db ojb

The FieldConversion>/code> interface defines two callback methods for conversion from Java to Database (javaToSql(Object source)) and from Database to Java (sqlToJava(Object source)).
OJB users can use predefined FieldConversion implementations contained in this package and can also implement their own conversions that perform arbitrary mappings. The usage of a FieldConversion must be declared in the FieldDescriptor element in the repository.xml file.

The conversion-methods of the FieldConversion>/code> interface may throw a ConversionException to signal errors during the conversion operations.

The class FieldConversionDefaultImpl is the default implementation of the FieldConversion>/code> interface. This implementation does not modify its input.

The class Boolean2IntFieldConversion is an implementation of the FieldConversion>/code> interface that provides a conversion from persistent classes attributes of type Boolean to rdbms columns of type BIGINT, INTEGER, SMALLINT, TINYINT or BIT.

The class JavaDate2SqlDateFieldConversion is an implementation of the FieldConversion>/code> interface that provides a conversion from persistent classes attributes of type java.util.Date to rdbms columns of type java.sql.Date.

The class Object2ByteArrFieldConversion is an implementation of the FieldConversion>/code> interface that provides a conversion from persistent classes attributes of type java.lang.Object (or any subtype) to rdbms columns of a type able of holding byte arrays (CHAR, VARCHAR, LONGVARCHAR, BINARY, VARBINARY, or LONGVARBINARY).
This conversion can be useful if embedded objects can not be mapped on a dedicated extra table but must be "inlined". This approach is used for the mapping of DListEntry object that hold an inlined Identity Object.

Patterns applied: Callback, Strategy

Todo: Provide more predefined implementations

This package contains the OJB SQL generator classes.

This package provides classes for caching of objects materialized from a datastore.

Applications use the ObjectCacheFactory to create new ObjectCaches. These caches supply methods for storing and retrieving objects. Objects can be looked up by their identity which is represented by the class Identiy. Each implementation of ObjectCache represents a different caching strategy.

This package provides classes for accessing fields of persistent classes.

The Platform interface provides callbacks that allow to perform RDBMS Platform specific operations whereever neccessary.

The class PlatformDefaultImpl implements Platform and provides default implementations of all methods.

For each supported Platform Xxx there is a class PlatformXxxImpl which extends PlatformDefaultImpl and may override the methods of the baseclass.

The factory class PlatformFactory can be used to create Platform instances. It uses information from a JdbcConnectionDescriptor to select the appropriate PlatformXxxImpl class.

Patterns applied: Configurable Factory, Strategy, Bridge

Todo: Provide more Platform-Implementations

The class ManageableVector extends Vector and implements ManageableCollections.

The class ManageableArrayList extends ArrayList and implements ManageableCollections.

The class ManageableHashSet extends HashSet and implements ManageableCollections.

Patterns applied: Adapter, Callback interface ("don't call us, we call you")

Todo: Provide more such implementations.

The Configuration interface defines lookup-methods to lookup typed configuration-values. For example boolean getBoolean(String key, boolean defaultValue) looks up a boolean value associated with key.

The Configurable interface defines a callback method configure(Configuration pConfig). Implementors of this method may use configuration value from the pConfig parameter to configure the current instance.

The Configurator interface defines methods for looking up Configurations and for configuring Configurable instances.

The Exception ConfigurationException is used to signal exceptions in the configuration process.

Patterns applied: Callback

Todo: merge with jakarta commons-configuration API

The Logger interface defines the behaviour of the OJB logging mechanism. This API corresponds closely to the LOG4J Category Api. By using this interface for logging operations OJB remains free from Logger-Implementation specific code.

The class PoorMansLoggerImpl implements Logger and provides the OJB default implementations. All logging output is directed to System.out.

The class Log4jLoggerImpl implements Logger and provides LOG4J based logger implementations.

The factory class LoggerFactory can be used to create Logger instances. The Logger-implementation class served by the factory is configured by settings in the OJB.properties file.

Patterns applied: Configurable Factory, Adapter

Todo: Provide a JDK1.4 based logger