Java HTTP Port Find searchPort(int number, int even, boolean stream)

Description

Searches for a number of successive free ports in the range between minPort and maxPort

License

Open Source License

Parameter

Parameter	Description
number	Number of Ports requested
even	first Port Number should be even (2) , odd (1) or random (0)
stream	search for TCP (true) or UDP (false) Socket

Exception

Parameter	Description
SocketException	an exception

Return

free port number to be used (if multiple numbers were requested this is the first of number successive numbers

Declaration

public static int searchPort(int number, int even, boolean stream) throws SocketException

Method Source Code

//package com.java2s;

import java.io.IOException;

import java.net.DatagramSocket;

import java.net.ServerSocket;
import java.net.SocketException;

import java.net.UnknownHostException;

import java.util.Vector;

public class Main {
    private static int minPort = 49152;
    private static int maxPort = 65535;
    private static Vector<Integer> assignedPorts = new Vector<Integer>();

    /**/*from www .ja  v a2 s.  c  o m*/
     *
     * Searches for a number of successive free ports in the range between minPort and maxPort
     *
     * @param number Number of Ports requested
     * @param even first Port Number should be even (2) , odd (1) or random (0)
     * @param stream search for TCP (true) or UDP (false) Socket
     * @return free port number to be used (if multiple numbers were requested this
     * is the first of number successive numbers
     * @throws SocketException
     */
    public static int searchPort(int number, int even, boolean stream) throws SocketException {
        boolean found = false;
        int offset = 0;
        int port = minPort;
        while (!found) {
            switch (even) {
            case 2:
                port = minPort + 2 * offset;
                break;
            case 1:
                port = minPort + 2 * offset + 1;
                break;
            default:
                port = minPort + offset;
            }
            for (int i = 0; i < number; i++) {
                if ((port + i) > maxPort) {
                    throw new SocketException("No port in Range found");
                } else if (!assignedPorts.contains(new Integer(port + i))) {
                    System.err.println((port + i) + " is not assigned");
                    try {
                        if (stream) {
                            ServerSocket test = new ServerSocket(port + i);
                            found = true;
                            test.close();
                        } else {
                            DatagramSocket test = new DatagramSocket(port + i);
                            found = true;
                            test.close();
                        }
                    } catch (SocketException e) {
                        found = false;
                        offset++;
                        break;
                    } catch (UnknownHostException e) {
                        // this should not happen
                        e.printStackTrace();
                    } catch (IOException e) {
                        found = false;
                        offset++;
                        break;
                    }
                } else {
                    found = false;
                    offset++;
                    break;
                }
            }
        }
        for (int i = 0; i < number; i++) {
            System.err.println((port + i) + " assigned");
            assignedPorts.add(new Integer(port + i));
        }
        return port;
    }
}