eu.fbk.knowledgestore.datastore

Interface DataStore

All Superinterfaces:

AutoCloseable, Closeable, Component

All Known Implementing Classes:

CachingDataStore, DataStoreElastic, ForwardingDataStore, HBaseDataStore, LoggingDataStore, MemoryDataStore, MySQLDataStore, SolrDataStore, SynchronizedDataStore, TripleDataStore

public interface DataStore
extends Component

A persistent storage component for resource, mention, entity, axiom and context records.

A DataStore component abstracts the access to a storage system for resources, mentions, entities and contexts (the types listed in SUPPORTED_TYPES). Access to such a storage system can occur only in the scope of a transaction, which can either be read-only or read/write, identifies a unit of work and provides atomicity, isolation and durability guarantees. Note that a DataStore obeys the general contract and lifecycle of Component. In particular, note that a DataStore must be thread safe, even if the produced DataTransaction are not required to be so.

Field Summary

Fields

Modifier and Type	Field and Description
static Set<org.openrdf.model.URI>	SUPPORTED_TYPES The types of records that can be stored in a DataStore.

Method Summary

Modifier and Type	Method and Description
DataTransaction	begin(boolean readOnly) Begins a new read-only / read-write DataStore transaction.

Methods inherited from interface eu.fbk.knowledgestore.runtime.Component

close, init

Field Detail

SUPPORTED_TYPES

static final Set<org.openrdf.model.URI> SUPPORTED_TYPES

The types of records that can be stored in a DataStore.

Method Detail

begin

DataTransaction begin(boolean readOnly)
               throws DataCorruptedException,
                      IOException,
                      IllegalStateException

Begins a new read-only / read-write DataStore transaction. All the accesses to a DataStore must occur in the scope of a transaction, that must be ended (possibly committing the modifications done) as soon as possible to allow improving throughput.

Parameters:

readOnly - true if the transaction is not allowed to modify the contents of the DataStore (this allows for optimizing accesses).

Returns:

the created transaction

Throws:

DataCorruptedException - in case a transaction cannot be started due to the DataStore persistent data being damaged or non-existing (this may trigger some external recovery procedure)

IOException - if another IO error occurs while starting the transaction

IllegalStateException - if the DataStore object has been already closed