cells: Refactor cloning of CellMessage and CellPath

Target: trunk
Require-notes: no
Require-book: no
Acked-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
Acked-by: Paul Millar <paul.millar@desy.de>
Patch: https://rb.dcache.org/r/8133/

modules/cells/src/main/java/dmg/cells/nucleus/CellExceptionMessage.java

@@ -13,18 +13,8 @@ public CellExceptionMessage(CellPath addr, NoRouteToCellException msg)
         super(addr, msg);
     }
 
-    private CellExceptionMessage()
-    {
-    }
-
     public NoRouteToCellException getException()
     {
         return (NoRouteToCellException) getMessageObject();
     }
-
-    @Override
-    protected CellMessage cloneWithoutFields()
-    {
-        return new CellExceptionMessage();
-    }
 }

modules/cells/src/main/java/dmg/cells/nucleus/CellMessage.java

@@ -1,5 +1,7 @@
 package dmg.cells.nucleus ;
 
+import com.google.common.base.Throwables;
+
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
@@ -47,7 +49,7 @@ public class CellMessage implements Cloneable , Serializable {
 
   public CellMessage( CellPath addr , Serializable msg ){
 
-     _destination  = (CellPath) addr.clone();
+     _destination  = addr.clone();
      _message      = msg ;
      _source       = new CellPath() ;
      _creationTime = System.currentTimeMillis() ;
@@ -136,40 +138,42 @@ public CellMessage()
         _messageStream = null;
     }
 
-    protected CellMessage cloneWithoutFields()
-    {
-        return new CellMessage();
-    }
-
-    protected CellMessage cloneWithoutPayload()
+    /**
+     * The method does not copy the message object - only the encoded message
+     * stream (if any).
+     */
+    @Override
+    public CellMessage clone()
     {
-        CellMessage copy = cloneWithoutFields();
-        copy._destination = (CellPath) _destination.clone();
-        copy._source = (CellPath) _source.clone();
-        copy._creationTime = _creationTime;
-        copy._receivedAt = _receivedAt;
-        copy._umid = _umid;    // UOID is immutable
-        copy._lastUmid = _lastUmid;
-        copy._isPersistent = _isPersistent;
-        copy._session = _session;
-        copy._ttl = _ttl;
-        return copy;
+        try {
+            CellMessage copy = (CellMessage) super.clone();
+            copy._destination = _destination.clone();
+            if (_source != null) {
+                copy._source = _source.clone();
+            }
+            copy._messageStream = _messageStream;
+            return copy;
+        } catch (CloneNotSupportedException e) {
+            throw Throwables.propagate(e);
+        }
     }
 
     public CellMessage encode() throws SerializationException
     {
         checkState(_mode == ORIGINAL_MODE);
-        CellMessage encoded = cloneWithoutPayload();
+        CellMessage encoded = clone();
         encoded._mode = STREAM_MODE;
+        encoded._message = null;
         encoded._messageStream = encode(_message);
         return encoded;
     }
 
     public CellMessage decode() throws SerializationException
     {
         checkState(_mode == STREAM_MODE);
-        CellMessage decoded = cloneWithoutPayload();
+        CellMessage decoded = clone();
         decoded._mode = ORIGINAL_MODE;
+        decoded._messageStream = null;
         decoded._message = decode(_messageStream);
         return decoded;
     }

modules/cells/src/main/java/dmg/cells/nucleus/CellPath.java

@@ -98,7 +98,7 @@ public synchronized void add(String path)
    }
 
    @Override
-   public synchronized Object clone()
+   public synchronized CellPath clone()
    {
        return new CellPath(_position, Lists.newArrayList(_list));
    }

modules/cells/src/main/java/dmg/cells/services/multicaster/BroadcastCell.java

@@ -458,7 +458,7 @@ private synchronized void forwardMessage( CellMessage message , String classEven
         List<Entry> list = new ArrayList<>() ;
         CellPath  dest = message.getDestinationPath() ;
         for (Map.Entry<CellAddressCore, Entry> mapentry: map.entrySet()) {
-            CellPath origin = (CellPath) dest.clone();
+            CellPath origin = dest.clone();
             Entry entry = mapentry.getValue();
             if (!entry.isValid()) {
                 list.add(entry);

modules/cells/src/main/java/dmg/cells/services/multicaster/BroadcastEventCommandMessage.java

@@ -24,10 +24,10 @@ public BroadcastEventCommandMessage( String eventClass ){
     }
     public BroadcastEventCommandMessage(String eventClass , CellPath target ) {
         _eventClass = eventClass ;
-        _target = target != null ? (CellPath)target.clone() : null ;
+        _target = target != null ? target.clone() : null ;
     }
     public CellPath getTarget(){
-        return _target == null ? null : (CellPath)_target.clone() ;
+        return _target == null ? null : _target.clone();
     }
     public String getEventClass(){ return _eventClass ; }
     public String toString(){

modules/cells/src/main/java/dmg/cells/services/multicaster/MulticastCell.java

@@ -110,7 +110,7 @@ public MulticastCell( String name , String args )
    @Override
    public synchronized void messageArrived( CellMessage message ){
        Object   obj  = message.getMessageObject() ;
-       CellPath path = (CellPath)(message.getSourcePath().clone()) ;
+       CellPath path = message.getSourcePath().clone();
 
        if( obj instanceof NoRouteToCellException ){
           synchronized( _ioLock ){

modules/dcache/src/main/java/diskCacheV111/services/FileHoppingManager.java

@@ -464,8 +464,7 @@ public void messageArrived( CellMessage message ){
                  replicate.setProtocolInfo(info);
 
                  try {
-                     sendMessage(new CellMessage((CellPath) path
-                             .clone(), replicate));
+                     sendMessage(new CellMessage(path.clone(), replicate));
                  } catch (RuntimeException ee) {
                      _log.warn("Problem : couldn't forward message to : " + entry._path + " : " + ee);
                  }

modules/dcache/src/main/java/org/dcache/pool/migration/MigrationModuleServer.java

@@ -123,8 +123,7 @@ public void setPoolMode(PoolV2Mode mode)
             throw new LockedCacheException("Target file is busy");
         }
 
-        Request request =
-            new Request((CellPath)envelope.getSourcePath().clone(), message);
+        Request request = new Request(envelope.getSourcePath().clone(), message);
         _requests.put(request.getUUID(), request);
         request.start();
 

modules/dcache/src/main/java/org/dcache/util/Transfer.java

@@ -892,8 +892,7 @@ public void startMover(String queue, long timeout)
             /* As always, PoolIoFileMessage has to be sent via the
              * PoolManager (which could be the SpaceManager).
              */
-            CellPath poolPath =
-                (CellPath) _poolManager.getDestinationPath().clone();
+            CellPath poolPath = _poolManager.getDestinationPath().clone();
             poolPath.add(getPoolAddress());
 
             setMoverId(_pool.sendAndWait(poolPath, message, timeout).getMoverId());