--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/org/prevayler/implementation/NumberFileCleaner.java	Sat Mar 21 11:00:06 2009 +0000
@@ -0,0 +1,80 @@
+package org.prevayler.implementation;
+
+import org.dancres.blitz.txn.TxnManager;
+
+import java.io.File;
+import java.io.FileFilter;
+
+import java.util.Arrays;
+import java.util.logging.Level;
+
+/**
+   <p>Cleans up old log files and snapshots.  Helper class produced from a
+   NumberFileCreator which can be used by a programmer to clean up no longer
+   required log files and snapshots.  Not all deployments will want to use this
+   as some will wish to archive all such logs and snapshots for recovery
+   purposes or to satisfy certain legal requirements.</p>
+ */
+class NumberFileCleaner {
+    File theDirectory;
+
+    NumberFileCleaner(File aDirectory) {
+        theDirectory = aDirectory;
+    }
+
+    void clean() {
+        File[] myFiles = theDirectory.listFiles(new SnapshotFilter());
+
+        Arrays.sort(myFiles);
+
+        /*
+        for (int i = (myFiles.length -1); i >-1; i--) {
+            TxnManager.theLogger.log(Level.SEVERE, "Ordered: " + myFiles[i]);
+        }
+        */
+
+        int myLastSnapshot = findLastSnapshot(myFiles);
+
+        if (myLastSnapshot != -1) {
+            for (int i = (myLastSnapshot - 1); i > -1; i--) {
+                // TxnManager.theLogger.log(Level.SEVERE, "Delete: " + myFiles[i]);
+                myFiles[i].delete();
+            }
+        }
+    }
+
+    private int findLastSnapshot(File[] aFiles) {
+        for (int i = (aFiles.length - 1); i > -1; i--) {
+            File myFile = aFiles[i];
+            if (myFile.getName().endsWith("." +
+                                          NumberFileCreator.SNAPSHOT_SUFFIX)) {
+                return i;
+            }
+        }
+
+        return -1;
+    }
+
+    private static class SnapshotFilter implements FileFilter {
+        public boolean accept(File aFile) {
+            String myName = aFile.getName();
+
+            if ((aFile.isDirectory()) ||
+                ((!myName.endsWith("." +
+                                   NumberFileCreator.SNAPSHOT_SUFFIX)) &&
+                 (!myName.endsWith("." +
+                                   NumberFileCreator.LOGFILE_SUFFIX))))
+                return false;
+
+            try {
+                Long.parseLong(myName.substring(0,myName.indexOf('.')));
+
+                return true;
+            } catch (NumberFormatException nfx) {
+                return false;
+            }
+        }
+    }
+
+
+}