1 // ******************************************************************************
2 //
3 // Title: Force Field X.
4 // Description: Force Field X - Software for Molecular Biophysics.
5 // Copyright: Copyright (c) Michael J. Schnieders 2001-2025.
6 //
7 // This file is part of Force Field X.
8 //
9 // Force Field X is free software; you can redistribute it and/or modify it
10 // under the terms of the GNU General Public License version 3 as published by
11 // the Free Software Foundation.
12 //
13 // Force Field X is distributed in the hope that it will be useful, but WITHOUT
14 // ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
15 // FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
16 // details.
17 //
18 // You should have received a copy of the GNU General Public License along with
19 // Force Field X; if not, write to the Free Software Foundation, Inc., 59 Temple
20 // Place, Suite 330, Boston, MA 02111-1307 USA
21 //
22 // Linking this library statically or dynamically with other modules is making a
23 // combined work based on this library. Thus, the terms and conditions of the
24 // GNU General Public License cover the whole combination.
25 //
26 // As a special exception, the copyright holders of this library give you
27 // permission to link this library with independent modules to produce an
28 // executable, regardless of the license terms of these independent modules, and
29 // to copy and distribute the resulting executable under terms of your choice,
30 // provided that you also meet, for each linked independent module, the terms
31 // and conditions of the license of that module. An independent module is a
32 // module which is not derived from or based on this library. If you modify this
33 // library, you may extend this exception to your version of the library, but
34 // you are not obligated to do so. If you do not wish to do so, delete this
35 // exception statement from your version.
36 //
37 // ******************************************************************************
38 package ffx.utilities;
39
40 import static java.net.InetAddress.getByName;
41
42 import java.net.InetSocketAddress;
43 import java.net.ServerSocket;
44
45 /**
46 * Port Utilities.
47 *
48 * @author Michael J. Schnieders
49 * @since 1.0
50 */
51 public class PortUtils {
52
53 /** The maximum TCP Port. <code>MAX_TCP_PORT=65535</code> */
54 public static final int MAX_TCP_PORT = 65535;
55 /** The minimum TCP Port. <code>MIN_TCP_PORT = 0</code> */
56 private static final int MIN_TCP_PORT = 0;
57
58 /**
59 * Private constructor to prevent instantiation.
60 */
61 private PortUtils() {
62 // Empty constructor.
63 }
64
65 /**
66 * Check if a port is available.
67 *
68 * @param port The port id.
69 * @return True if the port is available.
70 */
71 public static boolean isTcpPortAvailable(int port) {
72 try (ServerSocket serverSocket = new ServerSocket()) {
73 // setReuseAddress(false) is required on OSX.
74 serverSocket.setReuseAddress(false);
75
76 // Try to bind the port.
77 serverSocket.bind(new InetSocketAddress(getByName("localhost"), port), 1);
78 return true;
79 } catch (Exception ex) {
80 return false;
81 }
82 }
83
84 /**
85 * Check if an int matches a valid TCP port (i.e. is a 16-bit unsigned integer).
86 *
87 * @param port A number to check.
88 * @return If port ≥ 0 and ≤ 65535
89 */
90 public static boolean tcpPortValid(int port) {
91 return port >= MIN_TCP_PORT && port <= MAX_TCP_PORT;
92 }
93 }