}
private void AssertMultiSwitch(DNSToSwitchMapping mapping)
{
Assert.Equal("Expected a multi switch mapping " + mapping, false
, AbstractDNSToSwitchMapping.IsMappingSingleSwitch(mapping));
}
private void AssertSingleSwitch(DNSToSwitchMapping mapping)
{
Assert.Equal("Expected a single switch mapping " + mapping, true
, AbstractDNSToSwitchMapping.IsMappingSingleSwitch(mapping));
}
