use LongAdder instead of AtomicLong

leaf-core/src/main/java/com/sankuai/inf/leaf/segment/SegmentIDGenImpl.java

@@ -12,7 +12,7 @@
 
 import java.util.*;
 import java.util.concurrent.*;
-import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.atomic.LongAdder;
 
 public class SegmentIDGenImpl implements IDGen {
     private static final Logger logger = LoggerFactory.getLogger(SegmentIDGenImpl.class);
@@ -106,7 +106,7 @@ private void updateCacheFromDb() {
                 SegmentBuffer buffer = new SegmentBuffer();
                 buffer.setKey(tag);
                 Segment segment = buffer.getCurrent();
-                segment.setValue(new AtomicLong(0));
+                segment.setValue(new LongAdder());
                 segment.setMax(0);
                 segment.setStep(0);
                 cache.put(tag, buffer);
@@ -193,7 +193,7 @@ public void updateSegmentFromDb(String key, Segment segment) {
         }
         // must set value before set max
         long value = leafAlloc.getMaxId() - buffer.getStep();
-        segment.getValue().set(value);
+        segment.reset(value);
         segment.setMax(leafAlloc.getMaxId());
         segment.setStep(buffer.getStep());
         sw.stop("updateSegmentFromDb", key + " " + segment);
@@ -229,7 +229,7 @@ public void run() {
                         }
                     });
                 }
-                long value = segment.getValue().getAndIncrement();
+                long value = segment.getAndIncrement();
                 if (value < segment.getMax()) {
                     return new Result(value, Status.SUCCESS);
                 }
@@ -240,7 +240,7 @@ public void run() {
             buffer.wLock().lock();
             try {
                 final Segment segment = buffer.getCurrent();
-                long value = segment.getValue().getAndIncrement();
+                long value = segment.getAndIncrement();
                 if (value < segment.getMax()) {
                     return new Result(value, Status.SUCCESS);
                 }

leaf-core/src/main/java/com/sankuai/inf/leaf/segment/model/Segment.java

@@ -1,9 +1,9 @@
 package com.sankuai.inf.leaf.segment.model;
 
-import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.atomic.LongAdder;
 
 public class Segment {
-    private AtomicLong value = new AtomicLong(0);
+    private LongAdder value = new LongAdder();
     private volatile long max;
     private volatile int step;
     private SegmentBuffer buffer;
@@ -12,11 +12,11 @@ public Segment(SegmentBuffer buffer) {
         this.buffer = buffer;
     }
 
-    public AtomicLong getValue() {
+    public LongAdder getValue() {
         return value;
     }
 
-    public void setValue(AtomicLong value) {
+    public void setValue(LongAdder value) {
         this.value = value;
     }
 
@@ -41,7 +41,7 @@ public SegmentBuffer getBuffer() {
     }
 
     public long getIdle() {
-        return this.getMax() - getValue().get();
+        return this.getMax() - getValue().sum();
     }
 
     @Override
@@ -56,4 +56,16 @@ public String toString() {
         sb.append(")");
         return sb.toString();
     }
+
+    // get then increment
+    public long getAndIncrement(){
+        long ret = value.sum();
+        value.increment();
+        return ret;
+    }
+
+    public void reset(long value) {
+        this.value.reset();
+        this.value.add(value);
+    }
 }

leaf-server/src/main/java/com/sankuai/inf/leaf/server/controller/LeafMonitorController.java

@@ -44,11 +44,11 @@ public String getCache(Model model) {
             sv.setPos(buffer.getCurrentPos());
             sv.setNextReady(buffer.isNextReady());
             sv.setMax0(buffer.getSegments()[0].getMax());
-            sv.setValue0(buffer.getSegments()[0].getValue().get());
+            sv.setValue0(buffer.getSegments()[0].getValue().sum());
             sv.setStep0(buffer.getSegments()[0].getStep());
 
             sv.setMax1(buffer.getSegments()[1].getMax());
-            sv.setValue1(buffer.getSegments()[1].getValue().get());
+            sv.setValue1(buffer.getSegments()[1].getValue().sum());
             sv.setStep1(buffer.getSegments()[1].getStep());
 
             data.put(entry.getKey(), sv);