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

java.lang.Object
  |
  +--com.hp.hpl.mesa.rdf.jena.common.ModelCom
        |
        +--com.hp.hpl.mesa.rdf.jena.rdb.ModelRDB

All Implemented Interfaces:

Model, ModelCon, ModelI, RDFReaderF, RDFWriterF

public class ModelRDB

extends ModelCom

implements Model, ModelI

This implementation of the Model interface uses a relational database to hold the model statements. This provides persistence, transactions and scaling at the expense of performance. It doesn't provide query support since the jena query interface is currently procedural rather than declarative.

Different SQL dialects and different table layout structures are supported by delegating all database access to a separate IRDBSpec implementation.

The constructor will open the default model on a jdbc url whereas a variety of static factory methods are available for creating and reopening database.

Version:

$Revision: 1.3 $ on $Date: 2001/12/06 11:55:09 $

Author:

Dave Reynolds

Constructor Summary

ModelRDB(IDBConnection dbcon)
Return the default model from the specified database.

Method Summary

Model	abort() Abort the current transaction and abandon any changes in progress.
Model	begin() Begin a new transation.
void	close() Close the Model and free up resources held.
Model	commit() Commit the current transaction.
Property	convert(Property p) Convert a property to a database implementation
RDFNode	convert(RDFNode n) Convert a node (property, resource or literal) to a database implementation
Resource	convert(Resource r) Convert a resource to a database implementation
static ModelRDB	create(IDBConnection dbcon, java.lang.String layoutType, java.lang.String databaseType) Create a new database suitable for storing RDF data.
IConstraints	createConstraints() Create a constraint object appropriate for this type of database layout
static ModelRDB	createModel(IDBConnection dbcon, java.lang.String name) Create a new model on an existing, preformatted database.
Model	difference(Model model) Create a new model containing all the statements in this model which are not in another.
IDBID	getDBID() Return the database index id for this model.
StoreRDB	getStore() Return the store which underpins this model
boolean	independent() Determine whether this model is independent.
Model	intersection(Model model) Create a new model containing all the statements which are in both this model and another.
static java.util.Iterator	listModels(IDBConnection dbcon) List the name of all models stored in the database
StmtIterator	listStatements(IConstraints constraints) List all the statements in the given moddel which make the given set of constraints (a constraint set can be obtained using createConstraints()).
static ModelRDB	open(IDBConnection dbcon) Open an existing rdf database.
static ModelRDB	open(IDBConnection dbcon, java.lang.String name) Open an existing rdf database.
Model	query(Selector selector) Create a new model containing the statements matching a query.
boolean	supportsSetOperations() Determine whether this model supports set operations.
boolean	supportsTransactions() Determine whether this model supports transactions.
Model	union(Model model) Create a new model containing all the statements in this model together with all of those in another given model.

Methods inherited from class com.hp.hpl.mesa.rdf.jena.common.ModelCom

add, add, add, add, add, add, add, add, add, add, add, add, add, add, containerContains, containerIndexOf, containerSize, contains, contains, contains, contains, contains, contains, contains, contains, contains, contains, contains, containsAll, containsAll, containsAny, containsAny, createAlt, createAlt, createBag, createBag, createLiteral, createLiteral, createLiteral, createLiteral, createLiteral, createLiteral, createLiteral, createLiteral, createLiteral, createProperty, createProperty, createResource, createResource, createResource, createResource, createResource, createResource, createSeq, createSeq, createStatement, createStatement, createStatement, createStatement, createStatement, createStatement, createStatement, createStatement, createStatement, createStatement, createStatement, equals, getAlt, getAlt, getBag, getBag, getProperty, getProperty, getProperty, getReader, getReader, getResource, getResource, getSeq, getSeq, getWriter, getWriter, isReified, listContainerMembers, listNameSpaces, listObjects, listObjectsOfProperty, listObjectsOfProperty, listReifiedStatements, listStatements, listStatements, listSubjects, listSubjectsWithProperty, listSubjectsWithProperty, listSubjectsWithProperty, listSubjectsWithProperty, listSubjectsWithProperty, listSubjectsWithProperty, listSubjectsWithProperty, listSubjectsWithProperty, listSubjectsWithProperty, listSubjectsWithProperty, read, read, read, read, remove, remove, remove, setReaderClassName, setWriterClassName, size, write, write, write

