org.exolab.castor.dtx

Class DTXEngine

java.lang.Object

org.exolab.castor.dtx.DTXEngine

public class DTXEngine
extends java.lang.Object

An OQL query engine for hitting JDO data sources and generating SAX events. It skips the intermediate Java class step used by e.g. Castor JDO. The engine uses the SQL and XML descriptions in an XML Schema file and a Castor JDO mapping file to determine how to map results of the query into SAX events.

Version:

$Revision: 5951 $ $Date: 2006-04-08 05:10:21 -0600 (Sat, 08 Apr 2006) $

Author:

Evan Prodromou

Field Summary

Fields

Modifier and Type	Field and Description
protected java.util.HashMap	_classMappings
protected java.sql.Connection	_conn
protected Database	_database
protected java.lang.String	_databaseURL
protected PersistenceFactory	_factory
protected org.xml.sax.DocumentHandler	_handler
protected Schema	_schema
protected java.lang.String	_schemaURL

Constructor Summary

Constructors

Constructor and Description
DTXEngine() Default constructor.
DTXEngine(java.lang.String databaseURL, java.lang.String schemaURL) Construct a DTXEngine for the given JDO mapping file and XML schema.

Method Summary

Modifier and Type	Method and Description
(package private) ClassMapping	getClassMapping(java.lang.String className)
(package private) java.sql.Connection	getConnection()
(package private) Database	getDatabase()
(package private) PersistenceFactory	getFactory()
(package private) Schema	getSchema()
DTXQuery	prepareQuery(java.lang.String oql) Prepare a new DTXQuery object, given an OQL string.
void	setDatabase(java.lang.String databaseURL) Sets the database options from a JDO database mapping file.
void	setDocumentHandler(org.xml.sax.DocumentHandler handler) Sets the default SAX document handler for this DTX engine.
void	setSchema(java.lang.String schemaURL) Sets the XML Schema to use.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

_handler

protected org.xml.sax.DocumentHandler _handler

_databaseURL

protected java.lang.String _databaseURL

_database

protected Database _database

_schemaURL

protected java.lang.String _schemaURL

_schema

protected Schema _schema

_classMappings

protected java.util.HashMap _classMappings

_conn

protected java.sql.Connection _conn

_factory

protected PersistenceFactory _factory

Constructor Detail

DTXEngine

public DTXEngine()

Default constructor.

DTXEngine

public DTXEngine(java.lang.String databaseURL,
                 java.lang.String schemaURL)
          throws DTXException

Construct a DTXEngine for the given JDO mapping file and XML schema.

Parameters:

databaseURL - URL string for JDO mapping file.

schemaURL - URL string for XML Schema file.

Throws:

DTXException

Method Detail

setSchema

public void setSchema(java.lang.String schemaURL)
               throws DTXException

Sets the XML Schema to use. Parses and prepares the Schema.

Parameters:

schemaURL - URL string for XML Schema file.

Throws:

DTXException

setDatabase

public void setDatabase(java.lang.String databaseURL)
                 throws DTXException

Sets the database options from a JDO database mapping file.

Parameters:

databaseURL - URL string for JDO database mapping file.

Throws:

DTXException

setDocumentHandler

public void setDocumentHandler(org.xml.sax.DocumentHandler handler)

Sets the default SAX document handler for this DTX engine. Individual queries will use this handler by default, but it can be overwritten on a per-query basis.

Parameters:

handler - A DocumentHandler to receive query results as SAX events.

prepareQuery

public DTXQuery prepareQuery(java.lang.String oql)
                      throws DTXException

Prepare a new DTXQuery object, given an OQL string. The syntax is currently limited only to SELECT statements that return a single object type (although multiple results will appear as multiple documents to the DocumentHandler).

Parameters:

oql - OQL string for the query.

Throws:

DTXException

getDatabase

Database getDatabase()

getSchema

Schema getSchema()

getFactory

PersistenceFactory getFactory()

getConnection

java.sql.Connection getConnection()
                           throws DTXException

Throws:

DTXException

getClassMapping

ClassMapping getClassMapping(java.lang.String className)