com.hp.hpl.mesa.rdf.jena.rdb
Class DriverGenericGeneric

java.lang.Object
  |
  +--com.hp.hpl.mesa.rdf.jena.rdb.DriverGenericGeneric

All Implemented Interfaces:

IRDBDriver

Direct Known Subclasses:

DriverGenericAttribute, DriverGenericGenericProc, DriverGenericHash, DriverGenericMMGeneric, DriverGenericProc

public class DriverGenericGeneric

extends java.lang.Object

implements IRDBDriver

Base database driver for implementing ModelRDB and StoreRDB. Different drivers are needed for different databases and different layout schemes.

This driver is a base implemention from which database-specific drivers can inherit. It is not generic in the sense that it will work on any minimal SQL store and so should be treated as if it were an abstract class.

The SQL statements which implement each of the functions are loaded in a separate file etc/[layout]_[database].sql from the classpath. See SQLCache documentation for more information on the format of this file.

Version:

$Revision: 1.5 $ on $Date: 2002/03/01 14:25:13 $

Author:

Dave Reynolds

Field Summary

static java.lang.String

ANON_NAMESPACE Namesapce used to flag anonymous resources

Constructor Summary

DriverGenericGeneric()
Create a bare instance of the driver.

Method Summary

void	addStatement(Statement s, ModelRDB m) Register a statement in the database.
IDBID	allocateModelID(java.lang.String modelName) Allocate a new databaseID for a new model in the same database.
void	attachStore(StoreRDB store) Register a store as a user of this driver.
void	cleanDB() Remove all RDF information from a database.
void	close() Close the databse connection
IConstraints	createConstraints(ModelRDB model) Create a constraint object appropriate for this type of database layout
void	deleteStatement(Resource subject, Property predicate, RDFNode object, ModelRDB m) Delete the statements in the model which match the given subject, predicate object.
void	detachStore(StoreRDB store) Notify that a store is no longer using this driver.
void	formatDB() Initialise a database ready to store RDF tables.
java.sql.Connection	getConnection() Return the jdbc connection to the database, opening it if necessary
Literal	getLiteral(IDBID id) Fetch a literal just knowing its literal rdb-id.
IDBID	getLiteralID(Literal l) Return the database ID for the literal, if it exists
IDBID	getModelID(java.lang.String modelName) Return the databaseID for an existing named model within the database.
java.lang.String	getNamespace(IDBID nsid) Return the namespace string corresponding to a given namespace id.
Property	getProperty(IDBID id, ModelRDB m) Fetch a property just knowing its resource rdb-id.
Property	getProperty(java.lang.String uri, ModelRDB m) Fetch a property, knowing its uri.
Resource	getResource(IDBID id, ModelRDB m) Fetch a resource just knowing its resource rdb-id.
Resource	getResource(java.lang.String uri, ModelRDB m) Fetch a resource, knowing its uri.
IDBID	getResourceID(Resource resource) Lookup the unique ID for a resource.
SQLCache	getSQLCache() Return the SQLCache used for database commands.
void	hintPropertyTable(Property p) Hint to the store that the given property could be stored as an attribute table.
boolean	isDBFormatOK() Check that the database has a legal set of RDF tables.
boolean	isStatementPresent(Resource subject, Property predicate, RDFNode object, ModelRDB m) Check if a statement is in the database.
java.util.Iterator	listModels() List the names of all models in this database
ResultSetIterator	listNamespaces(ModelRDB m) List all namespaces referenced in the model
ResultSetIterator	listStatements(IConstraints constraints, ModelRDB m) List all the statements in the given moddel which make the given set of constraints (a constraint set can be obtained using createConstraints(com.hp.hpl.mesa.rdf.jena.rdb.ModelRDB)).
ResultSetIterator	listStatements(Resource subject, Property predicate, RDFNode object, ModelRDB m) List all the statements in the model which match the given subject, predicate object - each of which can be null (meaning wildcard).
ResultSetIterator	listSubjects(ModelRDB m) List all the subject resources in the model
void	loadDatabaseDriver() Force a load of the jdbc driver.
void	loadProperties(java.util.Properties props) Load a set of configuration parameters into the driver.
Resource	makeResource(IDBID id, java.lang.String localname, IDBID nsid, ModelRDB m) Re-create a resource from its local name and namespace identifier
void	saveProperties() Store the configuration parameters onto the database layout table in the attached database
void	setConnection(IDBConnection dbcon) Link an existing instance of the driver to a specific jdbc connection
boolean	supportsMultipleModels() Returns true of the database layout supports multiple RDF models in the same database.
java.lang.String	toString() Printable name for the driver configuration
IDBID	wrapDBID(java.lang.Object id) Convert the raw SQL object used to store a database identifier into a java object which meets the IDBID interface
java.lang.Object	wrapFlag(boolean flag) Wrap up a boolean flag as a object which the jdbc driver can assert into a boolean/short column

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

ANON_NAMESPACE

public static final java.lang.String ANON_NAMESPACE

Namesapce used to flag anonymous resources

Constructor Detail

DriverGenericGeneric

public DriverGenericGeneric()

Create a bare instance of the driver. It is not functional until a database connection has been supplied via setConnection.

