fix

Author: zengxiangming

lib/Alcaeus/MongoDbAdapter/Helper/ReadPreference.php

@@ -41,7 +41,7 @@ public function getReadPreference()
             $this->readPreference = new \MongoDB\Driver\ReadPreference(\MongoDB\Driver\ReadPreference::PRIMARY);
         }
 
-        $mode = $this->readPreference->getMode();
+        $mode = $this->readPreference->getModeString();
 
         switch ($mode) {
             case \MongoDB\Driver\ReadPreference::PRIMARY_PREFERRED:
@@ -73,7 +73,7 @@ public function getReadPreference()
      */
     protected function getSlaveOkayFromReadPreference()
     {
-        return $this->readPreference->getMode() != \MongoDB\Driver\ReadPreference::PRIMARY;
+        return $this->readPreference->getModeString() != \MongoDB\Driver\ReadPreference::PRIMARY;
     }
 
     /**

lib/Mongo/MongoId.php

@@ -20,7 +20,7 @@
 use Alcaeus\MongoDbAdapter\TypeInterface;
 use MongoDB\BSON\ObjectID;
 
-class MongoId implements Serializable, TypeInterface, JsonSerializable
+class MongoId implements TypeInterface, JsonSerializable
 {
     /*
      * @var ObjectID