diff --git a/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/base/LeapArray.java b/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/base/LeapArray.java
index a80946af..f3469161 100755
--- a/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/base/LeapArray.java
+++ b/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/base/LeapArray.java
@@ -18,10 +18,13 @@ package com.alibaba.csp.sentinel.slots.statistic.base;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.atomic.AtomicReferenceArray;
+import java.util.concurrent.locks.ReentrantLock;
 
 import com.alibaba.csp.sentinel.util.TimeUtil;
 
 /**
+ * Basic data structure for statistic metrics.
+ *
  * @param <T> type of data wrapper
  * @author jialiang.linjl
  * @author Eric Zhao
@@ -32,27 +35,86 @@ public abstract class LeapArray<T> {
     protected int sampleCount;
     protected int intervalInMs;
 
-    protected AtomicReferenceArray<WindowWrap<T>> array;
+    protected final AtomicReferenceArray<WindowWrap<T>> array;
+
+    private final ReentrantLock updateLock = new ReentrantLock();
 
     public LeapArray(int windowLength, int intervalInSec) {
         this.windowLength = windowLength;
-        this.sampleCount = intervalInSec * 1000 / windowLength;
         this.intervalInMs = intervalInSec * 1000;
+        this.sampleCount = intervalInMs / windowLength;
 
         this.array = new AtomicReferenceArray<WindowWrap<T>>(sampleCount);
     }
 
+    /**
+     * Get the window at current timestamp.
+     *
+     * @return the window at current timestamp
+     */
     public WindowWrap<T> currentWindow() {
         return currentWindow(TimeUtil.currentTimeMillis());
     }
 
+    /**
+     * Create a new bucket.
+     *
+     * @return the new empty bucket
+     */
+    public abstract T newEmptyBucket();
+
+    /**
+     * Reset current window to provided start time and reset all counters.
+     *
+     * @param startTime  the start time of the window
+     * @param windowWrap current window
+     * @return new clean window wrap
+     */
+    protected abstract WindowWrap<T> resetWindowTo(WindowWrap<T> windowWrap, long startTime);
+
     /**
      * Get window at provided timestamp.
      *
      * @param time a valid timestamp
      * @return the window at provided timestamp
      */
-    abstract public WindowWrap<T> currentWindow(long time);
+    public WindowWrap<T> currentWindow(long time) {
+        long timeId = time / windowLength;
+        // Calculate current index.
+        int idx = (int)(timeId % array.length());
+
+        // Cut the time to current window start.
+        time = time - time % windowLength;
+
+        while (true) {
+            WindowWrap<T> old = array.get(idx);
+            if (old == null) {
+                WindowWrap<T> window = new WindowWrap<T>(windowLength, time, newEmptyBucket());
+                if (array.compareAndSet(idx, null, window)) {
+                    return window;
+                } else {
+                    Thread.yield();
+                }
+            } else if (time == old.windowStart()) {
+                return old;
+            } else if (time > old.windowStart()) {
+                if (updateLock.tryLock()) {
+                    try {
+                        // if (old is deprecated) then [LOCK] resetTo currentTime.
+                        return resetWindowTo(old, time);
+                    } finally {
+                        updateLock.unlock();
+                    }
+                } else {
+                    Thread.yield();
+                }
+
+            } else if (time < old.windowStart()) {
+                // Cannot go through here.
+                return new WindowWrap<T>(windowLength, time, newEmptyBucket());
+            }
+        }
+    }
 
     public WindowWrap<T> getPreviousWindow(long time) {
         long timeId = (time - windowLength) / windowLength;
@@ -87,16 +149,12 @@ public abstract class LeapArray<T> {
         return old.value();
     }
 
-    AtomicReferenceArray<WindowWrap<T>> array() {
-        return array;
-    }
-
     private boolean isWindowDeprecated(WindowWrap<T> windowWrap) {
         return TimeUtil.currentTimeMillis() - windowWrap.windowStart() >= intervalInMs;
     }
 
     public List<WindowWrap<T>> list() {
-        ArrayList<WindowWrap<T>> result = new ArrayList<WindowWrap<T>>();
+        List<WindowWrap<T>> result = new ArrayList<WindowWrap<T>>();
 
         for (int i = 0; i < array.length(); i++) {
             WindowWrap<T> windowWrap = array.get(i);
@@ -110,7 +168,7 @@ public abstract class LeapArray<T> {
     }
 