Method Detail

setConnection

public void setConnection(IDBConnection dbcon)
                   throws RDFRDBException

Link an existing instance of the driver to a specific jdbc connection

Specified by:

setConnection in interface IRDBDriver

close

public void close()
           throws RDFRDBException

Close the databse connection

Specified by:

close in interface IRDBDriver

Throws:

RDFRDBException - if there is an access problem

getConnection

public java.sql.Connection getConnection()
                                  throws RDFRDBException

Return the jdbc connection to the database, opening it if necessary

Specified by:

getConnection in interface IRDBDriver

getSQLCache

public SQLCache getSQLCache()

Return the SQLCache used for database commands.

Specified by:

getSQLCache in interface IRDBDriver

isDBFormatOK

public boolean isDBFormatOK()
                     throws RDFRDBException

Check that the database has a legal set of RDF tables. This is not a full validation check simply a test for the existence of some key tables as evidence of at least attempted formatting.

Specified by:

isDBFormatOK in interface IRDBDriver

Returns:

true if the database seems to be legally formated.

Throws:

RDFRDBException - typtically due to internal programming errors, might trap and change to logging operations in the future.

formatDB

public void formatDB()
              throws RDFRDBException

Initialise a database ready to store RDF tables. This version uses a simple generic representation based a statement table and a resource table, equivalent to the edge-based method of XML storage.

Specified by:

formatDB in interface IRDBDriver

Throws:

RDFRDBException - typtically due to internal programming errors, might trap and change to logging operations in the future.

cleanDB

public void cleanDB()

Remove all RDF information from a database. This will only work if there are no other clients us the DB so is mostly to simplify testing that a practical tool. Partial DB config or cleaning can leave the DB in a strange state hence it will continue with each cleanup phase even if earlier phases have generated errors and erros are only logged, not propagated as exceptions.

Specified by:

cleanDB in interface IRDBDriver

loadProperties

public void loadProperties(java.util.Properties props)

Load a set of configuration parameters into the driver.

Specified by:

loadProperties in interface IRDBDriver

saveProperties

public void saveProperties()
                    throws java.sql.SQLException

Store the configuration parameters onto the database layout table in the attached database

toString

public java.lang.String toString()

Printable name for the driver configuration

Overrides:

toString in class java.lang.Object

attachStore

public void attachStore(StoreRDB store)

Register a store as a user of this driver. One driver can support multiple store instances.

Specified by:

attachStore in interface IRDBDriver

detachStore

public void detachStore(StoreRDB store)

Notify that a store is no longer using this driver.

Specified by:

detachStore in interface IRDBDriver

addStatement

public void addStatement(Statement s,
                         ModelRDB m)
                  throws RDFException

Register a statement in the database.

Specified by:

addStatement in interface IRDBDriver

Parameters:

subjId - database index of the subject entry

predId - database index of the predicate entry

objId - database index of the object entry

isLiteral - if the object is a literal rather than a resource

listSubjects

public ResultSetIterator listSubjects(ModelRDB m)
                               throws RDFRDBException

List all the subject resources in the model

Specified by:

listSubjects in interface IRDBDriver

Parameters:

m - the model whose subjects are to be listed

Returns:

iterator over Resource objects

listNamespaces

public ResultSetIterator listNamespaces(ModelRDB m)
                                 throws RDFRDBException

List all namespaces referenced in the model

Specified by:

listNamespaces in interface IRDBDriver

Returns:

iterator over Strings

listStatements

public ResultSetIterator listStatements(Resource subject,
                                        Property predicate,
                                        RDFNode object,
                                        ModelRDB m)
                                 throws RDFException

List all the statements in the model which match the given subject, predicate object - each of which can be null (meaning wildcard).

Specified by:

listStatements in interface IRDBDriver

isStatementPresent

public boolean isStatementPresent(Resource subject,
                                  Property predicate,
                                  RDFNode object,
                                  ModelRDB m)
                           throws RDFException

Check if a statement is in the database.

