diff --git a/container/gring/gring.go b/container/gring/gring.go
index 08fddc982..08c4e51ab 100644
--- a/container/gring/gring.go
+++ b/container/gring/gring.go
@@ -193,17 +193,17 @@ func (r *Ring) RLockIteratorNext(f func(value interface{}) bool) {
 	}
 }
 
-// LockIteratorPrev iterates and locks writing backward
+// RLockIteratorPrev iterates and locks writing backward
 // with given callback function `f` within RWMutex.RLock.
 // If `f` returns true, then it continues iterating; or false to stop.
-func (r *Ring) LockIteratorPrev(f func(item *ring.Ring) bool) {
+func (r *Ring) RLockIteratorPrev(f func(value interface{}) bool) {
 	r.mu.RLock()
 	defer r.mu.RUnlock()
-	if !f(r.ring) {
+	if r.ring.Value != nil && !f(r.ring.Value.(internalRingItem).Value) {
 		return
 	}
 	for p := r.ring.Prev(); p != r.ring; p = p.Prev() {
-		if !f(p) {
+		if p.Value == nil || !f(p.Value.(internalRingItem).Value) {
 			break
 		}
 	}
diff --git a/container/gring/gring_z_example_test.go b/container/gring/gring_z_example_test.go
new file mode 100644
index 000000000..6b7032f9e
--- /dev/null
+++ b/container/gring/gring_z_example_test.go
@@ -0,0 +1,289 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
+package gring_test
+
+import (
+	"fmt"
+	"github.com/gogf/gf/v2/container/gring"
+)
+
+func ExampleNew() {
+	// Non concurrent safety
+	gring.New(10)
+
+	// Concurrent safety
+	gring.New(10, true)
+
+	// Output:
+}
+
+func ExampleRing_Val() {
+	r := gring.New(10)
+	r.Set(1)
+	fmt.Println("Val:", r.Val())
+
+	r.Next().Set("GoFrame")
+	fmt.Println("Val:", r.Val())
+
+	// Output:
+	// Val: 1
+	// Val: GoFrame
+}
+
+func ExampleRing_Len() {
+	r1 := gring.New(10)
+	for i := 0; i < 5; i++ {
+		r1.Set(i).Next()
+	}
+	fmt.Println("Len:", r1.Len())
+
+	r2 := gring.New(10, true)
+	for i := 0; i < 10; i++ {
+		r2.Set(i).Next()
+	}
+	fmt.Println("Len:", r2.Len())
+
+	// Output:
+	// Len: 5
+	// Len: 10
+}
+
+func ExampleRing_Cap() {
+	r1 := gring.New(10)
+	for i := 0; i < 5; i++ {
+		r1.Set(i).Next()
+	}
+	fmt.Println("Cap:", r1.Cap())
+
+	r2 := gring.New(10, true)
+	for i := 0; i < 10; i++ {
+		r2.Set(i).Next()
+	}
+	fmt.Println("Cap:", r2.Cap())
+
+	// Output:
+	// Cap: 10
+	// Cap: 10
+}
+
+func ExampleRing_Set() {
+	r := gring.New(10)
+	r.Set(1)
+	fmt.Println("Val:", r.Val())
+
+	r.Next().Set("GoFrame")
+	fmt.Println("Val:", r.Val())
+
+	// Output:
+	// Val: 1
+	// Val: GoFrame
+}
+
+func ExampleRing_Put() {
+	r := gring.New(10)
+	r.Put(1)
+	fmt.Println("Val:", r.Val())
+	fmt.Println("Val:", r.Prev().Val())
+
+	// Output:
+	// Val: <nil>
+	// Val: 1
+}
+
+func ExampleRing_Move() {
+	r := gring.New(10)
+	for i := 0; i < 10; i++ {
+		r.Set(i).Next()
+	}
+	// ring at Pos 0
+	fmt.Println("CurVal:", r.Val())
+
+	r.Move(5)
+
+	// ring at Pos 5
+	fmt.Println("CurVal:", r.Val())
+
+	// Output:
+	// CurVal: 0
+	// CurVal: 5
+}
+
+func ExampleRing_Prev() {
+	r := gring.New(10)
+	for i := 0; i < 5; i++ {
+		r.Set(i).Next()
+	}
+
+	fmt.Println("Prev:", r.Prev().Val())
+	fmt.Println("Prev:", r.Prev().Val())
+
+	// Output:
+	// Prev: 4
+	// Prev: 3
+}
+
+func ExampleRing_Next() {
+	r := gring.New(10)
