Java HTTP Port Find getValidZooKeeperPort()

Description

Check from DEFAULT_ZK_PORT to (DEFAULT_ZK_PORT + TRY_PORT_COUNT) to see if there is valid port to launch embed zookeeper server.

License

Apache License

Return

valid zookeeper port

Declaration

public static int getValidZooKeeperPort() 

Method Source Code

//package com.java2s;
/*//from w  ww  .  ja  v a  2  s. co m
 * Copyright [2013-2014] eBay 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.io.IOException;

import java.net.InetAddress;
import java.net.Socket;

import java.net.UnknownHostException;

import java.util.Random;

public class Main {
    private static final int DEFAULT_ZK_PORT = 2181;
    /**
     * Client connection retry count
     */
    public static final int RETRY_COUNT = 4;
    /**
     * How many ports will be used to launch embed zookeeper server.
     */
    public static final int TRY_PORT_COUNT = 20;
    /**
     * Initial zookeeper port used for check valid zookeeper port.
     */
    public static final int INITAL_ZK_PORT = -1;
    private static final Random RANDOM = new Random();

    /**
     * Check from DEFAULT_ZK_PORT to (DEFAULT_ZK_PORT + TRY_PORT_COUNT) to see if there is valid port to launch embed
     * zookeeper server.
     * 
     * @return valid zookeeper port
     */
    public static int getValidZooKeeperPort() {
        int zkValidPort = INITAL_ZK_PORT;
        int initialPort = DEFAULT_ZK_PORT;
        // add random port to avoid port in the same small range.
        if (System.currentTimeMillis() % 2 == 0) {
            zkValidPort += RANDOM.nextInt(100);
        } else {
            zkValidPort -= RANDOM.nextInt(100);
        }
        for (int i = initialPort; i < (initialPort + TRY_PORT_COUNT); i++) {
            try {
                if (!isServerAlive(InetAddress.getLocalHost(), i)) {
                    zkValidPort = i;
                    break;
                }
            } catch (UnknownHostException e) {
                throw new RuntimeException(e);
            }
        }
        if (zkValidPort == INITAL_ZK_PORT) {
            throw new RuntimeException(
                    "Too many ports are used, please submit guagua app later or specify one zookeeper instance.");
        }
        return zkValidPort;
    }

    /**
     * Check whether a server is alive.
     * 
     * @param host
     *            the server host
     * @param port
     *            the server port
     * @return true if a server is alive, false if a server is not alive.
     */
    public static boolean isServerAlive(InetAddress host, int port) {
        Socket socket = null;
        int i = 0;
        while (i < RETRY_COUNT) {
            try {
                socket = new Socket(host, port);
                break;
            } catch (IOException e) {
                i++;
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e1) {
                    Thread.currentThread().interrupt();
                }
            } finally {
                try {
                    if (socket != null) {
                        socket.close();
                    }
                } catch (IOException ignore) {
                }
            }
        }

        return i != RETRY_COUNT;
    }

    /**
     * Check whether a server is alive.
     * 
     * @param host
     *            the server host
     * @param port
     *            the server port
     * @return true if a server is alive, false if a server is not alive.
     */
    public static boolean isServerAlive(String host, int port) {
        Socket socket = null;
        int i = 0;
        while (i++ < RETRY_COUNT) {
            try {
                socket = new Socket(host, port);
                break;
            } catch (IOException e) {
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e1) {
                    Thread.currentThread().interrupt();
                }
            } finally {
                try {
                    if (socket != null) {
                        socket.close();
                    }
                } catch (IOException ignore) {
                }
            }
        }

        return i < RETRY_COUNT;
    }
}

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3. getUnusedPort(final int start)
4. getUnusedPort(int startPort)
5. getUnusedPorts(final int count, final int start)
6. getWsdlLocation(String portPrefix)
7. getXmlReport(String fileName)
8. hasPermissionToBindPort(int port)
9. isActivePort(int port)