improve WallFilter

src/main/java/com/alibaba/druid/wall/WallDenyStat.java

@@ -1,19 +1,46 @@
 package com.alibaba.druid.wall;
 
+import java.util.Date;
 import java.util.concurrent.atomic.AtomicLongFieldUpdater;
 
 public class WallDenyStat {
 
     private volatile long                             denyCount;
 
-    final static AtomicLongFieldUpdater<WallDenyStat> denyCountUpdater = AtomicLongFieldUpdater.newUpdater(WallDenyStat.class,
-                                                                                                           "denyCount");
+    private volatile long                             lastDenyTimeMillis;
+
+    private volatile long                             resetCount;
+
+    final static AtomicLongFieldUpdater<WallDenyStat> denyCountUpdater  = AtomicLongFieldUpdater.newUpdater(WallDenyStat.class,
+                                                                                                            "denyCount");
+
+    final static AtomicLongFieldUpdater<WallDenyStat> resetCountUpdater = AtomicLongFieldUpdater.newUpdater(WallDenyStat.class,
+                                                                                                            "resetCount");
 
     public long incrementAndGetDenyCount() {
+        lastDenyTimeMillis = System.currentTimeMillis();
         return denyCountUpdater.incrementAndGet(this);
     }
 
     public long getDenyCount() {
         return denyCount;
     }
+
+    public Date getLastDenyTime() {
+        if (lastDenyTimeMillis <= 0) {
+            return null;
+        }
+        return new Date(lastDenyTimeMillis);
+    }
+
+    public void reset() {
+        lastDenyTimeMillis = 0;
+        denyCount = 0;
+        resetCountUpdater.incrementAndGet(this);
+    }
+
+    public long getResetCount() {
+        return this.resetCount;
+    }
+
 }