Abstract implementation of the CollectionInterface.

Author: bertramakers

src/AbstractCollection.php

@@ -0,0 +1,173 @@
+<?php
+
+namespace TwoDotsTwice\Collection;
+
+use TwoDotsTwice\Collection\Exception\CollectionItemNotFoundException;
+use TwoDotsTwice\Collection\Exception\CollectionKeyNotFoundException;
+
+abstract class AbstractCollection implements CollectionInterface
+{
+    /**
+     * @var array
+     */
+    protected $items;
+
+    public function __construct()
+    {
+        $this->items = array();
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function with($item, $key = null)
+    {
+        $this->guardObjectType($item);
+
+        $copy = clone $this;
+
+        if (is_null($key)) {
+            $copy->items[] = $item;
+        } else {
+            $copy->items[$key] = $item;
+        }
+
+        return $copy;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function without($item)
+    {
+        $key = $this->getKeyFor($item);
+
+        $copy = clone $this;
+        unset($copy->items[$key]);
+        return $copy;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function withoutKey($key)
+    {
+        if (!isset($this->items[$key])) {
+            throw new CollectionKeyNotFoundException($key);
+        }
+
+        $copy = clone $this;
+        unset($copy->items[$key]);
+        return $copy;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function getByKey($key)
+    {
+        if (!isset($this->items[$key])) {
+            throw new CollectionKeyNotFoundException($key);
+        }
+
+        return $this->items[$key];
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function getKeyFor($item)
+    {
+        $this->guardObjectType($item);
+
+        $key = array_search($item, $this->items);
+
+        if ($key === false) {
+            throw new CollectionItemNotFoundException();
+        }
+
+        return $key;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function getKeys()
+    {
+        return array_keys($this->items);
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function length()
+    {
+        return count($this->items);
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function toArray()
+    {
+        return $this->items;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public static function fromArray(array $items)
+    {
+        $collection = new static();
+        foreach ($items as $item) {
+            $collection = $collection->with($item);
+        }
+        return $collection;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function getIterator()
+    {
+        return new \ArrayIterator($this->items);
+    }
+
+    /**
+     * @return string
+     */
+    abstract protected function getValidObjectType();
+
+    /**
+     * @param mixed $object
+     *   Object of which the type should be validated.
+     *
+     * @return bool
+     *   TRUE if the object is of a valid type, FALSE otherwise.
+     */
+    protected function isValidObjectType($object)
+    {
+        $type = (string) $this->getValidObjectType();
+        return ($object instanceof $type);
+    }
+
+    /**
+     * @param mixed $object
+     *   Object of which the type should be guarded.
+     *
+     * @throws \InvalidArgumentException
+     *   When the provided object is not of the specified type.
+     */
+    protected function guardObjectType($object)
+    {
+        if (!$this->isValidObjectType($object)) {
+            throw new \InvalidArgumentException(
+                sprintf(
+                    'Expected instance of %s, found %s instead.',
+                    $this->getValidObjectType(),
+                    get_class($object)
+                )
+            );
+        }
+    }
+}