org.opendaylight.vtn.manager.internal.util.tx

Class AbstractTxTask<T>

java.lang.Object

org.opendaylight.vtn.manager.internal.util.tx.AbstractTxTask<T>

Type Parameters:

T - The type of the object to be returned by the task.

All Implemented Interfaces:

TxTask<T>

Direct Known Subclasses:

AbstractRpcTask, AddedFlowStats, AddFlowStatsTask, ClearFlowConditionTask, ClearPathMapTask, ClearPathPolicyTask, CompositeTxTask, DeleteFlowTxTask, PutFlowTxTask, RollbackTxTask, TxEvent

public abstract class AbstractTxTask<T>
extends Object
implements TxTask<T>

An abstract simple implementation of TxTask.

This class attempt to repeat the transaction at most 5 times if the transaction fails due to data conflict.

Constructor Summary

Constructors

Constructor and Description
AbstractTxTask()

Method Summary

Modifier and Type	Method and Description
void	addBackgroundTask(VTNFuture<?> future) Associate the given future with this task.
protected abstract T	execute(TxContext ctx) Modify the MD-SAL datastore using the given transaction.
T	execute(TxContext ctx, int attempts) Modify the MD-SAL datastore using the given transaction.
List<VTNFuture<?>>	getBackgroundTasks() Return an immutable list of VTNFuture instances associated with background tasks started by the MD-SAL transaction task.
protected int	getMaxRetry() Return the number of times for retrying transaction.
void	onFailure(VTNManagerProvider provider, Throwable t) Invoked when the task has failed.
void	onSuccess(VTNManagerProvider provider, T result) Invoked when the task has completed successfully.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.opendaylight.vtn.manager.internal.TxTask

isAsync, needErrorLog

Constructor Detail

AbstractTxTask

public AbstractTxTask()

Method Detail

execute

protected abstract T execute(TxContext ctx)
                      throws VTNException

Modify the MD-SAL datastore using the given transaction.

Note that this method may be called more than once when a MD-SAL datastore transaction is aborted due to data conflict.

Parameters:

ctx - A runtime context for transaction task.

Returns:

Result of this task.

Throws:

VTNException - An error occurred.

getMaxRetry

protected int getMaxRetry()

Return the number of times for retrying transaction.

This method can be used to control the number of transaction retry when the transaction failed due to data confliction.

This method in this class returns MAX_RETRY. Subclass can override this method to change the number of times for retrying transaction.

Returns:

The number of times for retrying transaction.

execute

public final T execute(TxContext ctx,
                       int attempts)
                throws VTNException

Modify the MD-SAL datastore using the given transaction.

Note that this method may be called more than once when a MD-SAL datastore transaction is aborted due to data conflict.

Specified by:

execute in interface TxTask<T>

Parameters:

ctx - A runtime context for transaction task.

attempts - The number of calls of this method. 0 is passed for the first call.

Returns:

Result of this task.

Throws:

VTNException - An error occurred.

onSuccess

public void onSuccess(VTNManagerProvider provider,
                      T result)

Invoked when the task has completed successfully.

This method of this class does nothing.

Specified by:

onSuccess in interface TxTask<T>

Parameters:

provider - VTN Manager provider service.

result - An object returned by execute(TxContext, int).

onFailure

public void onFailure(VTNManagerProvider provider,
                      Throwable t)

Invoked when the task has failed.

This method of this class does nothing.

Specified by:

onFailure in interface TxTask<T>

Parameters:

provider - VTN Manager provider service.

t - A Throwable thrown by the task.

getBackgroundTasks

public final List<VTNFuture<?>> getBackgroundTasks()

Return an immutable list of VTNFuture instances associated with background tasks started by the MD-SAL transaction task.

Specified by:

getBackgroundTasks in interface TxTask<T>

Returns:

An immutable list of VTNFuture instances. An empty list is returned if no background task has started or this task does not complete yet. Note that this method must not return null.

addBackgroundTask

public final void addBackgroundTask(VTNFuture<?> future)

Associate the given future with this task.

The task associated with the given future will be treated as a background task associated with this task.

Specified by:

addBackgroundTask in interface TxTask<T>

Parameters:

future - A VTNFuture instance associated with background task.