From 1b42a4241a7996be43196f97e814b6755a8cdbae Mon Sep 17 00:00:00 2001
From: Redkale <22250530@qq.com>
Date: Thu, 21 Jul 2016 15:39:32 +0800
Subject: [PATCH]

---
 src/org/redkale/source/Flipper.java | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/org/redkale/source/Flipper.java b/src/org/redkale/source/Flipper.java
index f3ca828bb..494e01606 100644
--- a/src/org/redkale/source/Flipper.java
+++ b/src/org/redkale/source/Flipper.java
@@ -98,6 +98,11 @@ public final class Flipper implements Serializable, Cloneable {
         return sort;
     }
 
+    public static Flipper sortIfAbsent(Flipper flipper, String sort) {
+        if (flipper != null) return flipper.sortIfAbsent(sort);
+        return flipper;
+    }
+
     public Flipper sortIfAbsent(String sort) {
         if (this.sort == null || this.sort.isEmpty()) {
             this.sort = sort;