org.virtualrepository

Interface VirtualRepository

All Superinterfaces:

Iterable<Asset>

All Known Implementing Classes:

Repository

public interface VirtualRepository
extends Iterable<Asset>

A repository virtually comprised of data assets available through a number of underlying repository services .

Clients may:

• discover all the assets of given types available through the repository services (cf. discover(AssetType...)). Asset descriptions can be iterated over or looked up up by identifier (cf. lookup(String));
• retrieve the content of discovered assets (cf. retrieve(Asset, Class));
• publish new assets in one of the repository services (cf. publish(Asset, Object)).

Note that repository services may be remotely accessible, and typically will be. Most of the operations of a virtual repository may then trigger network interactions, as specified in their documentation.

Author:

Fabio Simeoni

See Also:

Asset, AssetType, RepositoryService

Method Summary

Methods

Modifier and Type	Method and Description
int	discover(AssetType... types) Discovers all the assets of given AssetTypes which are available through the underlying RepositoryServices, , using a default timeout.
int	discover(long timeout, AssetType... types) Discovers all the assets of given AssetTypes which are available through the underlying RepositoryServices, using a given timeout.
Map<AssetType,List<Asset>>	lookup(AssetType... type) Returns all the Asset of given AssetTypes which have been previously discovered.
List<Asset>	lookup(AssetType type) Returns all the Asset of which AssetType that have been previously discovered.
Asset	lookup(String id) Returns an Asset previously discovered.
void	publish(Asset asset, Object content) Publishes a given Asset with the RepositoryService bound to the asset.
<A> A	retrieve(Asset asset, Class<A> api) Retrieves the content of a given Asset from the RepositoryService bound to the asset, under a given API.
Services	services() Returns the RepositoryServices underlying this repository.
void	shutdown() Closes this repository and releases its resources.
Collection<RepositoryService>	sinks(AssetType... types) Returns the RepositoryServices underlying this repository which can publish `Asset`s of at least one of given AssetTypes.
Collection<RepositoryService>	sources(AssetType... types) Returns the RepositoryServices underlying this repository which can retrieve `Asset`s of at least one of given AssetTypes.

Methods inherited from interface java.lang.Iterable

iterator

Method Detail

services

Services services()

Returns the RepositoryServices underlying this repository.

Returns:

sinks

Collection<RepositoryService> sinks(AssetType... types)

Returns the RepositoryServices underlying this repository which can publish `Asset`s of at least one of given AssetTypes.

Returns:

the services which can publish `Asset`s of at least one of given AssetTypes

sources

Collection<RepositoryService> sources(AssetType... types)

Returns the RepositoryServices underlying this repository which can retrieve `Asset`s of at least one of given AssetTypes.

Returns:

the services which can retrieve `Asset`s of at least one of given AssetTypes

discover

int discover(AssetType... types)

Discovers all the assets of given AssetTypes which are available through the underlying RepositoryServices, , using a default timeout.

Parameters:

types - the asset types

Returns:

the number of (newly) discovered assets

See Also:

discover(long, AssetType...)

discover

int discover(long timeout,
           AssetType... types)

Discovers all the assets of given AssetTypes which are available through the underlying RepositoryServices, using a given timeout.

Discovery may involve networked interactions with repository services, and typically will. Failures that occur when interacting with given repository services are silently tolerated. The interactions do not imply the transfer of asset content, however, only content descriptions.

This method may be invoked multiple times in the lifetime of this repository, typically to discover new assets that may have become available through the repository services. In this case, discovering an asset overwrites any existing description of an asset with the same identifier.

Parameters:

types - the asset types

Returns:

the number of (newly) discovered assets

lookup

Asset lookup(String id)

Returns an Asset previously discovered.

This is a local operation and does not trigger network interactions.

Parameters:

name - the asset identifier

Returns:

the asset

Throws:

IllegalStateException - if an asset with the given identifier was not ingested in this repository

lookup

List<Asset> lookup(AssetType type)

Returns all the Asset of which AssetType that have been previously discovered.

This is a local operation and does not trigger network interactions.

Parameters:

the - AssetType

Returns:

the assets of the given AssetType

lookup

Map<AssetType,List<Asset>> lookup(AssetType... type)

Returns all the Asset of given AssetTypes which have been previously discovered.

This is a local operation and does not trigger network interactions.

Parameters:

the - AssetTypes

Returns:

the assets of the given AssetTypes

retrieve

<A> A retrieve(Asset asset,
             Class<A> api)

Retrieves the content of a given Asset from the RepositoryService bound to the asset, under a given API.

Retrieval may involve networked interactions with the repository service, and typically will. Failures are reported as unchecked exceptions.

Parameters:

asset - the asset

api - the API

Returns:

the content of the asset

Throws:

IllegalArgumentException - is the asset has no associated service

IllegalStateException - if the content of the asset cannot be retrieved with the given API

publish

void publish(Asset asset,
           Object content)

Publishes a given Asset with the RepositoryService bound to the asset.

Publication may involve networked interactions with the repository service, and typically will. Failures are reported as unchecked exceptions.

Parameters:

asset - the asset

content - the content of the asset

Throws:

IllegalArgumentException - is the asset has no associated service

IllegalStateException - if the asset cannot be published under the API of the content provided

shutdown

void shutdown()

Closes this repository and releases its resources.