er.extensions
Class ERXDatabaseContextDelegate

java.lang.Object
  er.extensions.ERXDatabaseContextDelegate

public class ERXDatabaseContextDelegate

extends Object

This delegate implements several methods from the formal interface EODatabaseContext.Delegate. Of special note this class adds the ability for enterpriseobjects to generate their own primary keys, correctly throws an exception when a toOne relationship object is not found in the database and adds debugging abilities to tracking down when faults are fired.

Field Summary

static ERXLogger	dbLog Faulting logging support, logging category: er.transaction.adaptor.FaultFiring
static ERXLogger	exLog Faulting logging support, logging category: er.transaction.adaptor.Exceptions
static ERXLogger	log Basic logging support

Constructor Summary

ERXDatabaseContextDelegate()

Method Summary

void	_configureReadOnly(Connection aConnection)
void	_configureReadWrite(Connection aConnection)
Connection	_getConnection(EODatabaseContext dbc)
String	_readOnlySessionProperties()
String	_readWriteSessionProperties()
void	databaseContextDidSelectObjects(EODatabaseContext dc, EOFetchSpecification fs, EODatabaseChannel channel) This delegate method is called every time a fault is fired that needs to go to the database.
boolean	databaseContextFailedToFetchObject(EODatabaseContext context, Object object, EOGlobalID gid) This is Kelly Hawks' fix for the missing to one relationship.
NSDictionary	databaseContextNewPrimaryKey(EODatabaseContext databaseContext, Object object, EOEntity entity) Provides the ability for new enterprise objects that implement the interface ERXGeneratesPrimaryKeyInterface to provide their own primary key dictionary.
boolean	databaseContextShouldFetchArrayFault(EODatabaseContext eodatabasecontext, Object obj) Delegate method.
boolean	databaseContextShouldFetchObjectFault(EODatabaseContext dbCtxt, Object obj) Delegate method.
NSArray	databaseContextShouldFetchObjects(EODatabaseContext dbc, EOFetchSpecification fs, EOEditingContext ec) Delegate method.
boolean	databaseContextShouldHandleDatabaseException(EODatabaseContext dbc, Exception e) Allows custom handling of dropped connection exceptions.
boolean	databaseContextShouldHandleDatabaseException(EODatabaseContext databaseContext, Throwable throwable) Provides for a hook to get at the original exceptions from the JDBC driver, as opposed to the cooked EOGeneralAdaptorException you get from EOF.
NSArray	databaseContextWillPerformAdaptorOperations(EODatabaseContext dbCtxt, NSArray adaptorOps, EOAdaptorChannel adChannel) Delegate method.
static ERXDatabaseContextDelegate	defaultDelegate() Returns the singleton of the database context delegate
void	setReadWriteForConnectionInDatabaseContext(boolean isReadWrite, EODatabaseContext dbc) Switch the connection to read/write mode.

Methods inherited from class java.lang.Object

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

Field Detail

log

public static final ERXLogger log

Basic logging support

dbLog

public static final ERXLogger dbLog

Faulting logging support, logging category: er.transaction.adaptor.FaultFiring

exLog

public static final ERXLogger exLog

Faulting logging support, logging category: er.transaction.adaptor.Exceptions

Constructor Detail

ERXDatabaseContextDelegate

public ERXDatabaseContextDelegate()

Method Detail

defaultDelegate

public static ERXDatabaseContextDelegate defaultDelegate()

Returns the singleton of the database context delegate

databaseContextShouldHandleDatabaseException

public boolean databaseContextShouldHandleDatabaseException(EODatabaseContext databaseContext,
                                                            Throwable throwable)

Provides for a hook to get at the original exceptions from the JDBC driver, as opposed to the cooked EOGeneralAdaptorException you get from EOF. To see the exceptions, set the logger er.transaction.adaptor.Exceptions to debug.

Parameters:

databaseContext -

throwable -

Returns:

databaseContextNewPrimaryKey

public NSDictionary databaseContextNewPrimaryKey(EODatabaseContext databaseContext,
                                                 Object object,
                                                 EOEntity entity)

Provides the ability for new enterprise objects that implement the interface ERXGeneratesPrimaryKeyInterface to provide their own primary key dictionary. If the enterprise object implements the above interface then the method primaryKeyDictionary(true) will be called on the object. If the object returns null then a primary key will be generated for the object in the usual fashion.

