public class LatencyAwarePolicy extends Object implements ChainableLoadBalancingPolicy
LatencyAwarePolicy.Builder
class and methods for more details on the
possible parameters of this policy.Modifier and Type | Class and Description |
---|---|
static class |
LatencyAwarePolicy.Builder
Helper builder object to create a latency aware policy.
|
static class |
LatencyAwarePolicy.Snapshot
An immutable snapshot of the per-host scores (and stats in general)
maintained by
LatencyAwarePolicy to base its decision upon. |
Modifier and Type | Method and Description |
---|---|
static LatencyAwarePolicy.Builder |
builder(LoadBalancingPolicy childPolicy)
Creates a new latency aware policy builder given the child policy
that the resulting policy should wrap.
|
void |
close()
Gets invoked at cluster shutdown.
|
HostDistance |
distance(Host host)
Returns the HostDistance for the provided host.
|
LoadBalancingPolicy |
getChildPolicy()
Returns the child policy.
|
LatencyAwarePolicy.Snapshot |
getScoresSnapshot()
Returns a snapshot of the scores (latency averages) maintained by this
policy.
|
void |
init(Cluster cluster,
Collection<Host> hosts)
Initialize this load balancing policy.
|
Iterator<Host> |
newQueryPlan(String loggedKeyspace,
Statement statement)
Returns the hosts to use for a new query.
|
void |
onAdd(Host host)
Called when a new node is added to the cluster.
|
void |
onDown(Host host)
Called when a node is determined to be down.
|
void |
onRemove(Host host)
Called when a node is removed from the cluster.
|
void |
onUp(Host host)
Called when a node is determined to be up.
|
public LoadBalancingPolicy getChildPolicy()
ChainableLoadBalancingPolicy
getChildPolicy
in interface ChainableLoadBalancingPolicy
public static LatencyAwarePolicy.Builder builder(LoadBalancingPolicy childPolicy)
childPolicy
- the load balancing policy to wrap with latency
awareness.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)
distance
in interface LoadBalancingPolicy
host
- the host of which to return the distance of.host
as returned by the wrapped policy.public Iterator<Host> newQueryPlan(String loggedKeyspace, Statement statement)
newQueryPlan
in interface LoadBalancingPolicy
loggedKeyspace
- the currently logged keyspace.statement
- the statement for which to build the plan.public LatencyAwarePolicy.Snapshot getScoresSnapshot()
LatencyAwarePolicy.Snapshot
object containing the current
latency scores maintained by this policy.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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