Methods inherited from class java.lang.Object

getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface com.hp.hpl.mesa.rdf.jena.model.Model

add, add, add, contains, contains, contains, containsAll, containsAll, containsAny, containsAny, createLiteral, createLiteral, createProperty, createResource, createResource, createStatement, equals, getProperty, getProperty, getResource, isReified, listNameSpaces, listObjects, listObjectsOfProperty, listObjectsOfProperty, listReifiedStatements, listStatements, listStatements, listSubjects, listSubjectsWithProperty, listSubjectsWithProperty, read, read, read, read, remove, size, write, write, write

Methods inherited from interface com.hp.hpl.mesa.rdf.jena.model.ModelCon

add, add, add, add, add, add, add, add, add, add, add, contains, contains, contains, contains, contains, contains, contains, contains, createAlt, createAlt, createBag, createBag, createLiteral, createLiteral, createLiteral, createLiteral, createLiteral, createLiteral, createLiteral, createProperty, createResource, createResource, createResource, createResource, createSeq, createSeq, createStatement, createStatement, createStatement, createStatement, createStatement, createStatement, createStatement, createStatement, createStatement, createStatement, getAlt, getAlt, getBag, getBag, getProperty, getResource, getSeq, getSeq, listSubjectsWithProperty, listSubjectsWithProperty, listSubjectsWithProperty, listSubjectsWithProperty, listSubjectsWithProperty, listSubjectsWithProperty, listSubjectsWithProperty, listSubjectsWithProperty, remove, remove

Methods inherited from interface com.hp.hpl.mesa.rdf.jena.model.RDFReaderF

getReader, getReader, setReaderClassName

Methods inherited from interface com.hp.hpl.mesa.rdf.jena.model.RDFWriterF

getWriter, getWriter, setWriterClassName

Methods inherited from interface com.hp.hpl.mesa.rdf.jena.common.ModelI

containerContains, containerIndexOf, containerSize, listContainerMembers

Constructor Detail

ModelRDB

public ModelRDB(IDBConnection dbcon)
         throws RDFRDBException

Return the default model from the specified database. If the database does not appear to be formated it formats it and creates an empty default model.

Parameters:

dbcon - a DBConnectionI specifying the database connection

Throws:

RDFRDBException - if the database cannot be opened

Method Detail

open

public static ModelRDB open(IDBConnection dbcon,
                            java.lang.String name)
                     throws RDFRDBException

Open an existing rdf database. The layout and datatype type information will be dynamically loaded from the database. Will throw an RDFRDBException if the database layout does not support multiple models or if the database does not seem to formated.

Parameters:

dbcon - a DBConnectionI specifying the database connection

name - the name of the RDF model to open, some database layouts support multiple models in a single database

open

public static ModelRDB open(IDBConnection dbcon)
                     throws RDFRDBException

Open an existing rdf database. The layout and datatype type information will be dynamically loaded from the database. If the database supports more than one model then the "default" model will be opended.

Parameters:

dbcon - a DBConnectionI specifying the database connection

createModel

public static ModelRDB createModel(IDBConnection dbcon,
                                   java.lang.String name)
                            throws RDFRDBException

Create a new model on an existing, preformatted database. Will throw an RDFRDBException if the database layout does not support multiple models or if the database does not seem to formated.

Parameters:

dbcon - a DBConnectionI specifying the database connection

name - the name to give the newly created model

listModels

public static java.util.Iterator listModels(IDBConnection dbcon)
                                     throws RDFRDBException

List the name of all models stored in the database

create

public static ModelRDB create(IDBConnection dbcon,
                              java.lang.String layoutType,
                              java.lang.String databaseType)
                       throws RDFRDBException

Create a new database suitable for storing RDF data. In fact the database has to exist since jdbc can't create an empty database from a vacuum but it can be empty and this call will format with appropriate tables and stored procedures.

The appropriate RDF-RDB driver to use is assumed to be the class Driver. If that can't be found it defaults to looking for a property file in /etc/Driver.config and using that to determine the driver class and parameters.

Parameters:

dbcon - a DBConnectionI specifying the database connection

layoutType - the name of the layout style to use. Currently one of: "Generic", "Hash", "MMGeneric", "MMHash", "Proc", "ThinProc" etc.

databaseType - the name of the database type. Currently one of: "Interbase" "Postgresql" etc. This may seem a little redundant given that the jdbc uri implicitly contains this information but there is no standard way of extracting this (esp. if the user connects via a bridge).

close

public void close()

Close the Model and free up resources held.

Not all implementations of Model require this method to be called. But some do, so in general its best to call it when done with the object, rather than leave it to the finalizer.