     public List<T> values() {
-        ArrayList<T> result = new ArrayList<T>();
+        List<T> result = new ArrayList<T>();
 
         for (int i = 0; i < array.length(); i++) {
             WindowWrap<T> windowWrap = array.get(i);
diff --git a/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/base/Window.java b/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/base/MetricBucket.java
similarity index 96%
rename from sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/base/Window.java
rename to sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/base/MetricBucket.java
index e5a87b04..eb5c75ce 100755
--- a/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/base/Window.java
+++ b/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/base/MetricBucket.java
@@ -23,7 +23,7 @@ import com.alibaba.csp.sentinel.Constants;
  * @author jialiang.linjl
  * @author Eric Zhao
  */
-public class Window {
+public class MetricBucket {
 
     private final LongAdder pass = new LongAdder();
     private final LongAdder block = new LongAdder();
@@ -33,7 +33,7 @@ public class Window {
 
     private volatile long minRt;
 
-    public Window() {
+    public MetricBucket() {
         initMinRt();
     }
 
@@ -46,7 +46,7 @@ public class Window {
      *
      * @return new clean window
      */
-    public Window reset() {
+    public MetricBucket reset() {
         pass.reset();
         block.reset();
         exception.reset();
diff --git a/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/metric/ArrayMetric.java b/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/metric/ArrayMetric.java
index 433a681d..b7df1efa 100755
--- a/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/metric/ArrayMetric.java
+++ b/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/metric/ArrayMetric.java
@@ -20,27 +20,27 @@ import java.util.List;
 
 import com.alibaba.csp.sentinel.Constants;
 import com.alibaba.csp.sentinel.node.metric.MetricNode;
-import com.alibaba.csp.sentinel.slots.statistic.base.Window;
+import com.alibaba.csp.sentinel.slots.statistic.base.MetricBucket;
 import com.alibaba.csp.sentinel.slots.statistic.base.WindowWrap;
 
 /**
- * The basic metric class in Sentinel using a {@link WindowLeapArray} internal.
+ * The basic metric class in Sentinel using a {@link MetricsLeapArray} internal.
  *
  * @author jialiang.linjl
  * @author Eric Zhao
  */
 public class ArrayMetric implements Metric {
 
-    private final WindowLeapArray data;
+    private final MetricsLeapArray data;
 
     public ArrayMetric(int windowLength, int interval) {
-        this.data = new WindowLeapArray(windowLength, interval);
+        this.data = new MetricsLeapArray(windowLength, interval);
     }
 
     /**
      * For unit test.
      */
-    public ArrayMetric(WindowLeapArray array) {
+    public ArrayMetric(MetricsLeapArray array) {
         this.data = array;
     }
 
@@ -49,8 +49,8 @@ public class ArrayMetric implements Metric {
         data.currentWindow();
         long success = 0;
 
-        List<Window> list = data.values();
-        for (Window window : list) {
+        List<MetricBucket> list = data.values();
+        for (MetricBucket window : list) {
             success += window.success();
         }
         return success;
@@ -61,8 +61,8 @@ public class ArrayMetric implements Metric {
         data.currentWindow();
         long success = 0;
 
-        List<Window> list = data.values();
-        for (Window window : list) {
+        List<MetricBucket> list = data.values();
+        for (MetricBucket window : list) {
             if (window.success() > success) {
                 success = window.success();
             }
@@ -74,8 +74,8 @@ public class ArrayMetric implements Metric {
     public long exception() {
         data.currentWindow();
         long exception = 0;
-        List<Window> list = data.values();
-        for (Window window : list) {
+        List<MetricBucket> list = data.values();
+        for (MetricBucket window : list) {
             exception += window.exception();
         }
         return exception;
@@ -85,8 +85,8 @@ public class ArrayMetric implements Metric {
     public long block() {
         data.currentWindow();
         long block = 0;
-        List<Window> list = data.values();
-        for (Window window : list) {
+        List<MetricBucket> list = data.values();
+        for (MetricBucket window : list) {
             block += window.block();
         }
         return block;
@@ -96,9 +96,9 @@ public class ArrayMetric implements Metric {
     public long pass() {
         data.currentWindow();
         long pass = 0;
-        List<Window> list = data.values();
+        List<MetricBucket> list = data.values();
 
