--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/org/dancres/blitz/entry/PrimaryLocatorImpl.java	Sat Mar 21 11:00:06 2009 +0000
@@ -0,0 +1,111 @@
+package org.dancres.blitz.entry;
+
+import java.io.IOException;
+
+import java.util.logging.Level;
+
+import com.sleepycat.je.Cursor;
+import com.sleepycat.je.DatabaseEntry;
+import com.sleepycat.je.DatabaseException;
+import com.sleepycat.je.OperationStatus;
+
+import org.dancres.blitz.oid.OID;
+import org.dancres.blitz.oid.OIDFactory;
+import org.dancres.blitz.mangler.MangledEntry;
+
+/**
+   TupleLocator implementation to be used on main index file which contains
+   oid and entry.
+ */
+class PrimaryLocatorImpl implements TupleLocator {
+    private MangledEntry theTemplate;
+    private int theReadahead;
+
+    private Cursor theCursor;
+    private boolean isFirst = true;
+
+    private DatabaseEntry theKey;
+    private DatabaseEntry theData;
+
+    /**
+       @param aCursor the cursor to use for iteration
+     */
+    PrimaryLocatorImpl(Cursor aCursor, MangledEntry aTemplate, int aReadahead) {
+        theCursor = aCursor;
+        theTemplate = aTemplate;
+        theReadahead = aReadahead;
+    }
+
+    /**
+       Invoke this to load the next matching Tuple.
+
+       @return <code>true</code> if there was a tuple, <code>false</code>
+       otherwise
+     */
+    public boolean fetchNext() throws IOException {
+        /*
+          The cursor will have been initialised whilst we decided which
+          field was best to search on which means it will already be pointed
+          at the first record so we must handle this case specially.  Note
+          that we only get created if the cursor actually contains records so
+          we don't need to do any testing here.
+        */
+        if (isFirst) {
+            loadNext(false);
+
+            isFirst = false;
+
+            return true;
+        } else {
+            return loadNext(true);
+        }
+    }
+
+    private boolean loadNext(boolean moveForward) throws IOException {
+        OperationStatus myResult;
+
+        try {
+            theKey = new DatabaseEntry();
+            theData = new DatabaseEntry();
+
+            if (moveForward)
+                myResult = theCursor.getNext(theKey, theData, null);
+            else
+                myResult = theCursor.getCurrent(theKey, theData, null);
+
+        } catch (DatabaseException aDbe) {
+            EntryStorage.theLogger.log(Level.SEVERE, "Got Dbe", aDbe);
+            throw new IOException("Dbe");
+        }
+
+        return (! myResult.equals(OperationStatus.NOTFOUND));
+    }
+
+    /**
+       @return the OID of the tuple just fetched with
+       <code>fetchNext</code>
+     */
+    public OID getOID() {
+        OID myResult = OIDFactory.newOID(theKey.getData());
+
+        return myResult;
+    }
+
+    /**
+       When you've finished with the TupleLocator instance, call release.
+     */
+    public void release() throws IOException {
+        releaseImpl();
+
+        Readahead.get().add(theTemplate, theReadahead);
+    }
+
+    private void releaseImpl() throws IOException {
+        try {
+            theCursor.close();
+        } catch (DatabaseException aDbe) {
+            EntryStorage.theLogger.log(Level.SEVERE, "Got Dbe", aDbe);
+            throw new IOException("Dbe");
+        }
+    }
+}