/**
 * Copyright (c) 2002-2013 "Neo Technology,"
 * Network Engine for Objects in Lund AB [http://neotechnology.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.neo4j.helpers;

import java.util.concurrent.atomic.AtomicLongFieldUpdater;

public abstract class Counter
{
    public abstract void inc();

    public abstract long count();

    public static Counter atomic()
    {
        return new AtomicCounter();
    }

    private static class AtomicCounter extends Counter
    {
        private volatile long count;
        private static final AtomicLongFieldUpdater<AtomicCounter> COUNT = AtomicLongFieldUpdater.newUpdater(
                AtomicCounter.class, "count" );

        @Override
        public void inc()
        {
            COUNT.incrementAndGet( this );
        }

        @Override
        public long count()
        {
            return count;
        }
    }
}