Module org.elasticsearch.server
Package org.elasticsearch.cluster

Class ClusterStateObserver

java.lang.Object
org.elasticsearch.cluster.ClusterStateObserver
public class ClusterStateObserver extends 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.

  • Field Details

    • logger

      protected final org.apache.logging.log4j.Logger logger

    • NON_NULL_MASTER_PREDICATE

      public static final Predicate<ClusterState> NON_NULL_MASTER_PREDICATE

  • Constructor Details

    • ClusterStateObserver

      public ClusterStateObserver(ClusterService clusterService, @Nullable TimeValue timeout, org.apache.logging.log4j.Logger 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

    • ClusterStateObserver

      public ClusterStateObserver(ClusterState initialState, ClusterService clusterService, @Nullable TimeValue timeout, org.apache.logging.log4j.Logger 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

    • ClusterStateObserver

      public ClusterStateObserver(long initialVersion, ClusterApplierService clusterApplierService, @Nullable TimeValue timeout, org.apache.logging.log4j.Logger logger, ThreadContext contextHolder)

  • Method Details

    • setAndGetObservedState

      public ClusterState setAndGetObservedState()
      sets the last observed state to the currently applied cluster state and returns it

    • isTimedOut

      public boolean isTimedOut()
      indicates whether this observer has timed out

    • waitForNextChange

      public void waitForNextChange(ClusterStateObserver.Listener listener)

    • waitForNextChange

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

    • waitForNextChange

      public void waitForNextChange(ClusterStateObserver.Listener listener, Predicate<ClusterState> statePredicate)

    • waitForNextChange

      public void waitForNextChange(ClusterStateObserver.Listener listener, Predicate<ClusterState> statePredicate, @Nullable TimeValue timeOutValue)
      Wait for the next cluster state which satisfies statePredicate
      Parameters:
      listener - callback listener
      statePredicate - 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.

    • waitForState

      public static void waitForState(ClusterService clusterService, ThreadContext threadContext, ClusterStateObserver.Listener listener, Predicate<ClusterState> statePredicate, @Nullable TimeValue timeout, org.apache.logging.log4j.Logger logger)
      Waits for the cluster state to match a given predicate. Unlike waitForNextChange(org.elasticsearch.cluster.ClusterStateObserver.Listener) this method checks whether the current state matches the predicate first and resolves the listener directly if it matches without waiting for another cluster state update.
      Parameters:
      clusterService - cluster service
      threadContext - thread context to resolve listener in
      listener - listener to resolve once state matches the predicate
      statePredicate - predicate the cluster state has to match
      timeout - timeout for the wait or null for no timeout
      logger - logger to use for logging observer messages