some enhancements to the access tracker (less synchronization)

git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@4812 6c8d7289-2bf4-0310-a012-ef5d649a1542

source/de/anomic/http/httpd.java

@@ -733,7 +733,7 @@ public final class httpd implements serverHandler {
         // reseting the empty request counter
         this.emptyRequestCount = 0;
         
-        // counting the amount of received requests within this permanent conneciton
+        // counting the amount of received requests within this permanent connection
         this.prop.setProperty(httpHeader.CONNECTION_PROP_KEEP_ALIVE_COUNT, Integer.toString(++this.keepAliveRequestCount));
         
         // setting the client-IP

source/de/anomic/server/serverAbstractSwitch.java

@@ -43,11 +43,11 @@ package de.anomic.server;
 import java.io.File;
 import java.io.IOException;
 import java.net.InetAddress;
-import java.util.ConcurrentModificationException;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Map;
 import java.util.TreeMap;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.LinkedBlockingQueue;
 
 import de.anomic.server.logging.serverLog;
@@ -68,7 +68,7 @@ public abstract class serverAbstractSwitch<E> implements serverSwitch<E> {
     private   HashMap<InetAddress, String>           authorization;
     private   TreeMap<String, serverBusyThread>      workerThreads;
     private   TreeMap<String, serverSwitchAction>    switchActions;
-    protected HashMap<String, TreeMap<Long, String>> accessTracker; // mappings from requesting host to an ArrayList of serverTrack-entries
+    protected ConcurrentHashMap<String, TreeMap<Long, String>> accessTracker; // mappings from requesting host to an ArrayList of serverTrack-entries
     private   LinkedBlockingQueue<E> cacheStack;
     
     public serverAbstractSwitch(File rootPath, String initPath, String configPath, boolean applyPro) {
@@ -148,7 +148,7 @@ public abstract class serverAbstractSwitch<E> implements serverSwitch<E> {
 
         // other settings
         authorization = new HashMap<InetAddress, String>();
-        accessTracker = new HashMap<String, TreeMap<Long, String>>();
+        accessTracker = new ConcurrentHashMap<String, TreeMap<Long, String>>();
 
         // init thread control
         workerThreads = new TreeMap<String, serverBusyThread>();
@@ -177,14 +177,10 @@ public abstract class serverAbstractSwitch<E> implements serverSwitch<E> {
         if (accessPath == null) accessPath="NULL";
         TreeMap<Long, String> access = accessTracker.get(host);
         if (access == null) access = new TreeMap<Long, String>();
-        synchronized (access) {
         access.put(new Long(System.currentTimeMillis()), accessPath);
 
         // write back to tracker
-            try {
         accessTracker.put(host, clearTooOldAccess(access));
-            } catch (ConcurrentModificationException e) {};
-        }
     }
     
     public TreeMap<Long, String> accessTrack(String host) {
@@ -192,10 +188,8 @@ public abstract class serverAbstractSwitch<E> implements serverSwitch<E> {
         
         TreeMap<Long, String> access = accessTracker.get(host);
         if (access == null) return null;
-        synchronized (access) {
         // clear too old entries
-            int oldsize = access.size();
-            if ((access = clearTooOldAccess(access)).size() != oldsize) {
+        if ((access = clearTooOldAccess(access)).size() != access.size()) {
             // write back to tracker
             if (access.size() == 0) {
                 accessTracker.remove(host);
@@ -206,7 +200,6 @@ public abstract class serverAbstractSwitch<E> implements serverSwitch<E> {
         
         return access;
     }
-    }
     
     private TreeMap<Long, String> clearTooOldAccess(TreeMap<Long, String> access) {
         return new TreeMap<Long, String>(access.tailMap(new Long(System.currentTimeMillis() - maxTrackingTime)));
@@ -215,9 +208,7 @@ public abstract class serverAbstractSwitch<E> implements serverSwitch<E> {
     public Iterator<String> accessHosts() {
         // returns an iterator of hosts in tracker (String)
     	HashMap<String, TreeMap<Long, String>> accessTrackerClone = new HashMap<String, TreeMap<Long, String>>();
-    	try {
     	accessTrackerClone.putAll(accessTracker);
-    	} catch (ConcurrentModificationException e) {}
     	return accessTrackerClone.keySet().iterator();
     }