C.1 Interfaces
An application uses the following Java interfaces and JDOHelper class in a JDO environment.
| Extent |
An Extent is used to access all of the instances of a particular class and, optionally, its subclasses. An application can either iterate over all the instances or use the extent as the set of candidates instances filtered with a Query.
public interface Extent {
public void close(Iterator it);
public void closeAll( );
public Class getCandidateClass( );
public PersistenceManager getPersistenceManager( );
public boolean hasSubclasses( );
public Iterator iterator( );
}
Returned by
PersistenceManager.getExtent( )
Passed to
PersistenceManager.newQuery( ), Query.setCandidates( )
| InstanceCallbacks |
A persistent class can implement the InstanceCallbacks interface so that the following callback methods are called when particular lifecycle events occur:
public interface InstanceCallbacks {
public void jdoPostLoad( );
public void jdoPreClear( );
public void jdoPreDelete( );
public void jdoPreStore( );
}
| JDOHelper |
This helper class provides applications with several utility methods. It provides methods to perform the following functions:
Construct a PersistenceManagerFactory instance via a Properties object
Interrogate the lifecycle state of an instance
Get the object identifier of an instance
Mark a field of an instance as modified
public class JDOHelper {
public JDOHelper( );
public static Object getObjectId(Object obj);
public static PersistenceManager
getPersistenceManager(Object obj);
public static PersistenceManagerFactory
getPersistenceManagerFactory(Properties props);
public static PersistenceManagerFactory
getPersistenceManagerFactory(Properties props,
ClassLoader cl);
public static Object getTransactionalObjectId(Object obj);
public static boolean isDeleted(Object obj);
public static boolean isDirty(Object obj);
public static boolean isNew(Object obj);
public static boolean isPersistent(Object obj);
public static boolean isTransactional(Object obj);
public static void makeDirty(Object obj, String fieldName);
}
| PersistenceManager |
The PersistenceManager interface is the primary interface for JDO-aware software. It is the factory for Query and Transaction instances, and it contains methods to manage the lifecycle of instances.
public interface PersistenceManager {
public void close( );
public Transaction currentTransaction( );
public void deletePersistent(Object obj);
public void deletePersistentAll(Object[] objs);
public void deletePersistentAll(Collection objs);
public void evict(Object obj);
public void evictAll(Object[] objs);
public void evictAll(Collection objs);
public void evictAll( );
public Extent getExtent(Class persistenceCapableClass,
boolean subclasses);
public boolean getIgnoreCache( );
public boolean getMultithreaded( );
public Object getObjectById(Object oid, boolean validate);
public Object getObjectId(Object obj);
public Class getObjectIdClass(Class cls);
public PersistenceManagerFactory
getPersistenceManagerFactory( );
public Object getTransactionalObjectId(Object obj);
public Object getUserObject( );
public boolean isClosed( );
public void makeNontransactional(Object obj);
public void makeNontransactionalAll(Object[] objs);
public void makeNontransactionalAll(Collection objs);
public void makePersistent(Object obj);
public void makePersistentAll(Object[] objs);
public void makePersistentAll(Collection objs);
public void makeTransactional(Object obj);
public void makeTransactionalAll(Object[] objs);
public void makeTransactionalAll(Collection objs);
public void makeTransient(Object obj);
public void makeTransientAll(Object[] objs);
public void makeTransientAll(Collection objs);
public Object newObjectIdInstance(Class pcClass, String str);
public Query newQuery( );
public Query newQuery(Object compiled);
public Query newQuery(String language, Object query);
public Query newQuery(Class cls);
public Query newQuery(Extent cln);
public Query newQuery(Class cls, Collection cln);
public Query newQuery(Class cls, String filter);
public Query newQuery(Class cls, Collection cln, String filter);
public Query newQuery(Extent cln, String filter);
public void refresh(Object obj);
public void refreshAll(Object[] objs);
public void refreshAll(Collection objs);
public void refreshAll( );
public void retrieve(Object obj);
public void retrieveAll(Collection objs);
public void retrieveAll(Collection objs, boolean DFGonly);
public void retrieveAll(Object[] objs);
public void retrieveAll(Object[] objs, boolean DFGonly);
public void setIgnoreCache(boolean flag);
public void setMultithreaded(boolean flag);
public void setUserObject(Object o);
}
Returned by:
PersistenceManagerFactory.getPersistenceManager( ),Extent.getPersistenceManager( ), Query.getPersistenceManager( ),Transaction.getPersistenceManager( ),JDOHelper.getPersistenceManager( )
| PersistenceManagerFactory |
The PersistenceManagerFactory is used to obtain PersistenceManager instances. All PersistenceManager instances obtained from the same PersistenceManagerFactory will have the same default properties.
