/*
* Copyright 2008 Oleg Nitz, Ralf Joachim
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.castor.cpa.persistence.sql.keygen;
import java.util.Properties;
import org.exolab.castor.mapping.MappingException;
import org.exolab.castor.persist.spi.PersistenceFactory;
/**
* HIGH-LOW key generator factory. The short name of this key generator is "HIGH-LOW".
* <br/>
* It uses the following alrorithm: a special sequence table must be in the database which keeps
* the maximum key values. The name of the sequence table is a mandatory parameter of the key
* generator, the parameter name is "table". The name of the primary key column of the sequence
* table and the name of the column in which maximum values are stored are mandatory parameters
* with the names "key-column" and "value-column", respectively. The key column contains table
* names, so it must be of a character type (char or varchar). The value column contains primary
* key values, it must be of a numeric type (numeric or int). Key generator reads the maximum
* value X for the given table, writes the new value (X + N) to the sequence table and during
* next N calls returns values X + 1, ..., X + N without database access. Number N called
* "grab size" is an optional parameter of the key generator, its parameter name is "grab-size",
* default value is "10". For example, if you want to obtain HIGH-LOW key generator with 3 digits
* in the LOW part of the key, you should set "grab-size" to "1000".
*
* @see HighLowKeyGenerator
* @author <a href="mailto:on AT ibis DOT odessa DOT ua">Oleg Nitz</a>
* @author <a href="mailto:ralf DOT joachim AT syscon DOT eu">Ralf Joachim</a>
* @version $Revision$ $Date: 2006-04-25 15:08:23 -0600 (Tue, 25 Apr 2006) $
*/
public final class HighLowKeyGeneratorFactory implements KeyGeneratorFactory {
//-----------------------------------------------------------------------------------
/**
* {@inheritDoc}
*/
public String getKeyGeneratorName() { return "HIGH-LOW"; }
/**
* {@inheritDoc}
*/
public KeyGenerator getKeyGenerator(final PersistenceFactory factory,
final Properties params, final int sqlType) throws MappingException {
return new HighLowKeyGenerator(factory, params, sqlType);
}
//-----------------------------------------------------------------------------------
}