org.apache.storm.networktopography

Class AbstractDNSToSwitchMapping

java.lang.Object

org.apache.storm.networktopography.AbstractDNSToSwitchMapping

All Implemented Interfaces:

DNSToSwitchMapping

Direct Known Subclasses:

AlternateRackDNSToSwitchMapping, DefaultRackDNSToSwitchMapping

public abstract class AbstractDNSToSwitchMapping
extends Object
implements DNSToSwitchMapping

This is a base class for DNS to Switch mappings.

It is not mandatory to derive DNSToSwitchMapping implementations from it, but it is strongly recommended, as it makes it easy for the developers to add new methods to this base class that are automatically picked up by all implementations.

Field Summary

Fields inherited from interface org.apache.storm.networktopography.DNSToSwitchMapping

DEFAULT_RACK

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractDNSToSwitchMapping() Create an unconfigured instance.

Method Summary

Modifier and Type	Method and Description
String	dumpTopology() Generate a string listing the switch mapping implementation, the mapping for every known node and the number of nodes and unique switches known about -each entry to a separate line.
Map<String,String>	getSwitchMap() Get a copy of the map (for diagnostics).
boolean	isSingleSwitch() Predicate that indicates that the switch mapping is known to be single-switch.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.storm.networktopography.DNSToSwitchMapping

resolve

Constructor Detail

AbstractDNSToSwitchMapping

protected AbstractDNSToSwitchMapping()

Create an unconfigured instance.

Method Detail

isSingleSwitch

public boolean isSingleSwitch()

Predicate that indicates that the switch mapping is known to be single-switch. The base class returns false: it assumes all mappings are multi-rack. Subclasses may override this with methods that are more aware of their topologies.

Returns:

true if the mapping thinks that it is on a single switch

getSwitchMap

public Map<String,String> getSwitchMap()

Get a copy of the map (for diagnostics).

Returns:

a clone of the map or null for none known

dumpTopology

public String dumpTopology()

Generate a string listing the switch mapping implementation, the mapping for every known node and the number of nodes and unique switches known about -each entry to a separate line.

Returns:

a string that can be presented to the ops team or used in debug messages.