Package org.apache.hadoop.hdfs.server.namenode

Class BackupState

java.lang.Object

org.apache.hadoop.hdfs.server.namenode.ha.HAState

org.apache.hadoop.hdfs.server.namenode.BackupState

@Private
public class BackupState
extends HAState

Field Summary

Fields inherited from class org.apache.hadoop.hdfs.server.namenode.ha.HAState

state

Constructor Summary

Constructors

Constructor	Description
BackupState()

Method Summary

Modifier and Type	Method	Description
void	checkOperation(HAContext context, NameNode.OperationCategory op)	Check if an operation is supported in a given state.
void	enterState(HAContext context)	Method to be overridden by subclasses to perform steps necessary for entering a state.
void	exitState(HAContext context)	Method to be overridden by subclasses to perform steps necessary for exiting a state.
void	prepareToExitState(HAContext context)	Method to be overridden by subclasses to prepare to exit a state.
boolean	shouldPopulateReplQueues()

Methods inherited from class org.apache.hadoop.hdfs.server.namenode.ha.HAState

getLastHATransitionTime, getServiceState, prepareToEnterState, setState, setStateInternal, toString

Methods inherited from class java.lang.Object

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

Constructor Details

BackupState

public BackupState()

Method Details

checkOperation

public void checkOperation(HAContext context,
 NameNode.OperationCategory op)
                    throws org.apache.hadoop.ipc.StandbyException

Description copied from class: HAState

Check if an operation is supported in a given state.

Specified by:

checkOperation in class HAState

Parameters:

context - HA context

op - Type of the operation.

Throws:

org.apache.hadoop.ipc.StandbyException - if a given type of operation is not supported in standby state

shouldPopulateReplQueues

public boolean shouldPopulateReplQueues()

Specified by:

shouldPopulateReplQueues in class HAState

enterState

public void enterState(HAContext context)
                throws org.apache.hadoop.ha.ServiceFailedException

Description copied from class: HAState

Method to be overridden by subclasses to perform steps necessary for entering a state.

Specified by:

enterState in class HAState

Parameters:

context - HA context

Throws:

org.apache.hadoop.ha.ServiceFailedException - on failure to enter the state.

exitState

public void exitState(HAContext context)
               throws org.apache.hadoop.ha.ServiceFailedException

Description copied from class: HAState

Method to be overridden by subclasses to perform steps necessary for exiting a state.

Specified by:

exitState in class HAState

Parameters:

context - HA context

Throws:

org.apache.hadoop.ha.ServiceFailedException - on failure to enter the state.

prepareToExitState

public void prepareToExitState(HAContext context)
                        throws org.apache.hadoop.ha.ServiceFailedException

Description copied from class: HAState

Method to be overridden by subclasses to prepare to exit a state. This method is called without the context being locked. This is used by the standby state to cancel any checkpoints that are going on. It can also be used to check any preconditions for the state transition. This method should not make any destructive changes to the state (eg stopping threads) since HAState.prepareToEnterState(HAContext) may subsequently cancel the state transition.

Overrides:

prepareToExitState in class HAState

Parameters:

context - HA context

Throws:

org.apache.hadoop.ha.ServiceFailedException - on precondition failure