Package de.aristaflow.adept2.core.registry.cluster

Class ClusterNodeState

java.lang.Object
de.aristaflow.adept2.core.registry.cluster.ClusterNodeState
public class ClusterNodeState extends Object
This class encapsulates the state of a cluster node in memory. It also provides control data like restarting or shutting down. Package-scoped methods are only called from the corresponding ClusterNode. Both classes interact closely with respect to field access and locking.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    protected AbortServiceException
    aseBlocker
    An AbortServiceException that occurred and blocks the cluster node from continuing.
    protected String
    clusterName
    The cluster name of the node.
    protected final Lock
    controlLock
    The lock required to control the cluster node.
    protected final Condition
    controlSignal
    The condition for the node control to wait for external signals, e.
    protected Set<Thread>
    currentStatusChangeWaiters
    The threads that await statusChange which has been signalled.
    protected Error
    errBlocker
    An Error that occurred and blocks the cluster node from continuing.
    protected boolean
    isServer
    Whether the cluster node is a server node.
    protected long
    lastStatusUpdate
    The time the status has been updated the last time.
    protected final String
    name
    The name of the cluster node.
    protected Set<Thread>
    nextStatusChangeWaiters
    The threads that await statusChange and have arrived after its last signalling.
    protected final Thread
    nodeControl
    The thread controlling the cluster node, that is it handles the complete node lifecycle including restarting and thus changing roles.
    protected boolean
    restarting
    Whether the control thread has accepted a restarting request and is currently restarting.
    protected boolean
    restartRequested
    Whether a restart has been requested from the outside or becomes necessary due to internal problems.
    protected long
    runningSince
    The time since the cluster node is running (value stems from the database).
    protected boolean
    shutdown
    Whether a shutdown has been requested from the outside or becomes necessary due to internal problems.
    protected Status
    status
    The current status of the cluster node.
    protected final Condition
    statusChange
    The condition of the control lock for threads that wait for a specific status, awaitStatus(long, Status...).
    protected final Condition
    statusChangeWaitersLeft
    The condition of the control lock to let node control wait for all threads currently waiting for statusChange.

  • Method Summary

    Modifier and Type
    Method
    Description
    Triple<Status,Long,Long>
    awaitStatus(long timeout, Status... statuses)
    Waits until the cluster node reaches one of the designated statuses or until the designated timeout elapsed.
    String
    getClusterName()
    Gets the name of the cluster of this node if available.
    String
    getClusterNodeName()
    Gets the complete name of this cluster node, that is the name of the cluster (if available) and the node name.
    protected String
    getLogName()
    Gets the name of the cluster together with whether it is a server or client cluster node.
    String
    getName()
    Gets the name of the cluster node.
    Triple<Status,Long,Long>
    getStatus()
    Gets the current status of the cluster node without waiting.

    Methods inherited from class java.lang.Object

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

  • Field Details

    • name

      protected final String name
      The name of the cluster node. If none is provided via the configuration, a random default value is chosen automatically.

    • clusterName

      protected String clusterName
      The cluster name of the node. This is only be available while a cluster platform exists.

    • isServer

      protected volatile boolean isServer
      Whether the cluster node is a server node.

    • shutdown

      protected volatile boolean shutdown
      Whether a shutdown has been requested from the outside or becomes necessary due to internal problems.

    • restartRequested

      protected volatile boolean restartRequested
      Whether a restart has been requested from the outside or becomes necessary due to internal problems.

    • restarting

      protected volatile boolean restarting
      Whether the control thread has accepted a restarting request and is currently restarting. While restarting further restart requests have to be ignored.

    • status

      protected volatile Status status
      The current status of the cluster node. This corresponds to the value in the corresponding table – usually a bit delayed.

    • lastStatusUpdate

      protected volatile long lastStatusUpdate
      The time the status has been updated the last time. Asynchronous requests needs this to detect whether the node control has responded to the request.

