org.elasticsearch.cluster

Class ClusterStateObserver

java.lang.Object

org.elasticsearch.cluster.ClusterStateObserver

public class ClusterStateObserver
extends java.lang.Object

A utility class which simplifies interacting with the cluster state in cases where one tries to take action based on the current state but may want to wait for a new state and retry upon failure.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	ClusterStateObserver.ChangePredicate
static class	ClusterStateObserver.EventPredicate
static interface	ClusterStateObserver.Listener
static class	ClusterStateObserver.ValidationPredicate

Field Summary

Fields

Modifier and Type	Field and Description
protected ESLogger	logger
ClusterStateObserver.ChangePredicate	MATCH_ALL_CHANGES_PREDICATE

Constructor Summary

Constructors

Constructor and Description
ClusterStateObserver(ClusterService clusterService, ESLogger logger, ThreadContext contextHolder)
ClusterStateObserver(ClusterService clusterService, TimeValue timeout, ESLogger logger, ThreadContext contextHolder)

Method Summary

Modifier and Type	Method and Description
boolean	isTimedOut() indicates whether this observer has timedout
ClusterState	observedState() last cluster state observer by this observer.
void	reset(ClusterState toState) reset this observer to the give cluster state.
void	waitForNextChange(ClusterStateObserver.Listener listener)
void	waitForNextChange(ClusterStateObserver.Listener listener, ClusterStateObserver.ChangePredicate changePredicate)
void	waitForNextChange(ClusterStateObserver.Listener listener, ClusterStateObserver.ChangePredicate changePredicate, TimeValue timeOutValue) Wait for the next cluster state which satisfies changePredicate
void	waitForNextChange(ClusterStateObserver.Listener listener, TimeValue timeOutValue)

Methods inherited from class java.lang.Object

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

Field Detail

logger

protected final ESLogger logger

MATCH_ALL_CHANGES_PREDICATE

public final ClusterStateObserver.ChangePredicate MATCH_ALL_CHANGES_PREDICATE

Constructor Detail

ClusterStateObserver

public ClusterStateObserver(ClusterService clusterService,
                            ESLogger logger,
                            ThreadContext contextHolder)

ClusterStateObserver

public ClusterStateObserver(ClusterService clusterService,
                            @Nullable
                            TimeValue timeout,
                            ESLogger logger,
                            ThreadContext contextHolder)

Parameters:

timeout - a global timeout for this observer. After it has expired the observer will fail any existing or new #waitForNextChange calls. Set to null to wait indefinitely

Method Detail

observedState

public ClusterState observedState()

last cluster state observer by this observer. Note that this may not be the current one

isTimedOut

public boolean isTimedOut()

indicates whether this observer has timedout

waitForNextChange

public void waitForNextChange(ClusterStateObserver.Listener listener)

waitForNextChange

public void waitForNextChange(ClusterStateObserver.Listener listener,
                              @Nullable
                              TimeValue timeOutValue)

waitForNextChange

public void waitForNextChange(ClusterStateObserver.Listener listener,
                              ClusterStateObserver.ChangePredicate changePredicate)

waitForNextChange

public void waitForNextChange(ClusterStateObserver.Listener listener,
                              ClusterStateObserver.ChangePredicate changePredicate,
                              @Nullable
                              TimeValue timeOutValue)

Wait for the next cluster state which satisfies changePredicate

Parameters:

listener - callback listener

changePredicate - predicate to check whether cluster state changes are relevant and the callback should be called

timeOutValue - a timeout for waiting. If null the global observer timeout will be used.

reset

public void reset(ClusterState toState)

reset this observer to the give cluster state. Any pending waits will be canceled.