import java.util.Vector;
/**
- * @author jim Handler for the clientsFile within a vamsas session.
+ * Handler for the clientsFile within a vamsas session thread.
+ * @author jim
*/
-public class ClientsFile {
- private File filelist;
-
+public class ClientsFile extends ListFile {
/**
- * number of my client in list (not known at start but used when known to make
- * lock)
+ * number of my client in list - passed back when a client
+ * is added to list, and used (if valid) for quickly
+ * looking up presence of client handle in the list.
*/
private int syncnum = 1;
public ClientsFile(File filelist) throws IOException {
- this.filelist = filelist;
- if (!this.filelist.exists())
- this.filelist.createNewFile();
- }
-
- private Lock listlock = null;
-
- /**
- * Get a lock for the ClientsFile
- *
- * @return true if lock was made
- */
- protected boolean lockList() {
- if (listlock != null && listlock.isLocked())
- return true;
- listlock = null;
- if (filelist != null) {
- if (filelist.exists()) {
- // TODO: see if we need to loop-wait for locks or they just block until
- // lock is made...
- do {
- listlock = new Lock(filelist); // TODO: wait around if we can't get the lock.
- } while (!listlock.isLocked());
- // listlock = new Lock(filelist);
- return listlock.isLocked();
- }
- } else
- throw new Error(
- "org.vamsas.client.simpleclient.ClientsFile.lockList called for non-initialised ClientsFile!");
-
- // no lock possible
- return false;
- }
-
- /**
- * Explicitly release the ClientsFile lock.
- *
- * @return true if lock was released.
- */
- protected void unlockList() {
- if (listlock != null) {
-
- if (listlock.isLocked()) {
- listlock.release();
- }
-
- listlock = null;
- }
+ super(filelist);
}
/**
* @return list of clients
*/
private ClientHandle[] retrieveClientHandles() {
- if (lockList()) {
+ if (lockFile()) {
try {
ClientHandle[] clients=null;
- if (this.listlock.rafile.length()>0) {
- ObjectInputStream is = new ObjectInputStream(new BufferedInputStream(
- new java.io.FileInputStream(filelist)));
+ if (this.fileLock.rafile.length()>0) {
+
+ ObjectInputStream is = new ObjectInputStream(fileLock.getBufferedInputStream(true));
Object o;
o=is.readObject();
if (o!=null) {
clients = (ClientHandle[]) o;
}
catch (Exception e) {
- System.err.println("Garbage in the clientHandle list "+this.filelist);
+ System.err.println("Garbage in the clientHandle list "+this.sessionFile);
}
}
}
return null;
}
/**
- * get the clientList from the file. May return false if lock failed!
+ * get the clientList from the file. May return null if lock failed!
* @return clientList
*/
public ClientHandle[] retrieveClientList() {
- if (lockList()) {
+ if (lockFile()) {
ClientHandle[] clients = retrieveClientHandles();
- unlockList();
+ unlockFile();
return clients;
}
return null;
}
-
+ /**
+ * get list from the locked ClientList.
+ * @param extantlock
+ * @return clientList or null if lock failed (or file was empty)
+ */
+ public ClientHandle[] retrieveClientList(Lock extantlock) {
+ if (lockFile(extantlock)) {
+ ClientHandle[] clients = retrieveClientHandles();
+ unlockFile();
+ return clients;
+ }
+ return null;
+ }
+ /**
+ * adds clientHandle me to the clientList under an existing lock extantLock.
+ * @param me
+ * @param extantLock
+ * @return client index in list or 0 if lock was invalid or addClient operation failed.
+ */
+ public int addClient(ClientHandle me, Lock extantLock) {
+ return addClient(me, true, extantLock);
+ }
+
+ /**
+ * adds clientHandle me to the clientList under an existing lock.
+ * @param me - clientHandle
+ * @param disambig - if true then add will fail if an identical clientHandle already exists
+ * @param extantLock - existing lock
+ * @return client index in list or 0 if addClient (or the lock) failed.
