moved IClientDocument implementation into the simpleclient package.

[vamsas.git] / src / org / vamsas / client / simpleclient / SessionFile.java

diff --git a/src/org/vamsas/client/simpleclient/SessionFile.java b/src/org/vamsas/client/simpleclient/SessionFile.java
index b43b1a9..30abd99 100644 (file)
--- a/src/org/vamsas/client/simpleclient/SessionFile.java
+++ b/src/org/vamsas/client/simpleclient/SessionFile.java
@@ -5,14 +5,17 @@ import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
 /**
  * Basic methods for classes handling locked IO on files 
  * monitored by all (simpleclient) clients in a vamsas session.
  * @author jimp
- *
+ *TODO: support non nio file locking capable systems
  */
 public class SessionFile {
-
+  private static Log log = LogFactory.getLog(SessionFile.class);
   protected File sessionFile;
   protected Lock fileLock = null;
 
@@ -55,8 +58,7 @@ public class SessionFile {
         return fileLock.isLocked();
       }
     } else
-      throw new Error(
-          "org.vamsas.client.simpleclient.SessionFile.lockFile called for non-initialised SessionFile!");
+      log.error("lockFile called for non-initialised SessionFile!");
   
     // no lock possible
     return false;
@@ -92,17 +94,30 @@ public class SessionFile {
             fileLock.rafile.length());
         tos.close();
       } catch (FileNotFoundException e1) {
-        System.err.println("Can't create temp file for "+sessionFile.getName());
-        e1.printStackTrace(System.err);
+        log.warn("Can't create temp file for "+sessionFile.getName(),e1);
         tempfile=null;
       } catch (IOException e1) {
-        System.err
-            .println("Error when copying content to temp file for "+sessionFile.getName());
-        e1.printStackTrace(System.err);
+        log.warn("Error when copying content to temp file for "+sessionFile.getName(),e1);
         tempfile=null;
       }
     }
     return tempfile;
   }
-
+  /**
+   * Replaces data in sessionFile with data from file handled by another sessionFile
+   * passes up any exceptions.
+   * @param newData source for new data
+   */
+  protected void updateFrom(Lock extantLock, SessionFile newData) throws IOException {
+    log.debug("Updating "+sessionFile.getAbsolutePath()+" from "+newData.sessionFile.getAbsolutePath());
+    if (newData==null)
+      throw new IOException("Null newData object.");
+    if (newData.sessionFile==null)
+      throw new IOException("Null SessionFile in newData.");
+      
+    lockFile(extantLock);  
+    newData.lockFile();
+    fileLock.rafile.getChannel().transferFrom(newData.fileLock.rafile.getChannel(), 0, 
+        newData.fileLock.rafile.length());
+  }
 }