    • runningSince

      protected volatile long runningSince
      The time since the cluster node is running (value stems from the database).

    • aseBlocker

      protected AbortServiceException aseBlocker
      An AbortServiceException that occurred and blocks the cluster node from continuing.

    • errBlocker

      protected Error errBlocker
      An Error that occurred and blocks the cluster node from continuing.

    • nodeControl

      protected final Thread nodeControl
      The thread controlling the cluster node, that is it handles the complete node lifecycle including restarting and thus changing roles. When changing the node state the name of this thread will be adapted appropriately to reflect the current status.

    • controlLock

      protected final Lock controlLock
      The lock required to control the cluster node. This includes control operations like starting, terminating and restarting but also status changes.

    • controlSignal

      protected final Condition controlSignal
      The condition for the node control to wait for external signals, e. g. restart(long).

    • statusChange

      protected final Condition statusChange
      The condition of the control lock for threads that wait for a specific status, awaitStatus(long, Status...).

    • nextStatusChangeWaiters

      protected volatile Set<Thread> nextStatusChangeWaiters
      The threads that await statusChange and have arrived after its last signalling.

    • currentStatusChangeWaiters

      protected volatile Set<Thread> currentStatusChangeWaiters
      The threads that await statusChange which has been signalled. This threads have to leave (if their condition is right). This prevents threads waiting for statusChange to miss signals.

    • statusChangeWaitersLeft

      protected final Condition statusChangeWaitersLeft
      The condition of the control lock to let node control wait for all threads currently waiting for statusChange. This is signalled as soon as currentStatusChangeWaiters is empty.

  • Method Details

    • getName

      public String getName()
      Gets the name of the cluster node. This is independent from the status and created once for the complete lifetime of a ClusterNode.
      Returns:
      The name of the cluster node.

    • getClusterName

      public String getClusterName()
      Gets the name of the cluster of this node if available. null if there is currently no platform.
      Returns:
      The name of the cluster of this node or null if there is no current platform.

    • getClusterNodeName

      public String getClusterNodeName()
      Gets the complete name of this cluster node, that is the name of the cluster (if available) and the node name.
      Returns:
      The complete name of this cluster node, that is the name of the cluster (if available) and the node name.

    • getLogName

      protected String getLogName()
      Gets the name of the cluster together with whether it is a server or client cluster node. Use this in log messages.
      Returns:
      The name of the cluster together with whether it is a server or client cluster node for usage in log messages.

    • getStatus

      public Triple<Status,Long,Long> getStatus() throws AbortServiceException
      Gets the current status of the cluster node without waiting.
      Returns:
      The current status of this cluster node, the time of the last status update and the time since when this node is running.
      Throws:
      AbortServiceException - If there are non-recoverable problems with the cluster especially when bootstrapping, an AbortServiceException will be thrown. This exception indicates that the status is Status.TERMINATED.

    • awaitStatus

      public Triple<Status,Long,Long> awaitStatus(long timeout, Status... statuses) throws InterruptedException, AbortServiceException
      Waits until the cluster node reaches one of the designated statuses or until the designated timeout elapsed. The reached status will be returned or null in case the timeout elapsed before one of these statuses has been reached.
      If the node control is not running any more, Status.TERMINATED will remain the status and no waiting will take place.
      Parameters:
      timeout - The time in milliseconds to wait for the cluster node to reach one of the designated statuses. Use 0 to not wait at all or a negative value to wait without time limit. The time required for the lock will count to this timeout.
      statuses - The statuses which should be reached by this cluster node.
      Returns:
      The current status of the cluster node if it is one of the awaited statuses, null (as first element of the triple) otherwise. Additionally, the triple will always contain the time of the last status update and the time since when this node is running.
      Throws:
      InterruptedException - If the current thread is interrupted while waiting for one of the designated statuses, an InterruptedException will be thrown.
      AbortServiceException - If there are non-recoverable problems with the cluster especially when bootstrapping, an AbortServiceException will be thrown.