enhanced synchronization in balancer

git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@2291 6c8d7289-2bf4-0310-a012-ef5d649a1542

source/de/anomic/plasma/plasmaCrawlBalancer.java

@@ -78,8 +78,10 @@ public class plasmaCrawlBalancer {
     }
     
     public void reset() {
+        synchronized (domainStacks) {
             stack = kelondroStack.reset(stack);
-        domainStacks = new HashMap();
+            domainStacks.clear();
+        }
     }
     
     public Iterator iterator() {
@@ -92,8 +94,9 @@ public class plasmaCrawlBalancer {
     }
     
     private int sizeDomainStacks() {
+        if (domainStacks == null) return 0;
         int sum = 0;
-        if (domainStacks != null) synchronized (domainStacks) {
+        synchronized (domainStacks) {
             Iterator i = domainStacks.values().iterator();
             while (i.hasNext()) sum += ((ArrayList) i.next()).size();
         }
@@ -119,8 +122,8 @@ public class plasmaCrawlBalancer {
         while (domainStacks.size() > 0) flushOnce();
     }
     
-    public synchronized void add(String domain, byte[] hash) throws IOException {
+    public void add(String domain, byte[] hash) throws IOException {
-        //stack.push(new byte[][]{hash});
+        synchronized (domainStacks) {
             ArrayList domainList = (ArrayList) domainStacks.get(domain);
             if (domainList == null) {
                 // create new list
@@ -131,6 +134,7 @@ public class plasmaCrawlBalancer {
                 // extend existent domain list
                 domainList.add(hash);
             }
+        }
         
         // check size of domainStacks and flush
         if ((domainStacks.size() > 20) || (sizeDomainStacks() > 400)) {
@@ -138,9 +142,10 @@ public class plasmaCrawlBalancer {
         }
     }
     
-    public synchronized Object[] /*String, byte[]*/ get() throws IOException {
+    public Object[] /*String, byte[]*/ get() throws IOException {
         // returns a pair of domain/hash from the stack
         // if the domain is unknown, a null/hash is returned
+        synchronized (domainStacks) {
             if (stack.size() > 0) {
                 return new Object[]{null, stack.pop().getColBytes(0)};
             } else if (domainStacks.size() > 0) {
@@ -150,16 +155,21 @@ public class plasmaCrawlBalancer {
                 return null;
             }
         }
+    }
     
-    public synchronized byte[] top(int dist) throws IOException {
+    public byte[] top(int dist) throws IOException {
         flushAll();
+        synchronized (domainStacks) {
             return stack.top(dist).getColBytes(0);
         }
+    }
     
     public void clear() throws IOException {
+        synchronized (domainStacks) {
             domainStacks.clear();
             stack.clear();
         }
+    }
     
     public class KeyIterator implements Iterator {