/*
 * Copyright 2002-2006 the original author or authors.
 *
 * 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 cyrille.util.concurrent.demo;

import java.io.IOException;
import java.util.concurrent.Semaphore;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * @author <a href="mailto:cyrille.leclerc@pobox.com">Cyrille Le Clerc</a>
 */
@SuppressWarnings("serial")
public class SemaphoreDemoServlet extends HttpServlet {

    // One permit per core on the server
    final Semaphore semaphore = new Semaphore(2);

    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        semaphore.acquireUninterruptibly();
        try {
            // do CPU intensive job
        } finally {
            semaphore.release();
        }
    }
}