changed semaphore implementation and session modified flag.

git-svn-id: https://svn.lifesci.dundee.ac.uk/svn/repository/trunk@185 be28352e-c001-0410-b1a7-c7978e42abec

diff --git a/src/org/vamsas/client/simpleclient/SimpleClient.java b/src/org/vamsas/client/simpleclient/SimpleClient.java
index daf3ca5..0445e2a 100644 (file)
--- a/src/org/vamsas/client/simpleclient/SimpleClient.java
+++ b/src/org/vamsas/client/simpleclient/SimpleClient.java
@@ -254,7 +254,7 @@ public class SimpleClient implements IClient {
     // Events.DOCUMENT_FINALIZEAPPDATA
     try {
       _session.writeVamsasDocument(location, vamlock);
-      _session.updateLastStoredStat();
+      _session.clearUnsavedFlag();
     } catch (Exception e) {
       log.warn("Exception whilst trying to store document in "+location,e);
     }
@@ -322,7 +322,7 @@ public class SimpleClient implements IClient {
       throw new Exception("Failed to start event generator thread - client cannot be instantiated.");
     }
     if (evgen.countHandlersFor(Events.DOCUMENT_CREATE)>0) {
-      //TODO: check vamsas document for presence of an AppData entry for this application
+      //TODO: is this application connecting to a newly created session document ?
       //evgen.raise(Events.DOCUMENT_CREATE);
     }
   }

diff --git a/src/org/vamsas/client/simpleclient/VamsasSession.java b/src/org/vamsas/client/simpleclient/VamsasSession.java
index 7971f57..4e6f430 100644 (file)
--- a/src/org/vamsas/client/simpleclient/VamsasSession.java
+++ b/src/org/vamsas/client/simpleclient/VamsasSession.java
@@ -15,9 +15,17 @@ import org.apache.log4j.FileAppender;
 import org.vamsas.client.ClientHandle;
 import org.vamsas.client.UserHandle;
 /**
- * Holds the file handlers and watchers for a session.
+ * Does all the IO operations for a SimpleClient instance accessing 
+ * a SimpleClient vamsas session.
  * 
- * TODO: delete the stuff below - prolly irrelevant now
+ * Basically, it defines the various standard names for the files 
+ * in the session directory (that maps to the sessionUrn), 
+ * provides constructors for the file handlers and watchers of 
+ * those file entities, and some higher level methods 
+ * to check and change the state flags for the session.
+ * 
+ * TODO: move the stuff below to the SimpleClientFactory documentation.
+ * much may not be valid now :
  * Vamsas client is intialised with a path to create live session directories. 
  * This path may contain a vamsas.properties file 
  * that sets additional parameters (otherwise client 
@@ -52,6 +60,9 @@ import org.vamsas.client.UserHandle;
  * During the session
  *  - Update watcher checks for file change - 
  * 
+ * Procedures for file based session message exchange
+ *  - session document modification flag
+ *    
  */
 
 public class VamsasSession {
@@ -62,11 +73,34 @@ public class VamsasSession {
    */
   public static final String CLOSEANDSAVE_FILE="stored.log";
   /**
-   * state of vamsas document when it was last stored outside the session directory
+   * session file storing the last_stored_stat data 
    */
-  protected long last_stored_stat[]=null;
-  protected void updateLastStoredStat() {
-    
+  public static final String MODIFIEDDOC_FILE="modified";
+
+  /**
+   * called to clear update flag after a successful offline storage event
+   */
+  protected void clearUnsavedFlag() {
+    SessionFlagFile laststored = new SessionFlagFile(new File(sessionDir, MODIFIEDDOC_FILE));
+    if (!laststored.clearFlag())
+      log.warn("Unsaved flag was not cleared for "+sessionDir);
+  }
+  /**
+   * called to indicate session document has been modified.
+   *
+   */
+  protected void setUnsavedFlag() {
+    SessionFlagFile laststored = new SessionFlagFile(new File(sessionDir, MODIFIEDDOC_FILE));
+    if (!laststored.setFlag())
+      log.warn("Couldn't set the Unsaved flag for "+sessionDir);
+  }
+  /**
+   * 
+   * @return true if session document has been modified since last offline storage event 
+   */
+  protected boolean getUnsavedFlag() {
+    SessionFlagFile laststored = new SessionFlagFile(new File(sessionDir, MODIFIEDDOC_FILE));
+    return laststored.checkFlag();
   }
   /**
    * log file location
@@ -79,7 +113,7 @@ public class VamsasSession {
    * @throws IOException
    */
   private void initLog() throws IOException {
-    // TODO: LATER: make dedicated appender format for session log.
+    // LATER: make dedicated appender format for session log.
     Appender app = slog.getAppender("SESSION_LOG");
     slog.addAppender(new FileAppender(app.getLayout(), new File(sessionDir, SESSION_LOG).getAbsolutePath()));
   }
@@ -170,20 +204,27 @@ public class VamsasSession {
   public FileWatcher getClientWatcher() {
     return new FileWatcher(clist.sessionFile);
   }
+  FileWatcher session_doc_watcher=null;
   /**
    * make a new watcher object for the vamsas Document
    * @return new ClientFile watcher instance
    */
   public FileWatcher getDocWatcher() {
+    if (session_doc_watcher==null)
+      return session_doc_watcher = new FileWatcher(vamArchive.sessionFile);
     return new FileWatcher(vamArchive.sessionFile);
   }
   FileWatcher store_doc_file=null;
   /**
    * make a new watcher object for the messages file
+   * (thread safe - keeps a reference to the first watcher)
    * @return new watcher instance
    */
   public FileWatcher getStoreWatcher() {
-    return store_doc_file = new FileWatcher(new File(CLOSEANDSAVE_FILE));
+    if (store_doc_file==null)
+      return store_doc_file = new FileWatcher(new File(CLOSEANDSAVE_FILE));
+    return new FileWatcher(new File(CLOSEANDSAVE_FILE));
+
   }
   /**
    * write to the StoreWatcher file to indicate that a storeDocumentRequest has been made.
@@ -230,7 +271,7 @@ public class VamsasSession {
         log.info("Trying to get lock for "+vamArchive.sessionFile);
     // TODO: LATER: decide if session archive provenance should be written in vamsasDocument file for this export.
     newdoc.updateFrom(extlock, vamArchive);
-    // TODO: SOON: fix use of updateFrom for file systems where locks cannot be made (because they don't have a lockManager, ie NFS/Unix, etc).
+    // LATER: LATER: fix use of updateFrom for file systems where locks cannot be made (because they don't have a lockManager, ie NFS/Unix, etc).
     vamArchive.unLock();
     newdoc.unlockFile();
     log.debug("Transfer complete.");