+	for i := 5; i > 0; i-- {
+		r.Set(i).Prev()
+	}
+
+	fmt.Println("Prev:", r.Next().Val())
+	fmt.Println("Prev:", r.Next().Val())
+
+	// Output:
+	// Prev: 1
+	// Prev: 2
+}
+
+func ExampleRing_Link_Common() {
+	r := gring.New(10)
+	for i := 0; i < 5; i++ {
+		r.Set(i).Next()
+	}
+
+	s := gring.New(10)
+	for i := 0; i < 10; i++ {
+		val := i + 5
+		s.Set(val).Next()
+	}
+
+	r.Link(s) // Link Ring s to Ring r
+
+	fmt.Println("Len:", r.Len())
+	fmt.Println("Cap:", r.Cap())
+	fmt.Println(r.SlicePrev())
+	fmt.Println(r.SliceNext())
+
+	// Output:
+	// Len: 15
+	// Cap: 20
+	// [4 3 2 1 0]
+	// [5 6 7 8 9 10 11 12 13 14]
+}
+
+func ExampleRing_Link_SameRing() {
+	r := gring.New(10)
+	for i := 0; i < 5; i++ {
+		r.Set(i).Next()
+	}
+
+	same_r := r.Link(r.Prev())
+
+	fmt.Println("Len:", same_r.Len())
+	fmt.Println("Cap:", same_r.Cap())
+	fmt.Println(same_r.SlicePrev())
+	fmt.Println(same_r.SliceNext())
+
+	// Output:
+	// Len: 1
+	// Cap: 1
+	// [4]
+	// [4]
+}
+
+func ExampleRing_Unlink() {
+	r := gring.New(10)
+	for i := 0; i < 10; i++ {
+		r.Set(i).Next()
+	}
+
+	fmt.Println("Before Unlink, Len:", r.Len())
+	fmt.Println("Before Unlink, Cap:", r.Cap())
+	fmt.Println("Before Unlink, ", r.SlicePrev())
+	fmt.Println("Before Unlink, ", r.SliceNext())
+
+	r.Unlink(7)
+
+	fmt.Println("After Unlink, Len:", r.Len())
+	fmt.Println("After Unlink, Cap:", r.Cap())
+	fmt.Println("After Unlink, ", r.SlicePrev())
+	fmt.Println("After Unlink, ", r.SliceNext())
+
+	// Output:
+	// Before Unlink, Len: 10
+	// Before Unlink, Cap: 10
+	// Before Unlink,  [0 9 8 7 6 5 4 3 2 1]
+	// Before Unlink,  [0 1 2 3 4 5 6 7 8 9]
+	// After Unlink, Len: 7
+	// After Unlink, Cap: 7
+	// After Unlink,  [1 7 6 5 4 3 2]
+	// After Unlink,  [1 2 3 4 5 6 7]
+}
+
+func ExampleRing_RLockIteratorNext() {
+	r := gring.New(10)
+	for i := 0; i < 10; i++ {
+		r.Set(i).Next()
+	}
+
+	r.RLockIteratorNext(func(value interface{}) bool {
+		if value.(int) < 5 {
+			fmt.Println("IteratorNext Success, Value:", value)
+			return true
+		}
+
+		return false
+	})
+
+	// Output:
+	// IteratorNext Success, Value: 0
+	// IteratorNext Success, Value: 1
+	// IteratorNext Success, Value: 2
+	// IteratorNext Success, Value: 3
+	// IteratorNext Success, Value: 4
+}
+
+func ExampleRing_RLockIteratorPrev() {
+	r := gring.New(10)
+	for i := 0; i < 10; i++ {
+		r.Set(i).Next()
+	}
+
+	// move r to pos 9
+	r.Prev()
+
+	r.RLockIteratorPrev(func(value interface{}) bool {
+		if value.(int) >= 5 {
+			fmt.Println("IteratorPrev Success, Value:", value)
+			return true
+		}
+
+		return false
+	})
+
+	// Output:
+	// IteratorPrev Success, Value: 9
+	// IteratorPrev Success, Value: 8
+	// IteratorPrev Success, Value: 7
+	// IteratorPrev Success, Value: 6
+	// IteratorPrev Success, Value: 5
+}
+
+func ExampleRing_SliceNext() {
+	r := gring.New(10)
+	for i := 0; i < 10; i++ {
+		r.Set(i).Next()
+	}
+
+	fmt.Println(r.SliceNext())
+
+	// Output:
+	// [0 1 2 3 4 5 6 7 8 9]
+}
+
+func ExampleRing_SlicePrev() {
+	r := gring.New(10)
+	for i := 0; i < 10; i++ {
+		r.Set(i).Next()
+	}
+
+	fmt.Println(r.SlicePrev())
+
+	// Output:
+	// [0 9 8 7 6 5 4 3 2 1]
+}