Parameters:

databaseContext - databasecontext

object - the new enterprise object

entity - the entity of the object

Returns:

primary key dictionary to be used or null if a primary key should be generated for the object.

databaseContextShouldHandleDatabaseException

public boolean databaseContextShouldHandleDatabaseException(EODatabaseContext dbc,
                                                            Exception e)
                                                     throws Throwable

Allows custom handling of dropped connection exceptions. This was needed in WebObjects 4.5 because the OracleEOAdaptor wouldn't correctly handle all exceptions of dropped connections. This may not be needed now.

Parameters:

dbc - current database context

e - throw exception

Returns:

if the exception is one of the bad ones that isn't handled then the method handleDroppedConnection is called directly on the database object of the context and false is returned otherwise true.

Throws:

Throwable

databaseContextFailedToFetchObject

public boolean databaseContextFailedToFetchObject(EODatabaseContext context,
                                                  Object object,
                                                  EOGlobalID gid)

This is Kelly Hawks' fix for the missing to one relationship. Delegate on EODatabaseContext that gets called when a to-one fault cannot find its data in the database. The object that is returned is a cleared fault. We raise here to restore the functionality that existed prior to WebObjects 4.5. Whenever a fault fails for a globalID (i.e. the object is NOT found in the database), we raise an EOObjectNotAvailableException.

Parameters:

context - database context

object - object that is firing the fault for a given to-one relationship

gid - global id that wasn't found in the database.

databaseContextDidSelectObjects

public void databaseContextDidSelectObjects(EODatabaseContext dc,
                                            EOFetchSpecification fs,
                                            EODatabaseChannel channel)

This delegate method is called every time a fault is fired that needs to go to the database. All we have added is logging statement of the debug priority. This way during runtime a developer can toggle the logger priority settting on and off to see what faults are firing. Also note that when using ERXPatternLayout one can set the option to see full backtraces to the calling method. With this option specified a developer can see exactly which methods are firing faults.

Parameters:

dc - the databasecontext

fs - the fetchspecification

channel - the databasechannel

databaseContextWillPerformAdaptorOperations

public NSArray databaseContextWillPerformAdaptorOperations(EODatabaseContext dbCtxt,
                                                           NSArray adaptorOps,
                                                           EOAdaptorChannel adChannel)

Delegate method. Will switch the connection to read write.

databaseContextShouldFetchObjectFault

public boolean databaseContextShouldFetchObjectFault(EODatabaseContext dbCtxt,
                                                     Object obj)

Delegate method. Will switch the connection to read only.

databaseContextShouldFetchArrayFault

public boolean databaseContextShouldFetchArrayFault(EODatabaseContext eodatabasecontext,
                                                    Object obj)

Delegate method. Will switch the connection to read only.

databaseContextShouldFetchObjects

public NSArray databaseContextShouldFetchObjects(EODatabaseContext dbc,
                                                 EOFetchSpecification fs,
                                                 EOEditingContext ec)

Delegate method. Will switch the connection to read only.

setReadWriteForConnectionInDatabaseContext

public void setReadWriteForConnectionInDatabaseContext(boolean isReadWrite,
                                                       EODatabaseContext dbc)

Switch the connection to read/write mode.

Parameters:

isReadWrite - true if the connection should be set to read/write, false if it should be set to read only

dbc - the EODatabaseContext to use to get the java.sql.Connection object FIXME: should support per-model sql statements in order to support different databases

_getConnection

public Connection _getConnection(EODatabaseContext dbc)

_configureReadWrite

public void _configureReadWrite(Connection aConnection)
                         throws SQLException

Throws:

SQLException

_configureReadOnly

public void _configureReadOnly(Connection aConnection)
                        throws SQLException

Throws:

SQLException

_readOnlySessionProperties

public String _readOnlySessionProperties()

_readWriteSessionProperties

public String _readWriteSessionProperties()