package org.apache.torque.engine.database.model;
/*
* Copyright 2001-2004 The Apache Software Foundation.
*
* 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.
*/
import java.util.Hashtable;
import java.util.List;
import org.apache.torque.engine.EngineException;
/**
* A name generation factory.
*
* @author <a href="mailto:dlr@finemaltcoding.com>Daniel Rall</a>
* @version $Id: NameFactory.java,v 1.5.2.2 2004/05/20 04:34:15 seade Exp $
*/
public class NameFactory
{
/**
* The fully qualified class name of the Java name generator.
*/
public static final String JAVA_GENERATOR =
JavaNameGenerator.class.getName();
/**
* The fully qualified class name of the constraint name generator.
*/
public static final String CONSTRAINT_GENERATOR =
ConstraintNameGenerator.class.getName();
/**
* The single instance of this class.
*/
private static NameFactory instance = new NameFactory();
/**
* The cache of <code>NameGenerator</code> algorithms in use for
* name generation, keyed by fully qualified class name.
*/
private Hashtable algorithms;
/**
* Creates a new instance with storage for algorithm implementations.
*/
protected NameFactory()
{
algorithms = new Hashtable(5);
}
/**
* Factory method which retrieves an instance of the named generator.
*
* @param name The fully qualified class name of the name
* generation algorithm to retrieve.
* @return A name generator
*/
protected NameGenerator getAlgorithm(String name)
throws EngineException
{
synchronized (algorithms)
{
NameGenerator algorithm = (NameGenerator) algorithms.get(name);
if (algorithm == null)
{
try
{
algorithm =
(NameGenerator) Class.forName(name).newInstance();
}
catch (InstantiationException e)
{
throw new EngineException("Unable to instantiate class "
+ name + ": Make sure it's in your run-time classpath", e);
}
catch (Exception e)
{
throw new EngineException(e);
}
algorithms.put(name, algorithm);
}
return algorithm;
}
}
/**
* Given a list of <code>String</code> objects, implements an
* algorithm which produces a name.
*
* @param algorithmName The fully qualified class name of the
* {@link org.apache.torque.engine.database.model.NameGenerator}
* implementation to use to generate names.
* @param inputs Inputs used to generate a name.
* @return The generated name.
* @throws EngineException an exception
*/
public static String generateName(String algorithmName, List inputs)
throws EngineException
{
NameGenerator algorithm = instance.getAlgorithm(algorithmName);
return algorithm.generateName(inputs);
}
}