org.apache.cassandra.locator

Class NetworkTopologyStrategy

java.lang.Object

org.apache.cassandra.locator.AbstractReplicationStrategy

org.apache.cassandra.locator.NetworkTopologyStrategy

public class NetworkTopologyStrategy
extends AbstractReplicationStrategy

This Replication Strategy takes a property file that gives the intended replication factor in each datacenter. The sum total of the datacenter replication factor values should be equal to the keyspace replication factor.

So for example, if the keyspace replication factor is 6, the datacenter replication factors could be 3, 2, and 1 - so 3 replicas in one datacenter, 2 in another, and 1 in another - totalling 6.

This class also caches the Endpoints and invalidates the cache if there is a change in the number of tokens.

Field Summary

Fields inherited from class org.apache.cassandra.locator.AbstractReplicationStrategy

configOptions, snitch

Constructor Summary

Constructors

Constructor and Description
NetworkTopologyStrategy(java.lang.String keyspaceName, TokenMetadata tokenMetadata, IEndpointSnitch snitch, java.util.Map<java.lang.String,java.lang.String> configOptions)

Method Summary

Modifier and Type	Method and Description
java.util.List<java.net.InetAddress>	calculateNaturalEndpoints(Token searchToken, TokenMetadata tokenMetadata) calculate endpoints in one pass through the tokens by tracking our progress in each DC.
java.util.Set<java.lang.String>	getDatacenters()
int	getReplicationFactor() calculate the RF based on strategy_options.
int	getReplicationFactor(java.lang.String dc)
boolean	hasSameSettings(AbstractReplicationStrategy other)
void	validateOptions()

Methods inherited from class org.apache.cassandra.locator.AbstractReplicationStrategy

createReplicationStrategy, getAddressRanges, getAddressRanges, getCachedEndpoints, getClass, getNaturalEndpoints, getPendingAddressRanges, getPendingAddressRanges, getRangeAddresses, getWriteResponseHandler, recognizedOptions, validateReplicationFactor, validateReplicationStrategy

Methods inherited from class java.lang.Object

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

Constructor Detail

NetworkTopologyStrategy

public NetworkTopologyStrategy(java.lang.String keyspaceName,
                               TokenMetadata tokenMetadata,
                               IEndpointSnitch snitch,
                               java.util.Map<java.lang.String,java.lang.String> configOptions)
                        throws ConfigurationException

Throws:

ConfigurationException

Method Detail

calculateNaturalEndpoints

public java.util.List<java.net.InetAddress> calculateNaturalEndpoints(Token searchToken,
                                                                      TokenMetadata tokenMetadata)

calculate endpoints in one pass through the tokens by tracking our progress in each DC.

Specified by:

calculateNaturalEndpoints in class AbstractReplicationStrategy

Parameters:

searchToken - the token the natural endpoints are requested for

Returns:

a copy of the natural endpoints for the given token

See Also:

AbstractReplicationStrategy.getNaturalEndpoints(org.apache.cassandra.dht.RingPosition)

getReplicationFactor

public int getReplicationFactor()

Description copied from class: AbstractReplicationStrategy

calculate the RF based on strategy_options. When overwriting, ensure that this get() is FAST, as this is called often.

Specified by:

getReplicationFactor in class AbstractReplicationStrategy

Returns:

the replication factor

getReplicationFactor

public int getReplicationFactor(java.lang.String dc)

getDatacenters

public java.util.Set<java.lang.String> getDatacenters()

validateOptions

public void validateOptions()
                     throws ConfigurationException

Specified by:

validateOptions in class AbstractReplicationStrategy

Throws:

ConfigurationException

hasSameSettings

public boolean hasSameSettings(AbstractReplicationStrategy other)

Overrides:

hasSameSettings in class AbstractReplicationStrategy