Introduce InstancePoolTrait

src/Propel/Runtime/ActiveQuery/InstancePoolTrait.php

@@ -0,0 +1,62 @@
+<?php
+
+/**
+ * This file is part of the Propel package.
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @license MIT License
+ */
+
+namespace Propel\Runtime\ActiveQuery;
+
+use Propel\Runtime\Propel;
+use Propel\Runtime\Exception\RuntimeException;
+
+trait InstancePoolTrait
+{
+    private static $instances = array();
+
+    public static function addInstanceToPool($object, $key = null)
+    {
+        if (Propel::isInstancePoolingEnabled()) {
+            if (null === $key) {
+                $key = (string) $object->getId();
+            }
+
+            self::$instances[$key] = $object;
+        }
+    }
+
+    public static function removeInstanceFromPool($value)
+    {
+        if (Propel::isInstancePoolingEnabled() && null !== $value) {
+            if (is_object($value)) {
+                $key = (string) $value->getId();
+            } elseif (is_scalar($value)) {
+                // assume we've been passed a primary key
+                $key = (string) $value;
+            } else {
+                throw new RuntimeException('Invalid value passed to removeInstanceFromPool()');
+            }
+
+            unset(self::$instances[$key]);
+        }
+    }
+
+    public static function getInstanceFromPool($key)
+    {
+        if (Propel::isInstancePoolingEnabled()) {
+            if (isset(self::$instances[$key])) {
+                return self::$instances[$key];
+            }
+        }
+
+        return null;
+    }
+
+    public static function clearInstancePool()
+    {
+        self::$instances = array();
+    }
+}