-        for (Window window : list) {
+        for (MetricBucket window : list) {
             pass += window.pass();
         }
         return pass;
@@ -108,8 +108,8 @@ public class ArrayMetric implements Metric {
     public long rt() {
         data.currentWindow();
         long rt = 0;
-        List<Window> list = data.values();
-        for (Window window : list) {
+        List<MetricBucket> list = data.values();
+        for (MetricBucket window : list) {
             rt += window.rt();
         }
         return rt;
@@ -119,8 +119,8 @@ public class ArrayMetric implements Metric {
     public long minRt() {
         data.currentWindow();
         long rt = Constants.TIME_DROP_VALVE;
-        List<Window> list = data.values();
-        for (Window window : list) {
+        List<MetricBucket> list = data.values();
+        for (MetricBucket window : list) {
             if (window.minRt() < rt) {
                 rt = window.minRt();
             }
@@ -133,7 +133,7 @@ public class ArrayMetric implements Metric {
     public List<MetricNode> details() {
         List<MetricNode> details = new ArrayList<MetricNode>();
         data.currentWindow();
-        for (WindowWrap<Window> window : data.list()) {
+        for (WindowWrap<MetricBucket> window : data.list()) {
             if (window == null) {
                 continue;
             }
@@ -156,38 +156,38 @@ public class ArrayMetric implements Metric {
     }
 
     @Override
-    public Window[] windows() {
+    public MetricBucket[] windows() {
         data.currentWindow();
-        return data.values().toArray(new Window[data.values().size()]);
+        return data.values().toArray(new MetricBucket[data.values().size()]);
     }
 
     @Override
     public void addException() {
-        WindowWrap<Window> wrap = data.currentWindow();
+        WindowWrap<MetricBucket> wrap = data.currentWindow();
         wrap.value().addException();
     }
 
     @Override
     public void addBlock() {
-        WindowWrap<Window> wrap = data.currentWindow();
+        WindowWrap<MetricBucket> wrap = data.currentWindow();
         wrap.value().addBlock();
     }
 
     @Override
     public void addSuccess() {
-        WindowWrap<Window> wrap = data.currentWindow();
+        WindowWrap<MetricBucket> wrap = data.currentWindow();
         wrap.value().addSuccess();
     }
 
     @Override
     public void addPass() {
-        WindowWrap<Window> wrap = data.currentWindow();
+        WindowWrap<MetricBucket> wrap = data.currentWindow();
         wrap.value().addPass();
     }
 
     @Override
     public void addRT(long rt) {
-        WindowWrap<Window> wrap = data.currentWindow();
+        WindowWrap<MetricBucket> wrap = data.currentWindow();
         wrap.value().addRT(rt);
     }
 
@@ -196,7 +196,7 @@ public class ArrayMetric implements Metric {
         data.currentWindow();
         StringBuilder sb = new StringBuilder();
         sb.append(Thread.currentThread().getId()).append("_");
-        for (WindowWrap<Window> windowWrap : data.list()) {
+        for (WindowWrap<MetricBucket> windowWrap : data.list()) {
 
             sb.append(windowWrap.windowStart()).append(":").append(windowWrap.value().pass()).append(":")
                 .append(windowWrap.value().block());
@@ -208,7 +208,7 @@ public class ArrayMetric implements Metric {
 
     @Override
     public long previousWindowBlock() {
-        WindowWrap<Window> wrap = data.currentWindow();
+        WindowWrap<MetricBucket> wrap = data.currentWindow();
         wrap = data.getPreviousWindow();
         if (wrap == null) {
             return 0;
@@ -218,12 +218,11 @@ public class ArrayMetric implements Metric {
 
     @Override
     public long previousWindowPass() {
-        WindowWrap<Window> wrap = data.currentWindow();
+        WindowWrap<MetricBucket> wrap = data.currentWindow();
         wrap = data.getPreviousWindow();
         if (wrap == null) {
             return 0;
         }
         return wrap.value().pass();
     }
-
 }
diff --git a/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/metric/Metric.java b/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/metric/Metric.java
index fc56bf9e..3a41e4e6 100755
--- a/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/metric/Metric.java
+++ b/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/metric/Metric.java
@@ -18,7 +18,7 @@ package com.alibaba.csp.sentinel.slots.statistic.metric;
 import java.util.List;
 
 import com.alibaba.csp.sentinel.node.metric.MetricNode;
-import com.alibaba.csp.sentinel.slots.statistic.base.Window;
+import com.alibaba.csp.sentinel.slots.statistic.base.MetricBucket;
 
