fixed bug with null node caching and groupby nodes.

src/helma/objectmodel/db/Node.java

@@ -329,6 +329,7 @@ public class Node implements INode, Serializable {
 	if (state == TRANSIENT)
 	    return; // no need to lock transient node
 	Transactor current = (Transactor) Thread.currentThread ();
+
 	if (!current.isActive ())
 	    throw new helma.framework.TimeoutException ();
 	if (state == INVALID) {
@@ -336,10 +337,12 @@ public class Node implements INode, Serializable {
 	    Thread.dumpStack ();
 	    throw new ConcurrencyException ("Node "+this+" was invalidated by another thread.");
 	}
+
 	if (lock != null && lock != current && lock.isAlive () && lock.isActive ()) {
 	    nmgr.logEvent ("Concurrency conflict for "+this+", lock held by "+lock);
 	    throw new ConcurrencyException ("Tried to modify "+this+" from two threads at the same time.");
 	}
+
 	current.visitNode (this);
 	lock = current;
     }
@@ -602,6 +605,9 @@ public class Node implements INode, Serializable {
     }
 
 
+    /**
+     * Get parent, retrieving it if necessary.
+     */
     public INode getParent () {
 
 	// check what's specified in the type.properties for this node.
@@ -646,6 +652,16 @@ public class Node implements INode, Serializable {
     }
 
 
+    /**
+     * Get parent, using cached info if it exists.
+     */
+    public Node getCachedParent () {
+	if (parentID == null)
+	    return null;
+	return nmgr.getNode (parentID, parentmap);
+    }
+
+
     /**
      *  INode-related
      */
@@ -948,6 +964,7 @@ public class Node implements INode, Serializable {
 	// need to query parent before releaseNode is called, since this may change the parent
 	// to the next option described in the type.properties _parent info
 	INode parent = n.getParent ();
+
 	releaseNode (n);
 
 	if (parent == this) {

src/helma/objectmodel/db/NodeManager.java

@@ -165,7 +165,7 @@ public final class NodeManager {
 	    if (node != null) {
 	        synchronized (cache) {
 	            Node oldnode = (Node) cache.put (node.getKey (), node);
-	            if (oldnode != null && oldnode.getState () != Node.INVALID) {
+	            if (oldnode != null && oldnode.getState () != Node.INVALID && oldnode != nullNode) {
 	                cache.put (node.getKey (), oldnode);
 	                node = oldnode;
 	            }
@@ -254,6 +254,7 @@ public final class NodeManager {
 	        }
 	    }
 	} else if (node == nullNode) {
+	    // the nullNode caches a null value, i.e. an object that doesn't exist
 	    return null;
 	} else {
 	    // update primary key in cache to keep it from being flushed, see above
@@ -454,7 +455,7 @@ public final class NodeManager {
 	}
 	// update may cause changes in the node's parent subnode array
 	if (node.isAnonymous()) {
-	    Node parent = (Node) node.getParent ();
+	    Node parent = node.getCachedParent ();
 	    if (parent != null)
 	        parent.lastSubnodeChange = System.currentTimeMillis ();
 	}
@@ -591,7 +592,14 @@ public final class NodeManager {
 	        qds.fetchRecords ();
 	        for (int i=0; i<qds.size (); i++) {
 	            Record rec = qds.getRecord (i);
-	            retval.addElement (rec.getValue (1).asString ());
+	            String kstr = rec.getValue (1).asString ();
+	            retval.addElement (kstr);
+	            // if these are groupby nodes, evict nullNode keys
+	            if (rel.groupby != null) {
+	                Key key = new Key ((String) null,  home.getKey ().getVirtualID (kstr));
+	                if (cache.get (key) == nullNode)
+	                    evictKey (key);
+	            }
 	        }
 
 	    } finally {

src/helma/objectmodel/db/Transactor.java

@@ -129,7 +129,6 @@ public class Transactor extends Thread {
 
 	for (Iterator i=nodes.values().iterator(); i.hasNext (); ) {
 	    Node node = (Node) i.next ();
-
 	    // update nodes in db
 	    int nstate = node.getState ();
 	    if (nstate == Node.NEW) {
@@ -137,12 +136,12 @@ public class Transactor extends Thread {
 	        nmgr.insertNode (nmgr.db, txn, node);
 	        node.setState (Node.CLEAN);
 	        ins++;
-	        nmgr.app.logEvent ("inserted: Node "+node.getName ()+"/"+node.getID ());
+	        nmgr.app.logEvent ("inserted: Node "+node.getPrototype ()+"/"+node.getID ());
 	    } else if (nstate == Node.MODIFIED) {
 	        nmgr.updateNode (nmgr.db, txn, node);
 	        node.setState (Node.CLEAN);
 	        upd++;
-	        nmgr.app.logEvent ("updated: Node "+node.getName ()+"/"+node.getID ());
+	        nmgr.app.logEvent ("updated: Node "+node.getPrototype ()+"/"+node.getID ());
 	    } else if (nstate == Node.DELETED) {
 	        // nmgr.app.logEvent ("deleted: "+node.getFullName ()+" ("+node.getName ()+")");
 	        nmgr.deleteNode (nmgr.db, txn, node);