SingletonInstance Enhancements / Minor Lock/LockExt API Change (isLocked moved up)

We learned that FileChannel.lock() is not reliable on at least GNU/Linux + Sun's JVM implementation,
hence we need a ServerSocket implementation.

Since this code may be useful to others, it has been promoted to GlueGen.

- Abstract SingletonInstance
- Implement Lock interface
- SingletonInstance Spezialisation: FileLock and ServerSocket

Minor API Change: LockExt.isLocked() -> Lock.isLocked()

1 files changed, 129 insertions, 0 deletions

diff --git a/src/java/jogamp/common/util/locks/SingletonInstanceFileLock.java b/src/java/jogamp/common/util/locks/SingletonInstanceFileLock.java
new file mode 100644
index 0000000..f0bed66
--- /dev/null
+++ b/src/java/jogamp/common/util/locks/SingletonInstanceFileLock.java
@@ -0,0 +1,129 @@
+/**
+ * Copyright 2010 JogAmp Community. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification, are
+ * permitted provided that the following conditions are met:
+ * 
+ *    1. Redistributions of source code must retain the above copyright notice, this list of
+ *       conditions and the following disclaimer.
+ * 
+ *    2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *       of conditions and the following disclaimer in the documentation and/or other materials
+ *       provided with the distribution.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY JogAmp Community ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JogAmp Community OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * 
+ * The views and conclusions contained in the software and documentation are those of the
+ * authors and should not be interpreted as representing official policies, either expressed
+ * or implied, of JogAmp Community.
+ */
+ 
+package jogamp.common.util.locks;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.RandomAccessFile;
+import java.nio.channels.FileLock;
+import com.jogamp.common.util.locks.SingletonInstance;
+
+public class SingletonInstanceFileLock extends SingletonInstance {
+
+    static final String temp_file_path;
+
+    static {
+        String s = null;
+        try {
+            File tmpFile = File.createTempFile("TEST", "tst");
+            String absTmpFile = tmpFile.getCanonicalPath();
+            tmpFile.delete();
+            s = absTmpFile.substring(0, absTmpFile.lastIndexOf(File.separator));
+        } catch (IOException ex) {
+            ex.printStackTrace();
+        }
+        temp_file_path = s;
+    }
+
+    public static String getCanonicalTempPath() {
+        return temp_file_path;
+    }
+
+    public static String getCanonicalTempLockFilePath(String basename) {
+        return getCanonicalTempPath() + File.separator + basename;
+    }
+
+    public SingletonInstanceFileLock(long poll_ms, String lockFileBasename) {
+        super(poll_ms);
+        file = new File ( getCanonicalTempLockFilePath ( lockFileBasename ) );
+        setupFileCleanup();
+    }
+
+    public SingletonInstanceFileLock(long poll_ms, File lockFile) {
+        super(poll_ms);
+        file = lockFile ;
+        setupFileCleanup();
+    }
+
+    public final String getName() { return file.getPath(); }
+    
+    private void setupFileCleanup() {
+        file.deleteOnExit();
+        Runtime.getRuntime().addShutdownHook(new Thread() {
+            public void run() {
+                unlock();
+            }
+        });        
+    }
+
+    @Override
+    protected boolean tryLockImpl() {
+        try {
+            randomAccessFile = new RandomAccessFile(file, "rw");
+            fileLock = randomAccessFile.getChannel().tryLock();
+
+            if (fileLock != null) {
+                return true;
+            }
+        } catch (Exception e) {
+            System.err.println("SLOCK "+System.currentTimeMillis()+" EEE "+getName()+" - Unable to create and/or lock file");
+            e.printStackTrace();
+        }
+        return false;
+    }
+
+    @Override
+    protected boolean unlockImpl() {
+        try {
+            if(null != fileLock) {
+                fileLock.release();
+                fileLock = null;
+            }
+            if(null != randomAccessFile) {
+                randomAccessFile.close();
+                randomAccessFile = null;
+            }
+            if(null != file) {
+                file.delete();
+            }
+            return true;
+        } catch (Exception e) {
+            System.err.println("SLOCK "+System.currentTimeMillis()+" EEE "+getName()+" - Unable to remove lock file");
+            e.printStackTrace();
+        } finally {
+            fileLock = null;
+            randomAccessFile = null;
+        }
+        return false;
+    }
+
+    private final File file;
+    private RandomAccessFile randomAccessFile = null;
+    private FileLock fileLock = null;
+}