Specified by:

close in interface Model

Overrides:

close in class ModelCom

getStore

public StoreRDB getStore()

Return the store which underpins this model

getDBID

public IDBID getDBID()

Return the database index id for this model. This will be 0 unless the underlying database layout supports multiple models per database.

listStatements

public StmtIterator listStatements(IConstraints constraints)
                            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()).

createConstraints

public IConstraints createConstraints()

Create a constraint object appropriate for this type of database layout

convert

public Resource convert(Resource r)
                 throws RDFException

Convert a resource to a database implementation

Specified by:

convert in interface ModelI

Overrides:

convert in class ModelCom

Following copied from interface: com.hp.hpl.mesa.rdf.jena.common.ModelI

Parameters:

r -

Returns:

the converted resource

Throws:

RDFException -

convert

public Property convert(Property p)
                 throws RDFException

Convert a property to a database implementation

Specified by:

convert in interface ModelI

Overrides:

convert in class ModelCom

Following copied from interface: com.hp.hpl.mesa.rdf.jena.common.ModelI

Parameters:

p -

Returns:

the converted property

Throws:

RDFException -

convert

public RDFNode convert(RDFNode n)
                throws RDFException

Convert a node (property, resource or literal) to a database implementation

Specified by:

convert in interface ModelI

Overrides:

convert in class ModelCom

Following copied from interface: com.hp.hpl.mesa.rdf.jena.common.ModelI

Parameters:

n -

Returns:

the converted node

Throws:

RDFException -

begin

public Model begin()
            throws RDFException

Begin a new transation.

All changes made to a model within a transaction, will either be made, or none of them will be made.

Specified by:

begin in interface Model

Overrides:

begin in class ModelCom

Returns:

this model to enable cascading.

Throws:

RDFException - Generic RDF Exception

abort

public Model abort()
            throws RDFException

Abort the current transaction and abandon any changes in progress.

Specified by:

abort in interface Model

Overrides:

abort in class ModelCom

Returns:

this model to enable cascading.

Throws:

RDFException - Generic RDF Exception

commit

public Model commit()
             throws RDFException

Commit the current transaction.

Specified by:

commit in interface Model

Overrides:

commit in class ModelCom

Returns:

this model to enable cascading.

Throws:

RDFException - Generic RDF Exception

independent

public boolean independent()

Determine whether this model is independent.

For efficiency reasons, some implementations may create models which which are dependent on others, i.e. a change in one model may cause a change in another. If this is the case this method will return false, otherwise it will return true.

Specified by:

independent in interface Model

Overrides:

independent in class ModelCom

Returns:

true if this model is indepdent of others

supportsTransactions

public boolean supportsTransactions()

Determine whether this model supports transactions.

Specified by:

supportsTransactions in interface Model

Returns:

true if this model supports transactions.

supportsSetOperations

public boolean supportsSetOperations()

Description copied from interface: Model

Determine whether this model supports set operations.

Specified by:

supportsSetOperations in interface Model

Following copied from interface: com.hp.hpl.mesa.rdf.jena.model.Model

Returns:

true if this model supports set operations.

query

public Model query(Selector selector)
            throws RDFException

Description copied from interface: Model

Create a new model containing the statements matching a query.

A statment is considered to match if the test method of s returns true when called on s.

Specified by:

query in interface Model

Following copied from interface: com.hp.hpl.mesa.rdf.jena.model.Model

Parameters:

s - A selector object.

Returns:

an iterator over the matching statements

Throws:

RDFException - Generic RDF exception.

union

public Model union(Model model)
            throws RDFException

Description copied from interface: Model

Create a new model containing all the statements in this model together with all of those in another given model.

Specified by:

union in interface Model

Following copied from interface: com.hp.hpl.mesa.rdf.jena.model.Model

Parameters:

model - The other model whose statements are to be included.

Returns:

A new model containing all the statements that are in either model

Throws:

RDFException - Generic RDF Exception

intersection

public Model intersection(Model model)
                   throws RDFException

Description copied from interface: Model

Create a new model containing all the statements which are in both this model and another. As models are sets of statements, a statement contained in both models will only appear once in the resulting model.

Specified by:

intersection in interface Model

Following copied from interface: com.hp.hpl.mesa.rdf.jena.model.Model

Parameters:

model - The other model.

Returns:

A new model containing all the statements that are in both models.

Throws:

RDFException - Generic RDF Exception

difference

public Model difference(Model model)
                 throws RDFException

Description copied from interface: Model

Create a new model containing all the statements in this model which are not in another.

Specified by:

difference in interface Model

Following copied from interface: com.hp.hpl.mesa.rdf.jena.model.Model

Parameters:

model - the other model whose statements are to be excluded.

Returns:

a new model containing all the statements in this model that are not in the given model.

Throws:

RDFException - Generic RDF Exception