diff --git a/src/StrictArray.php b/src/StrictArray.php
new file mode 100644
index 0000000..195fb98
--- /dev/null
+++ b/src/StrictArray.php
@@ -0,0 +1,87 @@
+<?php
+
+
+namespace EasySwoole\Spl;
+
+
+class StrictArray implements \ArrayAccess ,\Countable ,\Iterator
+{
+    private $class;
+    private $data = [];
+    private $currentKey;
+    private $keys = [];
+
+    function __construct(string $itemClass)
+    {
+        $this->class = $itemClass;
+    }
+
+    public function offsetExists($offset)
+    {
+        return isset($this->data[$offset]);
+    }
+
+    public function offsetGet($offset)
+    {
+        if(isset($this->data[$offset])){
+            return $this->data[$offset];
+        }else{
+            return null;
+        }
+    }
+
+    public function offsetSet($offset, $value)
+    {
+        if(is_a($value,$this->class)){
+            $this->data[$offset] = $value;
+            return true;
+        }
+        throw new \Exception("StrictArray can only set {$this->class} object");
+    }
+
+    public function offsetUnset($offset)
+    {
+        if(isset($this->data[$offset])){
+            unset($this->data[$offset]);
+            return true;
+        }else{
+            return false;
+        }
+    }
+
+    public function count()
+    {
+        return count($this->data);
+    }
+
+    public function current()
+    {
+        return $this->data[$this->currentKey];
+    }
+
+    public function next()
+    {
+        $this->currentKey = array_shift($this->keys);
+    }
+
+    public function key()
+    {
+        if($this->currentKey === null){
+            $this->rewind();
+        }
+        return $this->currentKey;
+    }
+
+    public function valid()
+    {
+        return isset($this->data[$this->currentKey]);
+    }
+
+    public function rewind()
+    {
+        $this->currentKey = null;
+        $this->keys = [];
+        $this->keys = array_keys($this->data);
+        $this->currentKey = array_shift($this->keys);
+    }
+}
\ No newline at end of file