Package dev.getelements.elements.rt.transact

Interface ReadWriteTransaction

All Superinterfaces:

AutoCloseable, ReadOnlyTransaction

public interface ReadWriteTransaction
extends ReadOnlyTransaction

Defines a set of mutable transactional operations.

Nested Class Summary

Nested classes/interfaces inherited from interface dev.getelements.elements.rt.transact.ReadOnlyTransaction

ReadOnlyTransaction.Builder<TransactionT extends ReadOnlyTransaction>

Method Summary

Modifier and Type	Method	Description
void	commit()	Commits the ReadWriteTransaction to persistent storage.
void	createTask(TaskId taskId, long timestamp)	Schedules the supplied TaskId to the supplied timestamp.
void	deleteTask(TaskId taskId)	Deletes the TaskId from the datastore.
void	linkExistingResource(ResourceId sourceResourceId, Path destination)	Links an existing ResourceId to a new Path, throwing an instance of ResourceNotFoundException if the ResourceId is not known or throwing an instance of DuplicateException if the supplied Path exists.
void	linkNewResource(ResourceId resourceId, Path path)	Creates a link betweeen a Path and ResourceId, provided that neither already exist.
void	removeResource(ResourceId resourceId)	Removes the Resource with the supplied ResourceId and automatically removes any Path instances that point to that ResourceId.
List<ResourceId>	removeResources(Path path, int max)	Removes multiple ResourceIds associated with the supplied Path, if the associated ResourceId is linked by no other Paths, then this method will also delete the ResourceIds associated with ths Path.
void	rollback()	Rolls back the transaction, releasing any temporary resources associated with the ReadWriteTransaction.
WritableByteChannel	saveNewResource(Path path, ResourceId resourceId)	Opens a WritableByteChannel to a newly defined Resource with the following Path and ResourceId.
ResourceService.Unlink	unlinkPath(Path path)	Unlinks the supplied Path, if the associated ResourceId is linked by no other Paths, then this method will also delete the ResourceId associated with it.
WritableByteChannel	updateResource(ResourceId resourceId)	Opens a WritableByteChannel to a newly defined Resource with the ResourceId If the ResourceId is not found, then this must throw an instance of ResourceNotFoundException to indicate that the operation is not possible.

Methods inherited from interface dev.getelements.elements.rt.transact.ReadOnlyTransaction

check, close, exists, getNodeId, getResourceId, list, loadResourceContents

Method Details

saveNewResource

WritableByteChannel saveNewResource(Path path,
 ResourceId resourceId)
                             throws IOException

Opens a WritableByteChannel to a newly defined Resource with the following Path and ResourceId. If a Path is already occupied, or the ResourceId has already been added, then this throws an instance of DuplicateException.

Parameters:

path - the path to link with the new ResourceId

resourceId - the ResourceId of the newly inserted ResourceId

Returns:

a WritableByteChannel which must be closed by the calling code when finished.

Throws:

IOException - if an IOException prevented opening the WritableByteChannel

updateResource

WritableByteChannel updateResource(ResourceId resourceId)
                            throws IOException

Opens a WritableByteChannel to a newly defined Resource with the ResourceId If the ResourceId is not found, then this must throw an instance of ResourceNotFoundException to indicate that the operation is not possible. The supplied WritableByteChannel is only guaranteed to be valid for the life of the transaction which created it. It may still be possible to write after the transaction is closed. However, the behavior of which is not defined.

Parameters:

resourceId - the ResourceId of the existing ResourceId

Returns:

a WritableByteChannel which must be closed by the calling code when finished.

Throws:

IOException - if an IOException prevented opening the WritableByteChannel

ResourceNotFoundException - if no ResourceId matches

linkNewResource

void linkNewResource(ResourceId resourceId,
 Path path)

Creates a link betweeen a Path and ResourceId, provided that neither already exist. If either exist, then this will throw an instance of DuplicateException.

Parameters:

resourceId - the ResourceId of the newly added Resource

path - the Path to link to the ResourceId

linkExistingResource

void linkExistingResource(ResourceId sourceResourceId,
 Path destination)

Links an existing ResourceId to a new Path, throwing an instance of ResourceNotFoundException if the ResourceId is not known or throwing an instance of DuplicateException if the supplied Path exists.

Parameters:

sourceResourceId - the ResourceId which will be the source of the link

destination - the Path indicating the destination of the link

unlinkPath

ResourceService.Unlink unlinkPath(Path path)

Unlinks the supplied Path, if the associated ResourceId is linked by no other Paths, then this method will also delete the ResourceId associated with it. If there is not a resource for the supplied Path, then this method will throw an instance of ResourceNotFoundException. The supplied Path must not be a wildcard.

Parameters:

path - the Path to unlink

Returns:

an instance of ResourceService.Unlink indicating the result of the operation.

removeResource

void removeResource(ResourceId resourceId)

Removes the Resource with the supplied ResourceId and automatically removes any Path instances that point to that ResourceId. If no such ResourceId exists, then this method must throw an instance of ResourceNotFoundException.

Parameters:

resourceId - the ResourceId to remove

removeResources

List<ResourceId> removeResources(Path path,
 int max)

Removes multiple ResourceIds associated with the supplied Path, if the associated ResourceId is linked by no other Paths, then this method will also delete the ResourceIds associated with ths Path. If the Path is not a wildcard Path, then the returned Stream<ResourceId> will have, at most, a single value. If the Path is a wildcard Path, then the returned Stream<ResourceId> will have, at most, the value specified in this method. This method should never throw an instance of ResourceNotFoundException, but rather return an empty result if no Paths match.

Parameters:

path - the Path to unlink

Returns:

an instance of ResourceService.Unlink indicating the result of the operation.

deleteTask

void deleteTask(TaskId taskId)

Deletes the TaskId from the datastore.

Parameters:

taskId - the TaskId.

createTask

void createTask(TaskId taskId,
 long timestamp)

Schedules the supplied TaskId to the supplied timestamp.

Parameters:

taskId - the TaskId

timestamp - the timestamp.

rollback

void rollback()

Rolls back the transaction, releasing any temporary resources associated with the ReadWriteTransaction.

commit

void commit()

Commits the ReadWriteTransaction to persistent storage. Once this method returns then all staged changes will persist and can be visible to all new transactions.