1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
|
// Copyright (C) 2009 Red Hat, Inc.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
package net.sourceforge.jnlp.services;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.net.BindException;
import java.net.ServerSocket;
import net.sourceforge.jnlp.JNLPFile;
import net.sourceforge.jnlp.runtime.JNLPRuntime;
import net.sourceforge.jnlp.util.FileUtils;
/**
* This class represents a Lock for single instance jnlp applications
*
* The lock is per-session, per user.
*
* @author <a href="mailto:omajid@redhat.com">Omair Majid</a>
*/
class SingleInstanceLock {
JNLPFile jnlpFile;
File lockFile = null;
public static final int INVALID_PORT = Integer.MIN_VALUE;
int port = INVALID_PORT;
/**
* Create an object to manage the instance lock for the specified JNLP file.
*
* @param jnlpFile the jnlpfile to create the lock for
*/
public SingleInstanceLock(JNLPFile jnlpFile) {
this.jnlpFile = jnlpFile;
lockFile = getLockFile();
}
/**
* Create/overwrite the instance lock for the jnlp file.
*
* @param localPort the network port for the lock
* @throws IOException on any io problems
*/
public void createWithPort(int localPort) throws IOException {
BufferedWriter lockFileWriter = new BufferedWriter(new FileWriter(lockFile, false));
lockFileWriter.write(String.valueOf(localPort));
lockFileWriter.newLine();
lockFileWriter.flush();
lockFileWriter.close();
}
/**
* Returns true if the lock if valid. That is, the lock exists, and port it
* points to is listening for incoming messages.
*/
public boolean isValid() {
return (exists() && getPort() != INVALID_PORT && !isPortFree(getPort()));
}
/**
* Returns the port in this lock file.
*/
public int getPort() {
if (!exists()) {
return INVALID_PORT;
}
try {
parseFile();
} catch (NumberFormatException e) {
port = INVALID_PORT;
} catch (IOException e) {
port = INVALID_PORT;
}
return port;
}
/**
* Returns true if the lock file already exists.
*/
private boolean exists() {
return lockFile.exists();
}
/**
* Returns true if the port is free.
*/
private boolean isPortFree(int port) {
try {
ServerSocket socket = new ServerSocket(port);
socket.close();
return true;
} catch (BindException e) {
return false;
} catch (IOException e) {
throw new RuntimeException(e);
}
}
/**
* Return a file object that represents the lock file. The lock file itself
* may or may not exist.
*/
private File getLockFile() {
File baseDir = new File(JNLPRuntime.LOCKS_DIR);
if (!baseDir.isDirectory() && !baseDir.mkdirs()) {
throw new RuntimeException(R("RNoLockDir", baseDir));
}
String lockFileName = getLockFileName();
File applicationLockFile = new File(baseDir, lockFileName);
return applicationLockFile;
}
/**
* Returns the name of the lock file.
*/
private String getLockFileName() {
String initialName = "";
if (jnlpFile.getSourceLocation() != null) {
initialName = initialName + jnlpFile.getSourceLocation();
} else {
initialName = initialName + jnlpFile.getFileLocation();
}
if (jnlpFile.getFileVersion() != null) {
initialName = initialName + jnlpFile.getFileVersion().toString();
}
initialName = initialName + getCurrentDisplay();
return FileUtils.sanitizeFileName(initialName);
}
/**
* Parse the lock file.
*
* @throws NumberFormatException
* @throws IOException
*/
private void parseFile() throws NumberFormatException, IOException {
BufferedReader lockFileReader = new BufferedReader(new FileReader(lockFile));
int port = Integer.valueOf(lockFileReader.readLine());
lockFileReader.close();
this.port = port;
}
/**
* Returns a string identifying this display.
*
* Implementation note: On systems with X support, this is the DISPLAY
* variable
*
* @return a string that is guaranteed to be not null.
*/
private String getCurrentDisplay() {
String display = System.getenv("DISPLAY");
return (display == null) ? "" : display;
}
private static String R(String key) {
return JNLPRuntime.getMessage(key);
}
private static String R(String key, Object param) {
return JNLPRuntime.getMessage(key, new Object[] { param });
}
}
|
