org.exolab.castor.jdo.engine

Class SQLEngine

java.lang.Object

org.exolab.castor.jdo.engine.SQLEngine

All Implemented Interfaces:

Persistence

public final class SQLEngine
extends Object
implements Persistence

The SQL engine performs persistence of one object type against one SQL database. It can only persist simple objects and extended relationships. An SQL engine is created for each object type represented by a database. When persisting, it requires a physical connection that maps to the SQL database and the transaction running on that database

Version:

$Revision: 8762 $ $Date: 2006-04-26 16:24:34 -0600 (Wed, 26 Apr 2006) $

Author:

Assaf Arkin, Thomas Yip, Bruce Snyder, Werner Guttmann, Ralf Joachim

Constructor Summary

Constructors

Constructor and Description
SQLEngine(ClassDescriptor clsDesc, PersistenceFactory factory)

Method Summary

Methods

Modifier and Type	Method and Description
Identity	create(Database database, Object conn, ProposedEntity entity, Identity identity) Creates a new object in persistence storage.
PersistenceQuery	createCall(String spCall, Class[] types)
PersistenceQuery	createQuery(QueryExpression query, Class[] types, AccessMode accessMode) Creates and returns a new query object.
SQLRelationLoader	createSQLRelationLoader(String manyTable, String[] idSQL, int[] idType, TypeConvertor[] idTo, TypeConvertor[] idFrom, String[] relatedIdSQL, int[] relatedIdType, TypeConvertor[] ridTo, TypeConvertor[] ridFrom)
void	delete(Object conn, Identity identity) Deletes the object from persistent storage, given the object' identity.
SQLColumnInfo[]	getColumnInfoForIdentities()
ClassDescriptor	getDescriptor() Used by OQLQuery to retrieve the class descriptor.
SQLEngine	getExtends()
QueryExpression	getFinder()
SQLFieldInfo[]	getInfo()
QueryExpression	getQueryExpression()
TableInfo	getTableInfo()
protected Object	idToJava(int index, Object object)
void	load(Object conn, ProposedEntity entity, Identity identity, AccessMode accessMode) Loads the object from persistence storage.
void	setExtends(SQLEngine engine) Mutator method for setting extends SQLEngine.
void	store(Object conn, Identity identity, ProposedEntity newentity, ProposedEntity oldentity) Stores the object in persistent storage, given the object fields and its identity.
protected Object	toJava(int field, int column, Object object)
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

SQLEngine

public SQLEngine(ClassDescriptor clsDesc,
         PersistenceFactory factory)
          throws MappingException

Throws:

MappingException

Method Detail

createSQLRelationLoader

public SQLRelationLoader createSQLRelationLoader(String manyTable,
                                        String[] idSQL,
                                        int[] idType,
                                        TypeConvertor[] idTo,
                                        TypeConvertor[] idFrom,
                                        String[] relatedIdSQL,
                                        int[] relatedIdType,
                                        TypeConvertor[] ridTo,
                                        TypeConvertor[] ridFrom)

Specified by:

createSQLRelationLoader in interface Persistence

getColumnInfoForIdentities

public SQLColumnInfo[] getColumnInfoForIdentities()

getInfo

public SQLFieldInfo[] getInfo()

setExtends

public void setExtends(SQLEngine engine)

Mutator method for setting extends SQLEngine.

Parameters:

engine -

getExtends

public SQLEngine getExtends()

getDescriptor

public ClassDescriptor getDescriptor()

Used by OQLQuery to retrieve the class descriptor.

Returns:

the JDO class descriptor.

createQuery

public PersistenceQuery createQuery(QueryExpression query,
                           Class[] types,
                           AccessMode accessMode)
                             throws QueryException

Description copied from interface: Persistence

Creates and returns a new query object. The query object is used to execute a query against persistent storage and fetch the results of the query. The query parameter types are specified prehand. If a particular parameter type is unknown, null may be used and type checking will defer to query execution.