 /**
  * Represents a basic structure recording invocation metrics of protected resources.
@@ -79,7 +79,7 @@ public interface Metric {
      *
      * @return window metric array
      */
-    Window[] windows();
+    MetricBucket[] windows();
 
     /**
      * Increment by one the current exception count.
diff --git a/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/metric/MetricsLeapArray.java b/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/metric/MetricsLeapArray.java
new file mode 100755
index 00000000..0c2dcb86
--- /dev/null
+++ b/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/metric/MetricsLeapArray.java
@@ -0,0 +1,45 @@
+/*
+ * Copyright 1999-2018 Alibaba Group Holding Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.alibaba.csp.sentinel.slots.statistic.metric;
+
+import com.alibaba.csp.sentinel.slots.statistic.base.LeapArray;
+import com.alibaba.csp.sentinel.slots.statistic.base.MetricBucket;
+import com.alibaba.csp.sentinel.slots.statistic.base.WindowWrap;
+
+/**
+ * The fundamental data structure for metric statistics in a time window.
+ *
+ * @author jialiang.linjl
+ * @author Eric Zhao
+ */
+public class MetricsLeapArray extends LeapArray<MetricBucket> {
+
+    public MetricsLeapArray(int windowLengthInMs, int intervalInSec) {
+        super(windowLengthInMs, intervalInSec);
+    }
+
+    @Override
+    public MetricBucket newEmptyBucket() {
+        return new MetricBucket();
+    }
+
+    @Override
+    protected WindowWrap<MetricBucket> resetWindowTo(WindowWrap<MetricBucket> w, long startTime) {
+        w.resetTo(startTime);
+        w.value().reset();
+        return w;
+    }
+}
diff --git a/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/metric/WindowLeapArray.java b/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/metric/WindowLeapArray.java
deleted file mode 100755
index 82a94554..00000000
--- a/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/metric/WindowLeapArray.java
+++ /dev/null
@@ -1,88 +0,0 @@
-/*
- * Copyright 1999-2018 Alibaba Group Holding Ltd.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.alibaba.csp.sentinel.slots.statistic.metric;
-
-import java.util.concurrent.locks.ReentrantLock;
-
-import com.alibaba.csp.sentinel.slots.statistic.base.LeapArray;
-import com.alibaba.csp.sentinel.slots.statistic.base.Window;
-import com.alibaba.csp.sentinel.slots.statistic.base.WindowWrap;
-
-/**
- * The fundamental data structure for metric statistics in a time window.
- *
- * @author jialiang.linjl
- * @author Eric Zhao
- */
-public class WindowLeapArray extends LeapArray<Window> {
-
-    public WindowLeapArray(int windowLengthInMs, int intervalInSec) {
-        super(windowLengthInMs, intervalInSec);
-    }
-
-    private ReentrantLock addLock = new ReentrantLock();
-
-    /**
-     * Reset current window to provided start time and reset all counters.
-     *
-     * @param startTime the start time of the window
-     * @return new clean window wrap
-     */
-    private WindowWrap<Window> resetWindowTo(WindowWrap<Window> w, long startTime) {
-        w.resetTo(startTime);
-        w.value().reset();
-        return w;
-    }
-
-    @Override
-    public WindowWrap<Window> currentWindow(long time) {
-        long timeId = time / windowLength;
-        // Calculate current index.
-        int idx = (int)(timeId % array.length());
-
-        // Cut the time to current window start.
-        time = time - time % windowLength;
-
-        while (true) {
-            WindowWrap<Window> old = array.get(idx);
-            if (old == null) {
-                WindowWrap<Window> window = new WindowWrap<Window>(windowLength, time, new Window());
-                if (array.compareAndSet(idx, null, window)) {
-                    return window;
-                } else {
-                    Thread.yield();
-                }
-            } else if (time == old.windowStart()) {
-                return old;
-            } else if (time > old.windowStart()) {
-                if (addLock.tryLock()) {
-                    try {
-                        // if (old is deprecated) then [LOCK] resetTo currentTime.
-                        return resetWindowTo(old, time);
-                    } finally {
-                        addLock.unlock();
-                    }
-                } else {
-                    Thread.yield();
-                }
-
-            } else if (time < old.windowStart()) {
-                // Cannot go through here.
-                return new WindowWrap<Window>(windowLength, time, new Window());
-            }
-        }
-    }
-}
diff --git a/sentinel-core/src/test/java/com/alibaba/csp/sentinel/base/metric/ArrayMetricTest.java b/sentinel-core/src/test/java/com/alibaba/csp/sentinel/base/metric/ArrayMetricTest.java
index 8bfbff4c..02e33732 100755
--- a/sentinel-core/src/test/java/com/alibaba/csp/sentinel/base/metric/ArrayMetricTest.java
+++ b/sentinel-core/src/test/java/com/alibaba/csp/sentinel/base/metric/ArrayMetricTest.java
@@ -19,10 +19,10 @@ import java.util.ArrayList;
 
