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1
11 package org.eclipse.help.internal.server;
12
13 import java.io.IOException  ;
14 import java.net.InetAddress ;
15 import java.net.InetSocketAddress ;
16 import java.net.ServerSocket ;
17 import java.net.SocketAddress ;
18 import java.net.UnknownHostException ;
19 import java.util.Random ;
20
21
24 public class SocketUtil {
25
26 private static final Random RANDOM = new Random ();
27
28
31 public static int findUnusedLocalPort() {
32 InetAddress address;
33 try {
34 address = InetAddress.getByAddress(new byte[] { 127, 0, 0, 1 });
35 } catch (UnknownHostException uhe) {
36 return -1;
37 }
38
39 int port = findUnusedPort(address, 49152, 65535);
40 if (port == -1) {
41 port = findFreePort();
42 }
43 return port;
44 }
45
46 private static int findUnusedPort(InetAddress address, int from, int to) {
47 for (int i = 0; i < 12; i++) {
48 ServerSocket ss = null;
49 int port = getRandomPort(from, to);
50 try {
51 ss = new ServerSocket ();
52 SocketAddress sa = new InetSocketAddress (address, port);
53 ss.bind(sa);
54 return ss.getLocalPort();
55 } catch (IOException e) {
56 } finally {
57 if (ss != null) {
58 try {
59 ss.close();
60 } catch (IOException ioe) {
61 }
62 }
63 }
64 }
65 return -1;
66 }
67
68 private static int getRandomPort(int low, int high) {
69 return (int)(RANDOM.nextFloat() * (high - low)) + low;
70 }
71
72 private static int findFreePort() {
73 ServerSocket socket = null;
74 try {
75 socket = new ServerSocket (0);
76 return socket.getLocalPort();
77 } catch (IOException e) {
78 } finally {
79 if (socket != null) {
80 try {
81 socket.close();
82 } catch (IOException e) {
83 }
84 }
85 }
86 return -1;
87 }
88 }
89 |
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