org.kitesdk.data.spi

Interface MetadataProvider

All Known Implementing Classes:

AbstractMetadataProvider

@NotThreadSafe
public interface MetadataProvider

A service provider interface for metadata system plugins.

Implementations of MetadataProvider are typically not thread-safe; that is, the behavior when accessing a single instance from multiple threads is undefined.

Method Summary

Methods

Modifier and Type	Method and Description
DatasetDescriptor	create(String namespace, String name, DatasetDescriptor descriptor) Create a DatasetDescriptor for the dataset named name.
Collection<String>	datasets(String namespace) List the dataset names managed by this MetadataProvider in the given namespace.
boolean	delete(String namespace, String name) Delete all metadata associated with the dataset named name.
boolean	exists(String namespace, String name) Checks if there is a DatasetDescriptor for the dataset named name.
DatasetDescriptor	load(String namespace, String name) Load the dataset descriptor for the dataset name.
Collection<String>	namespaces() List the namespaces for Datasets managed by this MetadataProvider.
DatasetDescriptor	update(String namespace, String name, DatasetDescriptor descriptor) Update a DatasetDescriptor for the dataset named name.

Method Detail

load

DatasetDescriptor load(String namespace,
                     String name)

Load the dataset descriptor for the dataset name.

Parameters:

namespace - A namespace, or logical group name, for the dataset.

name - The name of an existing dataset.

Returns:

A dataset descriptor.

Throws:

DatasetNotFoundException - If there is no descriptor for name

DatasetException - If the dataset doesn't exist or the descriptor can not be loaded.

Since:

0.16.0

create

DatasetDescriptor create(String namespace,
                       String name,
                       DatasetDescriptor descriptor)

Create a DatasetDescriptor for the dataset named name. The descriptor will be stored for the named data set in this provider's metadata store. It is illegal to create more than one descriptor for a named data set, and an exception will be thrown.

Parameters:

namespace - A namespace, or logical group name, for the dataset.

name - The name of a dataset.

descriptor - A dataset descriptor.

Returns:

The descriptor as persisted to the Metadata store.

Throws:

DatasetExistsException - If a DatasetDescriptor already exists for name

DatasetException - If the DatasetDescriptor can not be saved

Since:

0.16.0

update

DatasetDescriptor update(String namespace,
                       String name,
                       DatasetDescriptor descriptor)

Update a DatasetDescriptor for the dataset named name. The new descriptor will be stored for the named data set in this provider's metadata store, replacing the previous descriptor. The named dataset must already exist or an error will be thrown. This method is optional.

Parameters:

namespace - A namespace, or logical group name, for the dataset.

name - The name of a dataset.

descriptor - A dataset descriptor.

Returns:

The descriptor as persisted to the Metadata store.

Throws:

DatasetNotFoundException - If there is no descriptor for name

UnsupportedOperationException - If descriptor updates are not supported by the implementation.

DatasetException - If the dataset descriptor can not be updated.

Since:

0.16.0

delete

boolean delete(String namespace,
             String name)

Delete all metadata associated with the dataset named name. After this method is called, there will be no DatasetDescriptor stored for the given name, unless an exception has been thrown. If metadata was removed, this method will return true. If there was no DatasetDescriptor corresponding to the given name, then this method will not make any changes and will return false.

Parameters:

namespace - A namespace, or logical group name, for the dataset.

name - The name of a dataset.

Returns:

true if the metadata is successfully deleted, false if no action was taken.

Throws:

DatasetException - If the dataset metadata exists but can not be deleted.

Since:

0.16.0

exists

boolean exists(String namespace,
             String name)

Checks if there is a DatasetDescriptor for the dataset named name.

Parameters:

namespace - A namespace, or logical group name, for the dataset.

name - a Dataset name to check the existence of

Returns:

true if name exists, false otherwise

Throws:

DatasetException

Since:

0.16.0

namespaces

Collection<String> namespaces()

List the namespaces for Datasets managed by this MetadataProvider. If there is not at least one Dataset, an empty list will be returned.

Returns:

a Collection of namespace names (Strings)

Throws:

DatasetException

Since:

0.16.0

datasets

Collection<String> datasets(String namespace)

List the dataset names managed by this MetadataProvider in the given namespace. If there is not at least one Dataset in the namespace or if the namespace does not exist, an empty list will be returned.

Returns:

a Collection of Dataset names (Strings)

Throws:

DatasetException

Since:

0.16.0