 import org.junit.Test;
 
-import com.alibaba.csp.sentinel.slots.statistic.base.Window;
+import com.alibaba.csp.sentinel.slots.statistic.base.MetricBucket;
 import com.alibaba.csp.sentinel.slots.statistic.base.WindowWrap;
 import com.alibaba.csp.sentinel.slots.statistic.metric.ArrayMetric;
-import com.alibaba.csp.sentinel.slots.statistic.metric.WindowLeapArray;
+import com.alibaba.csp.sentinel.slots.statistic.metric.MetricsLeapArray;
 
 import static org.junit.Assert.*;
 
@@ -40,10 +40,10 @@ public class ArrayMetricTest {
 
     @Test
     public void testOperateArrayMetric() {
-        WindowLeapArray leapArray = mock(WindowLeapArray.class);
-        final WindowWrap<Window> windowWrap = new WindowWrap<Window>(windowLengthInMs, 0, new Window());
+        MetricsLeapArray leapArray = mock(MetricsLeapArray.class);
+        final WindowWrap<MetricBucket> windowWrap = new WindowWrap<MetricBucket>(windowLengthInMs, 0, new MetricBucket());
         when(leapArray.currentWindow()).thenReturn(windowWrap);
-        when(leapArray.values()).thenReturn(new ArrayList<Window>() {{ add(windowWrap.value()); }});
+        when(leapArray.values()).thenReturn(new ArrayList<MetricBucket>() {{ add(windowWrap.value()); }});
 
         ArrayMetric metric = new ArrayMetric(leapArray);
 
diff --git a/sentinel-core/src/test/java/com/alibaba/csp/sentinel/base/metric/WindowLeapArrayTest.java b/sentinel-core/src/test/java/com/alibaba/csp/sentinel/base/metric/MetricsLeapArrayTest.java
similarity index 74%
rename from sentinel-core/src/test/java/com/alibaba/csp/sentinel/base/metric/WindowLeapArrayTest.java
rename to sentinel-core/src/test/java/com/alibaba/csp/sentinel/base/metric/MetricsLeapArrayTest.java
index 63a60c03..735838e4 100755
--- a/sentinel-core/src/test/java/com/alibaba/csp/sentinel/base/metric/WindowLeapArrayTest.java
+++ b/sentinel-core/src/test/java/com/alibaba/csp/sentinel/base/metric/MetricsLeapArrayTest.java
@@ -21,30 +21,30 @@ import java.util.List;
 import java.util.Set;
 import java.util.concurrent.CountDownLatch;
 
+import com.alibaba.csp.sentinel.slots.statistic.base.MetricBucket;
 import com.alibaba.csp.sentinel.util.TimeUtil;
-import com.alibaba.csp.sentinel.slots.statistic.base.Window;
 import com.alibaba.csp.sentinel.slots.statistic.base.WindowWrap;
-import com.alibaba.csp.sentinel.slots.statistic.metric.WindowLeapArray;
+import com.alibaba.csp.sentinel.slots.statistic.metric.MetricsLeapArray;
 
 import org.junit.Test;
 
 import static org.junit.Assert.*;
 
 /**
- * Test cases for {@link WindowLeapArray}.
+ * Test cases for {@link MetricsLeapArray}.
  *
  * @author Eric Zhao
  */
-public class WindowLeapArrayTest {
+public class MetricsLeapArrayTest {
 
     private final int windowLengthInMs = 1000;
     private final int intervalInSec = 2;
 
