*) Automatic Reset of Stack Crawler DB on startup errors

See: http://www.yacy-forum.de/viewtopic.php?t=1432

git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@1045 6c8d7289-2bf4-0310-a012-ef5d649a1542

source/de/anomic/plasma/plasmaCrawlStacker.java

@@ -60,6 +60,7 @@ import org.apache.commons.pool.impl.GenericObjectPool;
 
 import de.anomic.data.robotsParser;
 import de.anomic.http.httpc;
+import de.anomic.kelondro.kelondroException;
 import de.anomic.kelondro.kelondroTree;
 import de.anomic.kelondro.kelondroRecords.Node;
 import de.anomic.server.serverCodings;
@@ -467,7 +468,7 @@ public final class plasmaCrawlStacker {
         private final serverSemaphore readSync;
         private final serverSemaphore writeSync;
         private final LinkedList urlEntryHashCache;
-        private final kelondroTree urlEntryCache;
+        private kelondroTree urlEntryCache;
         
         public stackCrawlQueue(File cacheStacksPath, int bufferkb) throws IOException  {
             // init the read semaphore
@@ -486,7 +487,7 @@ public final class plasmaCrawlStacker {
             if (cacheFile.exists()) {
                 // open existing cache
                 this.urlEntryCache = new kelondroTree(cacheFile, bufferkb * 0x400);
-                
+                try {
                     // loop through the list and fill the messageList with url hashs
                     Iterator iter = this.urlEntryCache.nodeIterator(true,false);
                     Node n;
@@ -500,6 +501,15 @@ public final class plasmaCrawlStacker {
                         this.urlEntryHashCache.add(urlHash);
                         this.readSync.V();
                     }
+                } catch (kelondroException e) {
+                    /* if we have an error, we start with a fresh database */
+                    plasmaCrawlStacker.this.log.logSevere("Unable to initialize crawl stacker queue. Reseting DB.\n",e);
+                    
+                    // deleting old db and creating a new db
+                    try {this.urlEntryCache.close();}catch(Exception ex){}
+                    cacheFile.delete();
+                    this.urlEntryCache = new kelondroTree(cacheFile, bufferkb * 0x400, plasmaCrawlNURL.ce);
+                }
             } else {
                 // create new cache
                 cacheFile.getParentFile().mkdirs();