Specified by:

createQuery in interface Persistence

Parameters:

query - The query expression

types - List of all parameter types, or null

Returns:

A new query object that can be executed

Throws:

QueryException - The query is invalid

createCall

public PersistenceQuery createCall(String spCall,
                          Class[] types)

getQueryExpression

public QueryExpression getQueryExpression()

getFinder

public QueryExpression getFinder()

getTableInfo

public TableInfo getTableInfo()

idToJava

protected Object idToJava(int index,
              Object object)

toJava

protected Object toJava(int field,
            int column,
            Object object)

create

public Identity create(Database database,
              Object conn,
              ProposedEntity entity,
              Identity identity)
                throws PersistenceException

Description copied from interface: Persistence

Creates a new object in persistence storage. Called for an object that was created during the transaction when the identity of that object is known. Creates a new record in persistence storage. Must detect an attempt to create an object with the same identity and must retain a lock on the object after creation. If the identity is null, an identity might be created and returned by this method.

Specified by:

create in interface Persistence

conn - An open connection

entity - The fields to store

identity - The object's identity

Returns:

The object's identity

Throws:

PersistenceException - An object with the same identity already exists in persistent storage or any other persistence error occured.

store

public void store(Object conn,
         Identity identity,
         ProposedEntity newentity,
         ProposedEntity oldentity)
           throws PersistenceException

Description copied from interface: Persistence

Stores the object in persistent storage, given the object fields and its identity. The object has been loaded before or has been created through a call to Persistence.create(org.exolab.castor.jdo.Database, java.lang.Object, org.castor.persist.ProposedEntity, org.exolab.castor.persist.spi.Identity). This method should detect whether the object has been modified in persistent storage since it was loaded. After this method returns all locks on the object must be retained until the transaction has completed. This method may return a new stamp to track further updates to the object.

If the object was not retrieved for exclusive access, this method will be asked to perform dirty checking prior to storing the object. The original argument will contains the object's original fields as retrieved in the transaction, and stamp the object's stamp returned from a successful call to Persistence.load(java.lang.Object, org.castor.persist.ProposedEntity, org.exolab.castor.persist.spi.Identity, org.exolab.castor.mapping.AccessMode). These arguments are null for objects retrieved with an exclusive lock.

Specified by:

store in interface Persistence

Parameters:

conn - An open connection

identity - The object's identity

newentity - The fields to store

oldentity - The original fields, or null

Throws:

PersistenceException - The object has been modified in persistence storage since it was last loaded or has been deleted from persitence storage or any other persistence error occored.

delete

public void delete(Object conn,
          Identity identity)
            throws PersistenceException

Description copied from interface: Persistence

Deletes the object from persistent storage, given the object' identity. The object has been loaded before or has been created through a call to Persistence.create(org.exolab.castor.jdo.Database, java.lang.Object, org.castor.persist.ProposedEntity, org.exolab.castor.persist.spi.Identity). After this method returns all locks on the object must be retained until the transaction has completed.

Specified by:

delete in interface Persistence

Parameters:

conn - An open connection

identity - The object's identity

Throws:

PersistenceException - A persistence error occured

load

public void load(Object conn,
        ProposedEntity entity,
        Identity identity,
        AccessMode accessMode)
          throws PersistenceException

Loads the object from persistence storage. This method will load the object fields from persistence storage based on the object's identity. This method may return a stamp which can be used at a later point to determine whether the copy of the object in persistence storage is newer than the cached copy (see store(java.lang.Object, org.exolab.castor.persist.spi.Identity, org.castor.persist.ProposedEntity, org.castor.persist.ProposedEntity)). If lock is true the object must be locked in persistence storage to prevent concurrent updates.

Specified by:

load in interface Persistence

Parameters:

conn - An open connection

entity - An Object[] to load field values into

identity - Identity of the object to load.

accessMode - The access mode (null equals shared)

Throws:

PersistenceException - A persistence error occured

toString

public String toString()

Overrides:

toString in class Object