ProviderFactory.java

/*
 * HA-JDBC: High-Availability JDBC
 * Copyright (C) 2014  Paul Ferraro
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package net.sf.hajdbc;

import java.util.ServiceLoader;

import net.sf.hajdbc.messages.simple.SimpleMessages;

public class ProviderFactory<P extends Provider>
{
	private final P provider;

	protected ProviderFactory(Class<P> providerClass)
	{
		this.provider = findProvider(providerClass);
	}

	private static <P extends Provider> P findProvider(Class<P> providerClass)
	{
		for (P provider: ServiceLoader.load(providerClass, providerClass.getClassLoader()))
		{
			if (provider.isEnabled())
			{
				return provider;
			}
		}
		throw new IllegalStateException(new SimpleMessages().serviceNotFound(providerClass));
	}

	protected P getProvider()
	{
		return this.provider;
	}
}