     @Test
     public void testNewWindow() {
-        WindowLeapArray leapArray = new WindowLeapArray(windowLengthInMs, intervalInSec);
+        MetricsLeapArray leapArray = new MetricsLeapArray(windowLengthInMs, intervalInSec);
         long time = TimeUtil.currentTimeMillis();
-        WindowWrap<Window> window = leapArray.currentWindow(time);
+        WindowWrap<MetricBucket> window = leapArray.currentWindow(time);
 
         assertEquals(window.windowLength(), windowLengthInMs);
         assertEquals(window.windowStart(), time - time % windowLengthInMs);
@@ -54,11 +54,11 @@ public class WindowLeapArrayTest {
 
     @Test
     public void testLeapArrayWindowStart() {
-        WindowLeapArray leapArray = new WindowLeapArray(windowLengthInMs, intervalInSec);
+        MetricsLeapArray leapArray = new MetricsLeapArray(windowLengthInMs, intervalInSec);
         long firstTime = TimeUtil.currentTimeMillis();
         long previousWindowStart = firstTime - firstTime % windowLengthInMs;
 
-        WindowWrap<Window> window = leapArray.currentWindow(firstTime);
+        WindowWrap<MetricBucket> window = leapArray.currentWindow(firstTime);
 
         assertEquals(windowLengthInMs, window.windowLength());
         assertEquals(previousWindowStart, window.windowStart());
@@ -66,15 +66,15 @@ public class WindowLeapArrayTest {
 
     @Test
     public void testWindowAfterOneInterval() {
-        WindowLeapArray leapArray = new WindowLeapArray(windowLengthInMs, intervalInSec);
+        MetricsLeapArray leapArray = new MetricsLeapArray(windowLengthInMs, intervalInSec);
         long firstTime = TimeUtil.currentTimeMillis();
         long previousWindowStart = firstTime - firstTime % windowLengthInMs;
-        WindowWrap<Window> window = leapArray.currentWindow(previousWindowStart);
+        WindowWrap<MetricBucket> window = leapArray.currentWindow(previousWindowStart);
 
         assertEquals(windowLengthInMs, window.windowLength());
         assertEquals(previousWindowStart, window.windowStart());
 
-        Window currentWindow = window.value();
+        MetricBucket currentWindow = window.value();
         assertNotNull(currentWindow);
 
         currentWindow.addPass();
@@ -87,7 +87,7 @@ public class WindowLeapArrayTest {
         window = leapArray.currentWindow(middleTime);
         assertEquals(previousWindowStart, window.windowStart());
 
-        Window middleWindow = window.value();
+        MetricBucket middleWindow = window.value();
         middleWindow.addPass();
         assertSame(currentWindow, middleWindow);
         assertEquals(2L, middleWindow.pass());
@@ -106,18 +106,18 @@ public class WindowLeapArrayTest {
 
     @Deprecated
     public void testWindowDeprecatedRefresh() {
-        WindowLeapArray leapArray = new WindowLeapArray(windowLengthInMs, intervalInSec);
+        MetricsLeapArray leapArray = new MetricsLeapArray(windowLengthInMs, intervalInSec);
         final int len = intervalInSec * 1000 / windowLengthInMs;
         long firstTime = TimeUtil.currentTimeMillis();
-        List<WindowWrap<Window>> firstIterWindowList = new ArrayList<WindowWrap<Window>>(len);
+        List<WindowWrap<MetricBucket>> firstIterWindowList = new ArrayList<WindowWrap<MetricBucket>>(len);
         for (int i = 0; i < len; i++) {
-            WindowWrap<Window> w = leapArray.currentWindow(firstTime + windowLengthInMs * i);
+            WindowWrap<MetricBucket> w = leapArray.currentWindow(firstTime + windowLengthInMs * i);
             w.value().addPass();
             firstIterWindowList.add(i, w);
         }
 
         for (int i = len; i < len * 2; i++) {
-            WindowWrap<Window> w = leapArray.currentWindow(firstTime + windowLengthInMs * i);
+            WindowWrap<MetricBucket> w = leapArray.currentWindow(firstTime + windowLengthInMs * i);
             assertNotSame(w, firstIterWindowList.get(i - len));
         }
     }
@@ -126,7 +126,7 @@ public class WindowLeapArrayTest {
     public void testMultiThreadUpdateEmptyWindow() throws Exception {
         final long time = TimeUtil.currentTimeMillis();
         final int nThreads = 16;
-        final WindowLeapArray leapArray = new WindowLeapArray(windowLengthInMs, intervalInSec);
+        final MetricsLeapArray leapArray = new MetricsLeapArray(windowLengthInMs, intervalInSec);
         final CountDownLatch latch = new CountDownLatch(nThreads);
         Runnable task = new Runnable() {
             @Override
@@ -147,9 +147,9 @@ public class WindowLeapArrayTest {
 
