X-Git-Url: http://source.jalview.org/gitweb/?a=blobdiff_plain;ds=inline;f=src%2Forg%2Fvamsas%2Fclient%2Fsimpleclient%2FLock.java;h=dfc978ee85f6701db952bc33d8ffad67c30418c4;hb=22f2540fb101614e50bbbd7369e968f665d64b3b;hp=d7239e61ebf4af80352f687167926e141093f1a2;hpb=60d3fb8b4c31842b601284e79906e8f8bc63c4f8;p=vamsas.git
diff --git a/src/org/vamsas/client/simpleclient/Lock.java b/src/org/vamsas/client/simpleclient/Lock.java
index d7239e6..dfc978e 100644
--- a/src/org/vamsas/client/simpleclient/Lock.java
+++ b/src/org/vamsas/client/simpleclient/Lock.java
@@ -8,15 +8,15 @@ import java.nio.channels.FileLock;
/**
* transient object representing a file lock
- *
- *
+ * This lock should hold for all processes interacting in a session.
+ * TODO: currently implemented for local filesystem style locking - need a fallback mechanism for systems without file locks.
* @author jimp
*
*/
public class Lock {
FileLock lock = null;
- RandomAccessFile rafile;
+ RandomAccessFile rafile=null;
/**
* creates a valid Lock (test with isLocked)
* if a lock could be obtained for lockfile
@@ -25,14 +25,17 @@ public class Lock {
public Lock(java.io.File lockfile) {
// try and get a lock.
lock = null;
-
+
try {
if (!lockfile.exists())
if (!lockfile.createNewFile()) {
return;
}
-
+
lock = (rafile=new RandomAccessFile(lockfile,"rw")).getChannel().tryLock();
+ if (lock==null || !lock.isValid())
+ // failed to get lock. Close the file channel
+ rafile.getChannel().close();
} catch (FileNotFoundException e) {
System.err.println("Error! Couldn't create a lockfile at "
+ lockfile.getAbsolutePath());
@@ -43,20 +46,33 @@ public class Lock {
e.printStackTrace();
}
}
-
+
boolean isLocked() {
if (lock != null && lock.isValid()) {
return true;
}
return false;
}
-
+ public void release() {
+ try {
+ // TODO: verify that channel.close should be called after release() for rigourous locking.
+ if (lock!=null && lock.isValid())
+ lock.release();
+ if (rafile!=null && rafile.getChannel().isOpen())
+ rafile.getChannel().close();
+ } catch (IOException e) {
+ // TODO Auto-generated catch block
+ e.printStackTrace(System.err);
+ }
+ lock=null;
+ rafile=null;
+ }
+
/* Explicitly release lock (probably don't need to do this!)
* @see java.lang.Object#finalize()
*/
protected void finalize() throws Throwable {
- if (lock!=null)
- lock.release();
+ release();
super.finalize();
}