public class RoundRobinPolicy extends Object implements LoadBalancingPolicy
DCAwareRoundRobinPolicy
load balancing policy instead.Constructor and Description |
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RoundRobinPolicy()
Creates a load balancing policy that picks host to query in a round robin
fashion (on all the hosts of the Cassandra cluster).
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Modifier and Type | Method and Description |
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void |
close()
Gets invoked at cluster shutdown.
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HostDistance |
distance(Host host)
Return the HostDistance for the provided host.
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void |
init(Cluster cluster,
Collection<Host> hosts)
Initialize this load balancing policy.
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Iterator<Host> |
newQueryPlan(String loggedKeyspace,
Statement statement)
Returns the hosts to use for a new query.
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void |
onAdd(Host host)
Called when a new node is added to the cluster.
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void |
onDown(Host host)
Called when a node is determined to be down.
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void |
onRemove(Host host)
Called when a node is removed from the cluster.
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void |
onUp(Host host)
Called when a node is determined to be up.
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public RoundRobinPolicy()
public void init(Cluster cluster, Collection<Host> hosts)
LoadBalancingPolicy
init
in interface LoadBalancingPolicy
cluster
- the Cluster
instance for which the policy is created.hosts
- the initial hosts to use.public HostDistance distance(Host host)
DCAwareRoundRobinPolicy
instead.distance
in interface LoadBalancingPolicy
host
- the host of which to return the distance of.host
.public Iterator<Host> newQueryPlan(String loggedKeyspace, Statement statement)
i
th host of the plans returned will cycle
over all the hosts of the cluster in a round-robin fashion.newQueryPlan
in interface LoadBalancingPolicy
loggedKeyspace
- the keyspace currently logged in on for this
query.statement
- the query for which to build the plan.public void onUp(Host host)
LoadBalancingPolicy
onUp
in interface LoadBalancingPolicy
host
- the host that has been detected up.public void onDown(Host host)
LoadBalancingPolicy
onDown
in interface LoadBalancingPolicy
host
- the host that has been detected down.public void onAdd(Host host)
LoadBalancingPolicy
onAdd
in interface LoadBalancingPolicy
host
- the host that has been newly added.public void onRemove(Host host)
LoadBalancingPolicy
onRemove
in interface LoadBalancingPolicy
host
- the removed host.public void close()
LoadBalancingPolicy
close
in interface LoadBalancingPolicy
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