Package org.apache.cassandra.schema

Class OfflineSchemaUpdateHandler

java.lang.Object
org.apache.cassandra.schema.OfflineSchemaUpdateHandler
All Implemented Interfaces:
SchemaUpdateHandler
public class OfflineSchemaUpdateHandler extends Object implements SchemaUpdateHandler
Update handler which works only in memory. It does not load or save the schema anywhere. It is used in client mode applications.

  • Constructor Details

  • Method Details

    • start

      public void start()
      Description copied from interface: SchemaUpdateHandler
      Starts actively synchronizing schema with the rest of the cluster. It is called in the very beginning of the node startup. It is not expected to block - to await for the startup completion we have another method SchemaUpdateHandler.waitUntilReady(Duration).
      Specified by:
      start in interface SchemaUpdateHandler

    • waitUntilReady

      public boolean waitUntilReady(Duration timeout)
      Description copied from interface: SchemaUpdateHandler
      Waits until the schema update handler is ready and returns the result. If the method returns false it means that readiness could not be achieved within the specified period of time. The method can be used just to check if schema is ready by passing Duration.ZERO as the timeout - in such case it returns immediately.
      Specified by:
      waitUntilReady in interface SchemaUpdateHandler
      Parameters:
      timeout - the maximum time to wait for schema readiness
      Returns:
      whether readiness is achieved

    • apply

      public SchemaTransformation.SchemaTransformationResult apply(SchemaTransformation transformation, boolean local)
      Description copied from interface: SchemaUpdateHandler
      Applies schema transformation in the underlying storage and synchronizes with other nodes.
      Specified by:
      apply in interface SchemaUpdateHandler
      Parameters:
      transformation - schema transformation to be performed
      local - if true, the caller does not require synchronizing schema with other nodes - in practise local is used only in some tests
      Returns:
      transformation result

    • reset

      public void reset(boolean local)
      Description copied from interface: SchemaUpdateHandler
      Resets the schema either by reloading data from the local storage or from the other nodes. Once the schema is refreshed, the callbacks provided in the factory method are executed, and the updated schema version is announced.
      Specified by:
      reset in interface SchemaUpdateHandler
      Parameters:
      local - whether we should reset with locally stored schema or fetch the schema from other nodes

    • clear

      public Awaitable clear()
      Description copied from interface: SchemaUpdateHandler
      Marks the local schema to be cleared and refreshed. Since calling this method, the update handler tries to obtain a fresh schema definition from a remote source. Once the schema definition is received, the local schema is replaced (instead of being merged which usually happens when the update is received).

      The returned awaitable is fulfilled when the schema is received and applied.

      Specified by:
      clear in interface SchemaUpdateHandler