PersistenceManagerFactory instances may be configured and serialized for later use. They may be stored via JNDI and looked up and used later. Any configured properties will be saved and restored.
If the ConnectionFactory property is set (non-null) then all the other connection properties (including ConnectionFactoryName) are ignored; otherwise, if ConnectionFactoryName is set (non-null) then all other connection properties are ignored. Similarly, if the ConnectionFactory2 property is set (non-null), then ConnectionFactory2Name is ignored.
public interface PersistenceManagerFactory implements Serializable {
public void close( );
public String getConnectionDriverName( );
public Object getConnectionFactory( );
public Object getConnectionFactory2( );
public String getConnectionFactory2Name( );
public String getConnectionFactoryName( );
public String getConnectionURL( );
public String getConnectionUserName( );
public boolean getIgnoreCache( );
public boolean getMultithreaded( );
public boolean getNontransactionalRead( );
public boolean getNontransactionalWrite( );
public boolean getOptimistic( );
public PersistenceManager getPersistenceManager( );
public PersistenceManager getPersistenceManager(String userid, String password);
public Properties getProperties( );
public boolean getRestoreValues( );
public boolean getRetainValues( );
public void setConnectionDriverName(String driverName);
public void setConnectionFactory(Object connectionFactory);
public void setConnectionFactory2(Object connectionFactory);
public void setConnectionFactory2Name(
String connectionFactoryName);
public void setConnectionFactoryName(
String connectionFactoryName);
public void setConnectionPassword(String password);
public void setConnectionURL(String URL);
public void setConnectionUserName(String userName);
public void setIgnoreCache(boolean flag);
public void setMultithreaded(boolean flag);
public void setNontransactionalRead(boolean flag);
public void setNontransactionalWrite(boolean flag);
public void setOptimistic(boolean flag);
public void setRestoreValues(boolean restoreValues);
public void setRetainValues(boolean flag);
public Collection supportedOptions( );
}
Returned by
JDOHelper.getPersistenceManagerFactory( ),PersistenceManager.getPersistenceManagerFactory( )
| Query |
The Query interface allows applications to obtain persistent instances from the datastore. The PersistenceManager is the factory for Query instances. There may be many Query instances associated with a PersistenceManager.
public interface Query implements Serializable {
public void closeAll( );
public void compile( );
public void declareImports(String imports);
public void declareParameters(String parameters);
public void declareVariables(String variables);
public Object execute( );
public Object execute(Object p1);
public Object execute(Object p1, Object p2);
public Object execute(Object p1, Object p2, Object p3);
public Object executeWithArray(Object[] parameters);
public Object executeWithMap(Map parameters);
public boolean getIgnoreCache( );
public PersistenceManager getPersistenceManager( );
public void setCandidates(Extent objs);
public void setCandidates(Collection objs);
public void setClass(Class cls);
public void setFilter(String filter);
public void setIgnoreCache(boolean ignoreCache);
public void setOrdering(String ordering);
}
Returned by
PersistenceManager.newQuery( )
| Transaction |
The Transaction interface provides for initiation and completion of transactions under user control. It also provides methods for setting various options that control transaction behavior during a transaction and cache behavior after the transaction completes.
public interface Transaction {
public void begin( );
public void commit( );
public boolean getNontransactionalRead( );
public boolean getNontransactionalWrite( );
public boolean getOptimistic( );
public PersistenceManager getPersistenceManager( );
public boolean getRestoreValues( );
public boolean getRetainValues( );
public Synchronization getSynchronization( );
public boolean isActive( );
public void rollback( );
public void setNontransactionalRead(
boolean nontransactionalRead);
public void setNontransactionalWrite(
boolean nontransactionalWrite);
public void setOptimistic(boolean optimistic);
public void setRestoreValues(boolean restoreValues);
public void setRetainValues(boolean retainValues);
public void setSynchronization(Synchronization sync);
}
Returned by
PersistenceManager.currentTransaction( )
