com.bigdata.rdf.task

Class AbstractApiTask<T>

java.lang.Object

com.bigdata.rdf.task.AbstractApiTask<T>

All Implemented Interfaces:

IReadOnly, IApiTask<T>, Callable<T>

Direct Known Subclasses:

AbstractRestApiTask, CreateKBTask, DestroyKBTask

public abstract class AbstractApiTask<T>
extends Object
implements IApiTask<T>, IReadOnly

Base class for task-oriented concurrency. Directly derived classes are suitable for internal tasks (stored queries, stored procedures, etc) while REST API tasks are based on a specialized subclass that also provides for access to the HTTP request and response. CAUTION: Instances of this class that perform mutations MUST throw an exception if they do not want to join a commit group. Failure to follow this guideline can break the ACID contract.

Author:

Bryan Thompson

See Also:

Concurrent unisolated operations against multiple KBs

Field Summary

Fields

Modifier and Type	Field and Description
protected String	namespace The namespace of the target KB instance.
protected long	timestamp The timestamp of the view of that KB instance.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractApiTask(String namespace, long timestamp)
protected	AbstractApiTask(String namespace, long timestamp, boolean isGRSRequired)

Method Summary

Methods

Modifier and Type	Method and Description
protected BigdataSailRepositoryConnection	getConnection() Return a connection for the namespace.
IIndexManager	getIndexManager() Return the IIndexManager.
long	getMutationCount()
String	getNamespace() The namespace of the target KB instance.
protected BigdataSailRepositoryConnection	getQueryConnection() Return a connection transaction, which may be either read-only or support mutation depending on the timestamp associated with the task's view.
protected BigdataSailRepositoryConnection	getQueryConnection(String namespace, long timestamp) This version uses the namespace and timestamp provided by the caller.
long	getTimestamp() The timestamp of the view of that KB instance.
protected BigdataSail.BigdataSailConnection	getUnisolatedSailConnection()
boolean	isGRSRequired() Tasks that create or destroy locatable resources need to write on the global row store (GRS).
abstract boolean	isReadOnly() Return true iff the procedure asserts that it will not write on the index.
void	setIndexManager(IIndexManager indexManager) Invoked to inform the task of the index manager before it is executed.
static <T> FutureTask<T>	submitApiTask(IIndexManager indexManager, IApiTask<T> task) Submit a task and return a Future for that task.
String	toString()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.concurrent.Callable

call

Field Detail

namespace

protected final String namespace

The namespace of the target KB instance.

timestamp

protected final long timestamp

The timestamp of the view of that KB instance.

Constructor Detail

AbstractApiTask

protected AbstractApiTask(String namespace,
               long timestamp)

Parameters:

namespace - The namespace of the target KB instance.

timestamp - The timestamp of the view of that KB instance.

AbstractApiTask

protected AbstractApiTask(String namespace,
               long timestamp,
               boolean isGRSRequired)

Parameters:

namespace - The namespace of the target KB instance.

timestamp - The timestamp of the view of that KB instance.

isGRSRequired - True iff a lock must be obtain on the Global Row Store (GRS). For example, the GRS is required for create/destroy of a relation (triple/quad store, etc).

Method Detail

isReadOnly

public abstract boolean isReadOnly()

Description copied from interface: IReadOnly

Return true iff the procedure asserts that it will not write on the index. When true, the procedure may be run against a view of the index that is read-only or which allows concurrent processes to read on the same index object. When false the procedure will be run against a mutable view of the index (assuming that the procedure is executed in a context that has access to a mutable index view).

Specified by:

isReadOnly in interface IReadOnly

getNamespace

public final String getNamespace()

Description copied from interface: IApiTask

The namespace of the target KB instance.

Specified by:

getNamespace in interface IApiTask<T>

getTimestamp

public final long getTimestamp()

Description copied from interface: IApiTask

The timestamp of the view of that KB instance.

Specified by:

getTimestamp in interface IApiTask<T>

isGRSRequired

public boolean isGRSRequired()

Description copied from interface: IApiTask

Tasks that create or destroy locatable resources need to write on the global row store (GRS). Such tasks must specify this property. Note that the GRS lock will have the side-effect of serializing all such tasks that write on the GRS index.

Specified by:

isGRSRequired in interface IApiTask<T>

toString

public String toString()

Overrides:

toString in class Object

setIndexManager

public void setIndexManager(IIndexManager indexManager)

Description copied from interface: IApiTask

Invoked to inform the task of the index manager before it is executed.

Specified by:

setIndexManager in interface IApiTask<T>

Parameters:

indexManager - The index manager.

getIndexManager

public IIndexManager getIndexManager()

Description copied from interface: IApiTask

Return the IIndexManager.

Specified by:

getIndexManager in interface IApiTask<T>

Returns:

The index manager.

getQueryConnection

protected BigdataSailRepositoryConnection getQueryConnection()
                                                      throws org.openrdf.repository.RepositoryException

Return a connection transaction, which may be either read-only or support mutation depending on the timestamp associated with the task's view. When the timestamp is associated with a historical commit point, this will be a read-only connection. When it is associated with the ITx.UNISOLATED view or a read-write transaction, this will be a mutable connection.

This version uses the namespace and timestamp associated with the HTTP request.

Throws:

org.openrdf.repository.RepositoryException

DatasetNotFoundException

getQueryConnection

protected BigdataSailRepositoryConnection getQueryConnection(String namespace,
                                                 long timestamp)
                                                      throws org.openrdf.repository.RepositoryException

This version uses the namespace and timestamp provided by the caller.

Parameters:

namespace -

timestamp -

Returns:

Throws:

org.openrdf.repository.RepositoryException

DatasetNotFoundException

getUnisolatedSailConnection

protected BigdataSail.BigdataSailConnection getUnisolatedSailConnection()
                                                                 throws org.openrdf.sail.SailException,
                                                                        InterruptedException

Throws:

org.openrdf.sail.SailException

InterruptedException

getConnection

protected BigdataSailRepositoryConnection getConnection()
                                                 throws org.openrdf.sail.SailException,
                                                        org.openrdf.repository.RepositoryException

Return a connection for the namespace. If the task is associated with either a read/write transaction or an ITx.UNISOLATED view of the indices, the connection may be used to read or write on the namespace. Otherwise the connection will be read-only.

Returns:

The connection.

Throws:

org.openrdf.sail.SailException

org.openrdf.repository.RepositoryException

DatasetNotFoundException - if the specified namespace does not exist.

submitApiTask

public static <T> FutureTask<T> submitApiTask(IIndexManager indexManager,
                              IApiTask<T> task)

Submit a task and return a Future for that task. The task will be run on the appropriate executor service depending on the nature of the backing database and the view required by the task.

This method returns a Future. Remember to do Future.get() on the returned Future to await the group commit.

Parameters:

indexManager - The IndexManager.

task - The task.

Returns:

The Future for that task.

See Also:

HA doLocalAbort() should interrupt NSS requests and AbstractTasks , Concurrent unisolated operations against multiple KBs

getMutationCount

public long getMutationCount()