     @Test
     public void testGetPreviousWindow() {
-        WindowLeapArray leapArray = new WindowLeapArray(windowLengthInMs, intervalInSec);
+        MetricsLeapArray leapArray = new MetricsLeapArray(windowLengthInMs, intervalInSec);
         long time = TimeUtil.currentTimeMillis();
-        WindowWrap<Window> previousWindow = leapArray.currentWindow(time);
+        WindowWrap<MetricBucket> previousWindow = leapArray.currentWindow(time);
         assertNull(leapArray.getPreviousWindow(time));
 
         long nextTime = time + windowLengthInMs;
@@ -165,16 +165,16 @@ public class WindowLeapArrayTest {
         final int intervalInSec = 1;
         final int intervalInMs = intervalInSec * 1000;
 
-        WindowLeapArray leapArray = new WindowLeapArray(windowLengthInMs, intervalInSec);
+        MetricsLeapArray leapArray = new MetricsLeapArray(windowLengthInMs, intervalInSec);
         long time = TimeUtil.currentTimeMillis();
 
-        Set<WindowWrap<Window>> windowWraps = new HashSet<WindowWrap<Window>>();
+        Set<WindowWrap<MetricBucket>> windowWraps = new HashSet<WindowWrap<MetricBucket>>();
 
         windowWraps.add(leapArray.currentWindow(time));
         windowWraps.add(leapArray.currentWindow(time + windowLengthInMs));
 
-        List<WindowWrap<Window>> list = leapArray.list();
-        for (WindowWrap<Window> wrap : list) {
+        List<WindowWrap<MetricBucket>> list = leapArray.list();
+        for (WindowWrap<MetricBucket> wrap : list) {
             assertTrue(windowWraps.contains(wrap));
         }
 
@@ -191,18 +191,18 @@ public class WindowLeapArrayTest {
         final int windowLengthInMs = 100;
         final int intervalInSec = 1;
 
-        WindowLeapArray leapArray = new WindowLeapArray(windowLengthInMs, intervalInSec);
+        MetricsLeapArray leapArray = new MetricsLeapArray(windowLengthInMs, intervalInSec);
         long time = TimeUtil.currentTimeMillis();
 
-        Set<WindowWrap<Window>> windowWraps = new HashSet<WindowWrap<Window>>();
+        Set<WindowWrap<MetricBucket>> windowWraps = new HashSet<WindowWrap<MetricBucket>>();
 
         windowWraps.add(leapArray.currentWindow(time));
         windowWraps.add(leapArray.currentWindow(time + windowLengthInMs));
 
         Thread.sleep(intervalInSec * 1000 + windowLengthInMs * 3);
 
-        List<WindowWrap<Window>> list = leapArray.list();
-        for (WindowWrap<Window> wrap : list) {
+        List<WindowWrap<MetricBucket>> list = leapArray.list();
+        for (WindowWrap<MetricBucket> wrap : list) {
             assertTrue(windowWraps.contains(wrap));
         }
 
diff --git a/sentinel-core/src/test/java/com/alibaba/csp/sentinel/slots/block/flow/WarmUpFlowTest.java b/sentinel-core/src/test/java/com/alibaba/csp/sentinel/slots/block/flow/WarmUpFlowTest.java
index 6cda853d..953b66cf 100755
--- a/sentinel-core/src/test/java/com/alibaba/csp/sentinel/slots/block/flow/WarmUpFlowTest.java
+++ b/sentinel-core/src/test/java/com/alibaba/csp/sentinel/slots/block/flow/WarmUpFlowTest.java
@@ -39,12 +39,6 @@ public class WarmUpFlowTest {
 
         FlowRuleManager.loadRules(Arrays.asList(flowRule));
 
-        //ContextUtil.enter(null);
-
-        //when(flowRule.selectNodeByRequsterAndStrategy(null, null, null)).thenReturn(value)
-
-        // flowRule.passCheck(null, DefaultNode, acquireCount, args)
-        // when(leapArray.values()).thenReturn(new ArrayList<Window>() {{ add(windowWrap.value()); }});
         ContextUtil.enter("test");
 
         ContextUtil.exit();