diff --git a/cosid-core/src/main/java/me/ahoo/cosid/snowflake/AbstractSnowflakeId.java b/cosid-core/src/main/java/me/ahoo/cosid/snowflake/AbstractSnowflakeId.java
index 4879d95f2c..74d76ae8bf 100644
--- a/cosid-core/src/main/java/me/ahoo/cosid/snowflake/AbstractSnowflakeId.java
+++ b/cosid-core/src/main/java/me/ahoo/cosid/snowflake/AbstractSnowflakeId.java
@@ -24,16 +24,16 @@
  * @author ahoo wang
  */
 public abstract class AbstractSnowflakeId implements SnowflakeId {
-    
+
     protected final long epoch;
     protected final int timestampBit;
     protected final int machineBit;
     protected final int sequenceBit;
-    
+
     protected final long maxTimestamp;
     protected final long maxSequence;
-    protected final int maxMachine;
-    
+    protected final int maxMachineId;
+
     protected final long machineLeft;
     protected final long timestampLeft;
     /**
@@ -43,7 +43,7 @@ public abstract class AbstractSnowflakeId implements SnowflakeId {
     private final long sequenceResetThreshold;
     protected long sequence = 0L;
     protected long lastTimestamp = -1L;
-    
+
     public AbstractSnowflakeId(long epoch,
                                int timestampBit,
                                int machineBit,
@@ -59,16 +59,16 @@ public AbstractSnowflakeId(long epoch,
         this.sequenceBit = sequenceBit;
         this.maxTimestamp = ~(-1L << timestampBit);
         this.maxSequence = ~(-1L << sequenceBit);
-        this.maxMachine = ~(-1 << machineBit);
+        this.maxMachineId = ~(-1 << machineBit);
         this.machineLeft = sequenceBit;
         this.timestampLeft = this.machineLeft + machineBit;
-        if (machineId > this.maxMachine || machineId < 0) {
-            throw new IllegalArgumentException(Strings.lenientFormat("machineId can't be greater than maxMachine[%s] or less than 0 .", maxMachine));
+        if (machineId > this.maxMachineId || machineId < 0) {
+            throw new IllegalArgumentException(Strings.lenientFormat("machineId[%s] can't be greater than maxMachineId[%s] or less than 0 .", machineId, maxMachineId));
         }
         this.machineId = machineId;
         this.sequenceResetThreshold = sequenceResetThreshold;
     }
-    
+
     protected long nextTime() {
         long time = getCurrentTime();
         while (time <= lastTimestamp) {
@@ -76,34 +76,34 @@ protected long nextTime() {
         }
         return time;
     }
-    
+
     /**
      * get current timestamp.
      *
      * @return current timestamp
      */
     protected abstract long getCurrentTime();
-    
+
     @Override
     public synchronized long generate() {
         long currentTimestamp = getCurrentTime();
         if (currentTimestamp < lastTimestamp) {
             throw new ClockBackwardsException(lastTimestamp, currentTimestamp);
         }
-        
+
         //region Reset sequence based on sequence reset threshold,Optimize the problem of uneven sharding.
-        
+
         if (currentTimestamp > lastTimestamp
-            && sequence >= sequenceResetThreshold) {
+                && sequence >= sequenceResetThreshold) {
             sequence = 0L;
         }
-        
+
         sequence = (sequence + 1) & maxSequence;
-        
+
         if (sequence == 0L) {
             currentTimestamp = nextTime();
         }
-        
+
         //endregion
         lastTimestamp = currentTimestamp;
         long diffTimestamp = (currentTimestamp - epoch);
@@ -111,53 +111,53 @@ public synchronized long generate() {
             throw new TimestampOverflowException(epoch, diffTimestamp, maxTimestamp);
         }
         return diffTimestamp << timestampLeft
-            | machineId << machineLeft
-            | sequence;
+                | machineId << machineLeft
+                | sequence;
     }
-    
+
     @Override
     public long getEpoch() {
         return epoch;
     }
-    
+
     @Override
     public int getTimestampBit() {
         return timestampBit;
     }
-    
+
     @Override
     public int getMachineBit() {
         return machineBit;
     }
-    
+
     @Override
     public int getSequenceBit() {
         return sequenceBit;
     }
-    
+
     @Override
     public long getMaxTimestamp() {
         return maxTimestamp;
     }
-    
+
     @Override
-    public int getMaxMachine() {
-        return maxMachine;
+    public int getMaxMachineId() {
+        return maxMachineId;
     }
-    
+
     @Override
     public long getMaxSequence() {
         return maxSequence;
     }
-    
+
     @Override
     public long getLastTimestamp() {
         return lastTimestamp;
     }
-    
+
     @Override
     public int getMachineId() {
         return (int) machineId;
     }
-    
+
 }
diff --git a/cosid-core/src/main/java/me/ahoo/cosid/snowflake/ClockSyncSnowflakeId.java b/cosid-core/src/main/java/me/ahoo/cosid/snowflake/ClockSyncSnowflakeId.java
index b028615bf7..497275f896 100644
--- a/cosid-core/src/main/java/me/ahoo/cosid/snowflake/ClockSyncSnowflakeId.java
+++ b/cosid-core/src/main/java/me/ahoo/cosid/snowflake/ClockSyncSnowflakeId.java
@@ -97,8 +97,8 @@ public long getMaxTimestamp() {
     }
 
