bookkeeper-server/src/test/java/org/apache/bookkeeper/test/PortManager.java

/*
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.bookkeeper.test;

import java.net.ServerSocket;
/**
 * Port manager allows a base port to be specified on the commandline.
 * Tests will then use ports, counting up from this base port.
 * This allows multiple instances of the bookkeeper tests to run at once.
 */
public class PortManager {
    private static int nextPort = getBasePort();

    public static synchronized int nextFreePort() {
        int exceptionCount = 0;
        while (true) {
            int port = nextPort++;
            try (ServerSocket ss = new ServerSocket(port)) {
                ss.close();
                //Give it some time to truly close the connection
                Thread.sleep(100);
                return port;
            } catch (Exception e) {
                exceptionCount++;
                if (exceptionCount > 5) {
                    throw new RuntimeException(e);
                }
            }
        }
    }

    private static int getBasePort() {
        return Integer.valueOf(System.getProperty("test.basePort", "15000"));
    }
}