org.datanucleus.store.rdbms

Class RDBMSPersistenceHandler

java.lang.Object

org.datanucleus.store.AbstractPersistenceHandler

org.datanucleus.store.rdbms.RDBMSPersistenceHandler

All Implemented Interfaces:

org.datanucleus.store.StorePersistenceHandler

public class RDBMSPersistenceHandler
extends org.datanucleus.store.AbstractPersistenceHandler

Handler for persistence for RDBMS datastores.

Field Summary

Fields inherited from class org.datanucleus.store.AbstractPersistenceHandler

storeMgr

Constructor Summary

Constructors

Constructor and Description
RDBMSPersistenceHandler(org.datanucleus.store.StoreManager storeMgr) Constructor.

Method Summary

Modifier and Type	Method and Description
void	close() Method to close the handler and release any resources.
void	deleteObject(org.datanucleus.state.ObjectProvider op) Deletes a persistent object from the database.
void	fetchObject(org.datanucleus.state.ObjectProvider op, int[] memberNumbers) Fetches (fields of) a persistent object from the database.
Object	findObject(org.datanucleus.ExecutionContext ec, Object id) Method to return a persistable object with the specified id.
void	insertObject(org.datanucleus.state.ObjectProvider op) Inserts a persistent object into the database.
void	insertObjects(org.datanucleus.state.ObjectProvider... ops)
void	locateObject(org.datanucleus.state.ObjectProvider op) Locates this object in the datastore.
void	locateObjects(org.datanucleus.state.ObjectProvider[] ops)
void	removeAllRequests() Convenience method to remove all requests since the schema has changed.
void	removeRequestsForTable(DatastoreClass table) Convenience method to remove all requests that use a particular table since the structure of the table has changed potentially leading to missing columns in the cached version.
void	updateObject(org.datanucleus.state.ObjectProvider op, int[] fieldNumbers) Updates a persistent object in the database.

Methods inherited from class org.datanucleus.store.AbstractPersistenceHandler

assertReadOnlyForUpdateOfObject, batchEnd, batchStart, deleteObjects, findObjects

Methods inherited from class java.lang.Object

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

Constructor Detail

RDBMSPersistenceHandler

public RDBMSPersistenceHandler(org.datanucleus.store.StoreManager storeMgr)

Constructor.

Parameters:

storeMgr - StoreManager

Method Detail

close

public void close()

Method to close the handler and release any resources.

insertObjects

public void insertObjects(org.datanucleus.state.ObjectProvider... ops)

Specified by:

insertObjects in interface org.datanucleus.store.StorePersistenceHandler

Overrides:

insertObjects in class org.datanucleus.store.AbstractPersistenceHandler

insertObject

public void insertObject(org.datanucleus.state.ObjectProvider op)

Inserts a persistent object into the database. The insert can take place in several steps, one insert per table that it is stored in. e.g When persisting an object that uses "new-table" inheritance for each level of the inheritance tree then will get an INSERT into each table. When persisting an object that uses "complete-table" inheritance then will get a single INSERT into its table.

Parameters:

op - The ObjectProvider of the object to be inserted.

Throws:

org.datanucleus.exceptions.NucleusDataStoreException - when an error occurs in the datastore communication

fetchObject

public void fetchObject(org.datanucleus.state.ObjectProvider op,
                        int[] memberNumbers)

Fetches (fields of) a persistent object from the database. This does a single SELECT on the candidate of the class in question. Will join to inherited tables as appropriate to get values persisted into other tables. Can also join to the tables of related objects (1-1, N-1) as neccessary to retrieve those objects.

Parameters:

op - Object Provider of the object to be fetched.

memberNumbers - The numbers of the members to be fetched.

Throws:

org.datanucleus.exceptions.NucleusObjectNotFoundException - if the object doesn't exist

org.datanucleus.exceptions.NucleusDataStoreException - when an error occurs in the datastore communication

updateObject

public void updateObject(org.datanucleus.state.ObjectProvider op,
                         int[] fieldNumbers)

Updates a persistent object in the database. The update can take place in several steps, one update per table that it is stored in (depending on which fields are updated). e.g When updating an object that uses "new-table" inheritance for each level of the inheritance tree then will get an UPDATE into each table. When updating an object that uses "complete-table" inheritance then will get a single UPDATE into its table.

Parameters:

op - The ObjectProvider of the object to be updated.

fieldNumbers - The numbers of the fields to be updated.

Throws:

org.datanucleus.exceptions.NucleusDataStoreException - when an error occurs in the datastore communication

deleteObject

public void deleteObject(org.datanucleus.state.ObjectProvider op)

Deletes a persistent object from the database. The delete can take place in several steps, one delete per table that it is stored in. e.g When deleting an object that uses "new-table" inheritance for each level of the inheritance tree then will get an DELETE for each table. When deleting an object that uses "complete-table" inheritance then will get a single DELETE for its table.

Parameters:

op - The ObjectProvider of the object to be deleted.

Throws:

org.datanucleus.exceptions.NucleusDataStoreException - when an error occurs in the datastore communication

locateObjects

public void locateObjects(org.datanucleus.state.ObjectProvider[] ops)

Specified by:

locateObjects in interface org.datanucleus.store.StorePersistenceHandler

Overrides:

locateObjects in class org.datanucleus.store.AbstractPersistenceHandler

locateObject

public void locateObject(org.datanucleus.state.ObjectProvider op)

Locates this object in the datastore.

Parameters:

op - ObjectProvider for the object to be found

Throws:

org.datanucleus.exceptions.NucleusObjectNotFoundException - if the object doesnt exist

org.datanucleus.exceptions.NucleusDataStoreException - when an error occurs in the datastore communication

findObject

public Object findObject(org.datanucleus.ExecutionContext ec,
                         Object id)

Method to return a persistable object with the specified id. Optional operation for StoreManagers. Should return a (at least) hollow persistable object if the store manager supports the operation. If the StoreManager is managing the in-memory object instantiation (as part of co-managing the object lifecycle in general), then the StoreManager has to create the object during this call (if it is not already created). Most relational databases leave the in-memory object instantion to Core, but some object databases may manage the in-memory object instantion, effectively preventing Core of doing this.

StoreManager implementations may simply return null, indicating that they leave the object instantiate to us. Other implementations may instantiate the object in question (whether the implementation may trust that the object is not already instantiated has still to be determined). If an implementation believes that an object with the given ID should exist, but in fact does not exist, then the implementation should throw a RuntimeException. It should not silently return null in this case.

Parameters:

ec - execution context

id - the id of the object in question.

Returns:

a persistable object with a valid object state (for example: hollow) or null, indicating that the implementation leaves the instantiation work to us.

removeAllRequests

public void removeAllRequests()

Convenience method to remove all requests since the schema has changed.

removeRequestsForTable

public void removeRequestsForTable(DatastoreClass table)

Convenience method to remove all requests that use a particular table since the structure of the table has changed potentially leading to missing columns in the cached version.

Parameters:

table - The table