Package org.apache.cassandra.schema

Class OfflineSchemaUpdateHandler

java.lang.Object

org.apache.cassandra.schema.OfflineSchemaUpdateHandler

All Implemented Interfaces:

SchemaUpdateHandler

public class OfflineSchemaUpdateHandler
extends java.lang.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 Summary

Constructors

Constructor	Description
OfflineSchemaUpdateHandler(java.util.function.BiConsumer<SchemaTransformation.SchemaTransformationResult,java.lang.Boolean> updateCallback)

Method Summary

Modifier and Type	Method	Description
SchemaTransformation.SchemaTransformationResult	apply(SchemaTransformation transformation, boolean local)	Applies schema transformation in the underlying storage and synchronizes with other nodes.
Awaitable	clear()	Marks the local schema to be cleared and refreshed.
void	reset(boolean local)	Resets the schema either by reloading data from the local storage or from the other nodes.
void	start()	Starts actively synchronizing schema with the rest of the cluster.
boolean	waitUntilReady(java.time.Duration timeout)	Waits until the schema update handler is ready and returns the result.

Methods inherited from class java.lang.Object

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

Constructor Detail

OfflineSchemaUpdateHandler

public OfflineSchemaUpdateHandler(java.util.function.BiConsumer<SchemaTransformation.SchemaTransformationResult,java.lang.Boolean> updateCallback)

Method Detail

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(java.time.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