org.castor.cpa.persistence.sql.keygen

Class MaxKeyGeneratorFactory

java.lang.Object

org.castor.cpa.persistence.sql.keygen.MaxKeyGeneratorFactory

All Implemented Interfaces:

KeyGeneratorFactory

public final class MaxKeyGeneratorFactory
extends Object
implements KeyGeneratorFactory

MAX key generator factory. The short name of this key generator is "MAX".
It uses the following alrorithm: the maximum value of the primary key is fetched and the correspondent record is locked until the end of transaction, generator returns (max + 1). The lock guarantees that key generators of concurrent transactions will not use this key value, so DuplicateKeyException is impossible. If the table is empty, generator returns 1, no lock is put, DuplicateKeyException is possible.

Version:

$Revision: 8093 $ $Date: 2006-04-25 15:08:23 -0600 (Tue, 25 Apr 2006) $

Author:

Oleg Nitz, Ralf Joachim

See Also:

MaxKeyGenerator

Constructor Summary

Constructors

Constructor and Description
MaxKeyGeneratorFactory()

Method Summary

Methods

Modifier and Type	Method and Description
KeyGenerator	getKeyGenerator(PersistenceFactory factory, Properties params, int sqlType) Produce the key generator.
String	getKeyGeneratorName() Get the short name of the key generator.

Methods inherited from class java.lang.Object

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

Constructor Detail

MaxKeyGeneratorFactory

public MaxKeyGeneratorFactory()

Method Detail

getKeyGeneratorName

public String getKeyGeneratorName()

Get the short name of the key generator. It is used to reference key generators in a mapping configuration file. If several key generators of the same type are used for the same database, then they are referenced by aliases.

Specified by:

getKeyGeneratorName in interface KeyGeneratorFactory

Returns:

Name of the KeyGenerator used to identify key generator (types).

getKeyGenerator

public KeyGenerator getKeyGenerator(PersistenceFactory factory,
                           Properties params,
                           int sqlType)
                             throws MappingException

Produce the key generator.

Specified by:

getKeyGenerator in interface KeyGeneratorFactory

Parameters:

factory - Helper object for obtaining database-specific QuerySyntax.

params - Parameters for key generator.

sqlType - The SQL type of the primary key, the generated identities must have the corresponding Java type, e.g. java.sql.Types.INTEGER corresponds to java.lang.Integer, java.sql.Types.NUMERIC corresponds to java.lang.BigDecimal.

Returns:

A KeyGenerator instance.

Throws:

MappingException - If there's a problem resolving the mapping information.