     @Override
-    public int getMaxMachine() {
-        return actual.getMaxMachine();
+    public int getMaxMachineId() {
+        return actual.getMaxMachineId();
     }
 
     @Override
diff --git a/cosid-core/src/main/java/me/ahoo/cosid/snowflake/SnowflakeId.java b/cosid-core/src/main/java/me/ahoo/cosid/snowflake/SnowflakeId.java
index fa1e482c3a..ddecd52e44 100644
--- a/cosid-core/src/main/java/me/ahoo/cosid/snowflake/SnowflakeId.java
+++ b/cosid-core/src/main/java/me/ahoo/cosid/snowflake/SnowflakeId.java
@@ -47,7 +47,7 @@ default boolean isSafeJavascript() {
 
     long getMaxTimestamp();
 
-    int getMaxMachine();
+    int getMaxMachineId();
 
     long getMaxSequence();
 
diff --git a/cosid-core/src/main/java/me/ahoo/cosid/snowflake/StringSnowflakeId.java b/cosid-core/src/main/java/me/ahoo/cosid/snowflake/StringSnowflakeId.java
index 78c276d56f..ef2fc765f1 100644
--- a/cosid-core/src/main/java/me/ahoo/cosid/snowflake/StringSnowflakeId.java
+++ b/cosid-core/src/main/java/me/ahoo/cosid/snowflake/StringSnowflakeId.java
@@ -56,8 +56,8 @@ public long getMaxTimestamp() {
     }
 
     @Override
-    public int getMaxMachine() {
-        return snowflakeId.getMaxMachine();
+    public int getMaxMachineId() {
+        return snowflakeId.getMaxMachineId();
     }
 
     @Override
diff --git a/cosid-core/src/test/java/me/ahoo/cosid/machine/ClockSyncSnowflakeIdTest.java b/cosid-core/src/test/java/me/ahoo/cosid/machine/ClockSyncSnowflakeIdTest.java
index 4113359121..b59c86cd74 100644
--- a/cosid-core/src/test/java/me/ahoo/cosid/machine/ClockSyncSnowflakeIdTest.java
+++ b/cosid-core/src/test/java/me/ahoo/cosid/machine/ClockSyncSnowflakeIdTest.java
@@ -67,8 +67,8 @@ void getMaxTimestamp() {
     }
     
     @Test
-    void getMaxMachine() {
-        assertThat(clockSyncSnowflakeId.getMaxMachine(), equalTo(1023));
+    void getMaxMachineId() {
+        assertThat(clockSyncSnowflakeId.getMaxMachineId(), equalTo(1023));
     }
     
     @Test
diff --git a/cosid-core/src/test/java/me/ahoo/cosid/snowflake/StringSnowflakeIdTest.java b/cosid-core/src/test/java/me/ahoo/cosid/snowflake/StringSnowflakeIdTest.java
index 8d68382e8d..f59c808bfa 100644
--- a/cosid-core/src/test/java/me/ahoo/cosid/snowflake/StringSnowflakeIdTest.java
+++ b/cosid-core/src/test/java/me/ahoo/cosid/snowflake/StringSnowflakeIdTest.java
@@ -47,8 +47,8 @@ void getMaxTimestamp() {
     }
     
     @Test
-    void getMaxMachine() {
-        Assertions.assertEquals(delegate.getMaxMachine(), snowflakeId.getMaxMachine());
+    void getMaxMachineId() {
+        Assertions.assertEquals(delegate.getMaxMachineId(), snowflakeId.getMaxMachineId());
     }
     
     @Test