Package org.castor.cpa.persistence.sql.keygen

Class MaxKeyGeneratorFactory

  • All Implemented Interfaces:
    KeyGeneratorFactory
    public final class MaxKeyGeneratorFactory
extends java.lang.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 Detail

      • MaxKeyGeneratorFactory

        public MaxKeyGeneratorFactory()

    • Method Detail

      • getKeyGeneratorName

        public java.lang.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,
                                    java.util.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.