+ */
+
+ public int addClient(ClientHandle me, boolean disambig, Lock extantLock) {
+ if (lockFile(extantLock)) {
+ syncnum = addClient(me, disambig);
+ unlockFile();
+ return syncnum;
+ }
+ return 0;
+ }
+
/**
* adds the ClientHandle to the list - if it is not unique, then the
* ClientHandle object is modified to make it unique in the list. returns the
public int addClient(ClientHandle me) {
syncnum = addClient(me, true);
- unlockList();
+ unlockFile();
return syncnum;
}
/**
* removes 'me' from the session ClientList without complaint if 'me' isn't in the clientList already.
- * @param me
+ * @param me client handle to be removed
+ * @param clientlock existing lock passed from watcher.
*/
- public void removeClient(ClientHandle me) {
+ public void removeClient(ClientHandle me, Lock clientlock) {
int mynum=-1;
- if (lockList()) {
+ if (lockFile(clientlock)) {
ClientHandle[] clients = retrieveClientHandles();
if (clients != null) {
- if (clients[syncnum-1]!=me) {
+ if ((syncnum<=0 || syncnum>clients.length) || clients[syncnum-1]!=me) {
for (int i = 0, j = clients.length; i < j; i++)
if (clients[i].equals(me)) {
mynum=i;
throw new Error("Failed to write new clientList!"); // failed to put the clientList to disk.
}
}
- unlockList();
+ unlockFile();
} else {
- throw new Error("Couldn't get lock for "+((filelist==null) ? "Unitialised filelist in ClientsFile" : filelist.getAbsolutePath()));
+ throw new Error("Couldn't get lock for "+((sessionFile==null) ? "Unitialised sessionFile in ClientsFile" : sessionFile.getAbsolutePath()));
}
}
/**
*/
protected int addClient(ClientHandle me, boolean disambiguate) {
int newclient = 0;
- if (lockList()) {
+ if (lockFile()) {
ClientHandle[] clients = retrieveClientHandles();
if (me.getClientUrn()==null) {
// TODO: move this into ClientUrn as a standard form method.
}
return newclient;
}
-
+
/**
- * safely writes clients array to the file referred to by filelist.
+ * safely writes clients array to the file referred to by sessionFile.
*
* @param clients
* @return true if successful write. Throws Errors otherwise.
*/
protected boolean putClientList(ClientHandle[] clients) {
- if (lockList()) {
- File templist = null;
- try {
- templist = File.createTempFile(filelist.getName(),".old", filelist.getParentFile());
- FileOutputStream tos = new FileOutputStream(templist);
- tos.getChannel().transferFrom(listlock.rafile.getChannel(), 0,
- listlock.rafile.length());
- tos.close();
- } catch (FileNotFoundException e1) {
- System.err.println("Can't create temp file for clientlist");
- e1.printStackTrace(System.err);
- } catch (IOException e1) {
- System.err
- .println("Error when copying content to temp file for clientlist");
- e1.printStackTrace(System.err);
- }
+ if (lockFile()) {
+ File templist = backupSessionFile();
if (templist != null) {
try {
- listlock.rafile.setLength(0);
- ObjectOutputStream os = new ObjectOutputStream(
- new BufferedOutputStream(new FileOutputStream(this.filelist)));
+ // fileLock.rafile.setLength(0);
+ ObjectOutputStream os =
+ new ObjectOutputStream(fileLock.getBufferedOutputStream(true));
+
+// new BufferedOutputStream(new FileOutputStream(this.sessionFile)));
+ // new BufferedOutputStream(new FileOutputStream(this.fileLock.rafile.getFD())));
os.writeObject(clients);
- os.close();
+ os.close(); // close destroys lock!
// All done - remove the backup.
templist.delete();
templist = null;
} catch (Exception e) {
if (templist != null) {
System.err
- .println("Serious - problems writing to filelist. Backup in "
+ .println("Serious - problems writing to sessionFile. Backup in "
+ templist.getAbsolutePath());
e.printStackTrace(System.err);
}
}
} else {
throw new Error("Could not lock the clientList: "
- + ((filelist == null) ? "Unitialized ClientsFile"
- : " failed to get lock on " + filelist.getAbsolutePath()));
+ + ((sessionFile == null) ? "Unitialized ClientsFile"
+ : " failed to get lock on " + sessionFile.getAbsolutePath()));
}
// successful!
return true;
git://source.jalview.org / vamsas.git / blobdiff