From bb71c063e379356aee4f4cbac610488d549847f6 Mon Sep 17 00:00:00 2001
From: Not Found <577528249@qq.com>
Date: Mon, 4 May 2020 13:24:52 +0800
Subject: [PATCH] fix timestamp over

---
 .../com/sankuai/inf/leaf/snowflake/SnowflakeIDGenImpl.java | 7 +++++++
 .../snowflake/exception/OverMaxTimeStampException.java     | 7 +++++++
 2 files changed, 14 insertions(+)
 create mode 100644 leaf-core/src/main/java/com/sankuai/inf/leaf/snowflake/exception/OverMaxTimeStampException.java

diff --git a/leaf-core/src/main/java/com/sankuai/inf/leaf/snowflake/SnowflakeIDGenImpl.java b/leaf-core/src/main/java/com/sankuai/inf/leaf/snowflake/SnowflakeIDGenImpl.java
index b4f813b2..854bcba6 100644
--- a/leaf-core/src/main/java/com/sankuai/inf/leaf/snowflake/SnowflakeIDGenImpl.java
+++ b/leaf-core/src/main/java/com/sankuai/inf/leaf/snowflake/SnowflakeIDGenImpl.java
@@ -5,6 +5,7 @@
 import com.sankuai.inf.leaf.common.Result;
 import com.sankuai.inf.leaf.common.Status;
 import com.sankuai.inf.leaf.common.Utils;
+import com.sankuai.inf.leaf.snowflake.exception.OverMaxTimeStampException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -20,11 +21,13 @@ public boolean init() {
     private static final Logger LOGGER = LoggerFactory.getLogger(SnowflakeIDGenImpl.class);
 
     private final long twepoch;
+    private final long timeStampBits = 41L;
     private final long workerIdBits = 10L;
     private final long maxWorkerId = ~(-1L << workerIdBits);//最大能够分配的workerid =1023
     private final long sequenceBits = 12L;
     private final long workerIdShift = sequenceBits;
     private final long timestampLeftShift = sequenceBits + workerIdBits;
+    private final long maxTimeStamp;
     private final long sequenceMask = ~(-1L << sequenceBits);
     private long workerId;
     private long sequence = 0L;
@@ -43,6 +46,7 @@ public SnowflakeIDGenImpl(String zkAddress, int port) {
      */
     public SnowflakeIDGenImpl(String zkAddress, int port, long twepoch) {
         this.twepoch = twepoch;
+        this.maxTimeStamp = ~(-1L << timeStampBits) + twepoch;
         Preconditions.checkArgument(timeGen() > twepoch, "Snowflake not support twepoch gt currentTime");
         final String ip = Utils.getIp();
         SnowflakeZookeeperHolder holder = new SnowflakeZookeeperHolder(ip, String.valueOf(port), zkAddress);
@@ -60,6 +64,9 @@ public SnowflakeIDGenImpl(String zkAddress, int port, long twepoch) {
     @Override
     public synchronized Result get(String key) {
         long timestamp = timeGen();
+        if (timestamp>maxTimeStamp) {
+            throw new OverMaxTimeStampException("current timestamp is over maxTimeStamp, the generate id will be negative");
+        }
         if (timestamp < lastTimestamp) {
             long offset = lastTimestamp - timestamp;
             if (offset <= 5) {
diff --git a/leaf-core/src/main/java/com/sankuai/inf/leaf/snowflake/exception/OverMaxTimeStampException.java b/leaf-core/src/main/java/com/sankuai/inf/leaf/snowflake/exception/OverMaxTimeStampException.java
new file mode 100644
index 00000000..11bc2077
--- /dev/null
+++ b/leaf-core/src/main/java/com/sankuai/inf/leaf/snowflake/exception/OverMaxTimeStampException.java
@@ -0,0 +1,7 @@
+package com.sankuai.inf.leaf.snowflake.exception;
+
+public class OverMaxTimeStampException extends RuntimeException {
+    public OverMaxTimeStampException(String msg){
+        super(msg);
+    }
+}