[update] review-常量类

wj-datacenter-service/src/main/java/net/wanji/datacenter/common/Constants.java

 package net.wanji.datacenter.common;
 
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 
 /**
@@ -10,9 +11,12 @@ import java.util.List;
 public class Constants {
     public static final String UNDERLINE = "_";
     // 横向方向列表
-    public static final List<Integer> X_DIR_LIST = Arrays.asList(2, 3, 6, 7);
+    public static final List<Integer> X_DIR_LIST = Collections.unmodifiableList(Arrays.asList(2, 3, 6, 7));
     public static final String LANE_SNAPSHOT_DATA_ES_INDEX = "datacenter_lane_snapshot_data";
 
     public static final String CROSS_FREE_FLOW_SPEED_KEY = "crossFreeFlowSpeed";
     public static final String CROSS_FREE_FLOW_SPEED_TOPIC = "cross_free_flow_speed";
+
+    private Constants() {
+    }
 }
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