Specified by:

isStatementPresent in interface IRDBDriver

listStatements

public ResultSetIterator listStatements(IConstraints constraints,
                                        ModelRDB m)
                                 throws RDFException

List all the statements in the given moddel which make the given set of constraints (a constraint set can be obtained using createConstraints(com.hp.hpl.mesa.rdf.jena.rdb.ModelRDB)).

Specified by:

listStatements in interface IRDBDriver

createConstraints

public IConstraints createConstraints(ModelRDB model)

Create a constraint object appropriate for this type of database layout

Specified by:

createConstraints in interface IRDBDriver

deleteStatement

public void deleteStatement(Resource subject,
                            Property predicate,
                            RDFNode object,
                            ModelRDB m)
                     throws RDFException

Delete the statements in the model which match the given subject, predicate object.

Specified by:

deleteStatement in interface IRDBDriver

getResource

public Resource getResource(java.lang.String uri,
                            ModelRDB m)
                     throws RDFException

Fetch a resource, knowing its uri.

Specified by:

getResource in interface IRDBDriver

getProperty

public Property getProperty(java.lang.String uri,
                            ModelRDB m)
                     throws RDFException

Fetch a property, knowing its uri.

Specified by:

getProperty in interface IRDBDriver

supportsMultipleModels

public boolean supportsMultipleModels()

Returns true of the database layout supports multiple RDF models in the same database.

Specified by:

supportsMultipleModels in interface IRDBDriver

allocateModelID

public IDBID allocateModelID(java.lang.String modelName)
                      throws RDFRDBException

Allocate a new databaseID for a new model in the same database.

Specified by:

allocateModelID in interface IRDBDriver

getModelID

public IDBID getModelID(java.lang.String modelName)
                 throws RDFRDBException

Return the databaseID for an existing named model within the database. Throws RDFRDBException if the driver does not support multiple models per db.

Specified by:

getModelID in interface IRDBDriver

listModels

public java.util.Iterator listModels()
                              throws RDFRDBException

List the names of all models in this database

Specified by:

listModels in interface IRDBDriver

getNamespace

public java.lang.String getNamespace(IDBID nsid)
                              throws RDFRDBException

Return the namespace string corresponding to a given namespace id. Can be null if the ID can from a hash function and namespace isn't registered yet.

Specified by:

getNamespace in interface IRDBDriver

getLiteral

public Literal getLiteral(IDBID id)
                   throws RDFException

Fetch a literal just knowing its literal rdb-id. Can be null if the ID can from a hash function and literal isn't registered yet.

Specified by:

getLiteral in interface IRDBDriver

getLiteralID

public IDBID getLiteralID(Literal l)
                   throws RDFRDBException

Return the database ID for the literal, if it exists

Specified by:

getLiteralID in interface IRDBDriver

getResourceID

public IDBID getResourceID(Resource resource)
                    throws RDFException

Lookup the unique ID for a resource. Return null if it does not have one yet.

Specified by:

getResourceID in interface IRDBDriver

getResource

public Resource getResource(IDBID id,
                            ModelRDB m)
                     throws RDFException

Fetch a resource just knowing its resource rdb-id. Can be null if the ID can from a hash function and resource isn't registered yet.

Specified by:

getResource in interface IRDBDriver

getProperty

public Property getProperty(IDBID id,
                            ModelRDB m)
                     throws RDFException

Fetch a property just knowing its resource rdb-id. Can be null if the ID can from a hash function and resource isn't registered yet.

Specified by:

getProperty in interface IRDBDriver

wrapDBID

public IDBID wrapDBID(java.lang.Object id)
               throws RDFRDBException

Convert the raw SQL object used to store a database identifier into a java object which meets the IDBID interface

Specified by:

wrapDBID in interface IRDBDriver

wrapFlag

public java.lang.Object wrapFlag(boolean flag)

Wrap up a boolean flag as a object which the jdbc driver can assert into a boolean/short column

makeResource

public Resource makeResource(IDBID id,
                             java.lang.String localname,
                             IDBID nsid,
                             ModelRDB m)
                      throws RDFException

Re-create a resource from its local name and namespace identifier

Specified by:

makeResource in interface IRDBDriver

loadDatabaseDriver

public void loadDatabaseDriver()
                        throws RDFRDBException

Force a load of the jdbc driver.

Throws:

RDFRDBException - if the driver fails to load

hintPropertyTable

public void hintPropertyTable(Property p)
                       throws RDFException

Hint to the store that the given property could be stored as an attribute table.

Specified by:

hintPropertyTable in interface IRDBDriver