Java HTTP Port Find getAvailablePort(String hostname, String portRange)

Description

get Available Port

License

Open Source License

Declaration

public static int getAvailablePort(String hostname, String portRange) throws IOException 

Method Source Code

//package com.java2s;
/*/*from   ww w.j a v  a 2  s. c o  m*/
 * Copyright 2005 Sun Microsystems, Inc.
 * Copyright 2005 GigaSpaces, Inc.
 *
 * 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.ServerSocket;

import java.util.StringTokenizer;

public class Main {
    public static int getAvailablePort(String hostname, String portRange) throws IOException {
        StringTokenizer st = new StringTokenizer(portRange, ",");
        while (st.hasMoreTokens()) {
            int index = portRange.indexOf('-');
            if (index == -1) {
                int port = Integer.parseInt(st.nextToken().trim());
                if (port == 0) {
                    return 0;
                }
                try {
                    return getPort(port);
                } catch (IOException e) {
                    // can't create one
                }
            } else {
                int startPort = Integer.parseInt(portRange.substring(0, index));
                int endPort = Integer.parseInt(portRange.substring(index + 1));
                if (endPort < startPort) {
                    throw new IllegalArgumentException(
                            "Start port [" + startPort + "] must be greater than end port [" + endPort + "]");
                }
                for (int i = startPort; i <= endPort; i++) {
                    try {
                        return getPort(i);
                    } catch (IOException ex) {
                        // can't create ont
                    }
                }
            }
        }
        throw new IOException("Failed to get free port from [" + portRange + "]");
    }

    /**
     * This method checks whether supplied port is free.
     *
     * If port 0 returns an anonymous port.
     */
    private static int getPort(int port) throws IOException {
        ServerSocket socket = null;

        try {
            socket = new ServerSocket(port);
            return socket.getLocalPort();
        } finally {
            if (socket != null) {
                try {
                    socket.close();
                } catch (IOException ex) {
                    /* don't care */ }
            }
        }
    }
}

Related

1. getAvailablePort(int port)
2. getAvailablePort(int port)
3. getAvailablePort(int prefferedPort)
4. getAvailablePort(int randomAttempts)
5. getAvailablePort(int startPort)
6. getAvailablePorts(int basePort, int portCount)
7. getAvailablePortsFromRange(int portMin, int portMax, int numberOfPorts)
8. getAvialablePort(final int basePort)
9. getCorrectHostnamePort(String hostPort)