public class PagingOptimizingLoadBalancingPolicy extends Object implements LoadBalancingPolicy
| Constructor and Description |
|---|
PagingOptimizingLoadBalancingPolicy(LoadBalancingPolicy loadBalancingPolicy) |
| Modifier and Type | Method and Description |
|---|---|
void |
close()
Gets invoked at cluster shutdown.
|
HostDistance |
distance(Host host)
Returns the distance assigned by this policy to the provided host.
|
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 PagingOptimizingLoadBalancingPolicy(LoadBalancingPolicy loadBalancingPolicy)
public void init(Cluster cluster, Collection<Host> hosts)
LoadBalancingPolicyNote that the driver guarantees that it will call this method exactly once per policy object and will do so before any call to another of the methods of the policy.
init in interface LoadBalancingPolicycluster - the Cluster instance for which the policy is created.hosts - the initial hosts to use.public HostDistance distance(Host host)
LoadBalancingPolicyThe distance of an host influence how much connections are kept to the node (see HostDistance). A policy should assign a LOCAL distance to nodes that are susceptible
to be returned first by newQueryPlan and it is useless for newQueryPlan to
return hosts to which it assigns an IGNORED distance.
The host distance is primarily used to prevent keeping too many connections to host in remote datacenters when the policy itself always picks host in the local datacenter first.
distance in interface LoadBalancingPolicyhost - the host of which to return the distance of.host.public Iterator<Host> newQueryPlan(String loggedKeyspace, Statement statement)
LoadBalancingPolicyEach new query will call this method. The first host in the result will then be used to
perform the query. In the event of a connection problem (the queried host is down or appear to
be so), the next host will be used. If all hosts of the returned Iterator are down, the
query will fail.
newQueryPlan in interface LoadBalancingPolicyloggedKeyspace - the currently logged keyspace (the one set through either Cluster.connect(String) or by manually doing a USE query) for the session on which
this plan need to be built. This can be null if the corresponding session has no
keyspace logged in.statement - the query for which to build a plan.public void onAdd(Host host)
LoadBalancingPolicyThe newly added node should be considered up.
onAdd in interface LoadBalancingPolicyhost - the host that has been newly added.public void onUp(Host host)
LoadBalancingPolicyonUp in interface LoadBalancingPolicyhost - the host that has been detected up.public void onDown(Host host)
LoadBalancingPolicyonDown in interface LoadBalancingPolicyhost - the host that has been detected down.public void onRemove(Host host)
LoadBalancingPolicyonRemove in interface LoadBalancingPolicyhost - the removed host.public void close()
LoadBalancingPolicyThis gives the policy the opportunity to perform some cleanup, for instance stop threads that it might have started.
close in interface LoadBalancingPolicyCopyright © 2012–2024. All rights reserved.