Refactored duplicated code that was used for extracting properties from

an array into a trait

Cake/Collection/CollectionTrait.php

@@ -27,6 +27,8 @@
  */
 trait CollectionTrait {
 
+	use ExtractTrait;
+
 /**
  * Executes the passed callable for each of the elements in this collection
  * and passes both the value and key for them on each step.
@@ -624,44 +626,4 @@ public function jsonSerialize() {
 		return $this->toArray();
 	}
 
-/**
- * Returns a callable that can be used to extract a property or column from
- * an array or object based on a dot separated path.
- *
- * @param string|callable $callback A dot separated path of column to follow
- * so that the final one can be returned or a callable that will take care
- * of doing that.
- * @return callable
- */
-	protected function _propertyExtractor($callback) {
-		if (is_string($callback)) {
-			$path = $path = explode('.', $callback);
-			$callback = function($element) use ($path) {
-				return $this->_extract($element, $path);
-			};
-		}
-
-		return $callback;
-	}
-
-/**
- * Returns a column from $data that can be extracted
- * by iterating over the column names contained in $path
- *
- * @param array|\ArrayAccess $data
- * @param array $path
- * @return mixed
- */
-	protected function _extract($data, $path) {
-		$value = null;
-		foreach ($path as $column) {
-			if (!isset($data[$column])) {
-				return null;
-			}
-			$value = $data[$column];
-			$data = $value;
-		}
-		return $value;
-	}
-
 }

Cake/Collection/Iterator/SortIterator.php

@@ -14,6 +14,7 @@
  */
 namespace Cake\Collection\Iterator;
 
+use Cake\Collection\ExtractTrait;
 use SplHeap;
 
 /**
@@ -38,6 +39,8 @@
  */
 class SortIterator extends SplHeap {
 
+	use ExtractTrait;
+
 /**
  * Original items passed to this iterator
  *
@@ -89,23 +92,7 @@ public function __construct($items, $c, $dir = SORT_DESC, $type = SORT_NUMERIC)
 		$this->_items = $items;
 		$this->_dir = $dir;
 		$this->_type = $type;
-
-		if (is_string($c)) {
-			$path = explode('.', $c);
-			$c = function($current) use ($path) {
-				$value = null;
-				foreach ($path as $column) {
-					if (!isset($current[$column])) {
-						return null;
-					}
-					$value = $current[$column];
-					$current = $value;
-				}
-				return $value;
-			};
-		}
-
-		$this->_callback = $c;
+		$this->_callback = $this->_propertyExtractor($c);
 	}
 
 /**