Collection of elements (class & tests)

src/Meritoo/Common/Collection/Collection.php

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+<?php
+
+/**
+ * (c) Meritoo.pl, http://www.meritoo.pl
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Meritoo\Common\Collection;
+
+use ArrayAccess;
+use ArrayIterator;
+use Countable;
+use IteratorAggregate;
+use Meritoo\Common\Utilities\Arrays;
+
+/**
+ * Collection of elements.
+ * It's a set of some elements, e.g. objects.
+ *
+ * @author    Krzysztof Niziol <krzysztof.niziol@meritoo.pl>
+ * @copyright Meritoo.pl
+ */
+class Collection implements Countable, ArrayAccess, IteratorAggregate
+{
+    /**
+     * The elements of collection
+     *
+     * @var array
+     */
+    private $elements;
+
+    /**
+     * Class constructor
+     *
+     * @param array $elements (optional) The elements of collection
+     */
+    public function __construct(array $elements = [])
+    {
+        $this->elements = $elements;
+    }
+
+    /**
+     * {@inheritdoc}
+     * Required by interface Countable
+     */
+    public function count()
+    {
+        return count($this->elements);
+    }
+
+    /**
+     * {@inheritdoc}
+     * Required by interface ArrayAccess
+     */
+    public function offsetExists($offset)
+    {
+        return $this->exists($offset);
+    }
+
+    /**
+     * {@inheritdoc}
+     * Required by interface ArrayAccess
+     */
+    public function offsetGet($offset)
+    {
+        if ($this->exists($offset)) {
+            return $this->elements[$offset];
+        }
+
+        return null;
+    }
+
+    /**
+     * {@inheritdoc}
+     * Required by interface ArrayAccess
+     */
+    public function offsetSet($offset, $value)
+    {
+        $this->elements[$offset] = $value;
+    }
+
+    /**
+     * {@inheritdoc}
+     * Required by interface ArrayAccess
+     */
+    public function offsetUnset($offset)
+    {
+        if ($this->exists($offset)) {
+            unset($this->elements[$offset]);
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     * Required by interface IteratorAggregate
+     */
+    public function getIterator()
+    {
+        return new ArrayIterator($this->elements);
+    }
+
+    /**
+     * Adds given element (at the end of collection)
+     *
+     * @param mixed $element The element to add
+     * @param mixed $index   (optional) Index / key of the element
+     * @return $this
+     */
+    public function add($element, $index = null)
+    {
+        if ($index === null) {
+            $this->elements[] = $element;
+        } else {
+            $this->elements[$index] = $element;
+        }
+
+        return $this;
+    }
+
+    /**
+     * Adds given elements (at the end of collection)
+     *
+     * @param array|Collection $elements   The elements to add
+     * @param bool|false       $useIndexes (optional) If is set to true, indexes of given elements will be used in
+     *                                     this collection. Otherwise - not.
+     * @return $this
+     */
+    public function addMultiple($elements, $useIndexes = false)
+    {
+        if (!empty($elements)) {
+            foreach ($elements as $index => $element) {
+                if (!$useIndexes) {
+                    $index = null;
+                }
+
+                $this->add($element, $index);
+            }
+        }
+
+        return $this;
+    }
+
+    /**
+     * Prepends given element (adds given element at the beginning of collection)
+     *
+     * @param mixed $element The element to prepend
+     * @return $this
+     */
+    public function prepend($element)
+    {
+        array_unshift($this->elements, $element);
+
+        return $this;
+    }
+
+    /**
+     * Removes given element
+     *
+     * @param mixed $element The element to remove
+     * @return $this
+     */
+    public function remove($element)
+    {
+        if ($this->count() > 0) {
+            foreach ($this->elements as $index => $existing) {
+                if ($element === $existing) {
+                    unset($this->elements[$index]);
+                    break;
+                }
+            }
+        }
+
+        return $this;
+    }
+
+    /**
+     * Returns information if collection is empty
+     *
+     * @return bool
+     */
+    public function isEmpty()
+    {
+        return empty($this->elements);
+    }
+
+    /**
+     * Returns information if given element is first in the collection
+     *
+     * @param mixed $element The element to verify
+     * @return bool
+     */
+    public function isFirst($element)
+    {
+        return reset($this->elements) === $element;
+    }
+
+    /**
+     * Returns information if given element is last in the collection
+     *
+     * @param mixed $element The element to verify
+     * @return bool
+     */
+    public function isLast($element)
+    {
+        return end($this->elements) === $element;
+    }
+
+    /**
+     * Returns information if the collection has given element, iow. if given element exists in the collection
+     *
+     * @param mixed $element The element to verify
+     * @return bool
+     */
+    public function has($element)
+    {
+        $index = Arrays::getIndexOf($this->elements, $element);
+
+        return $index !== null && $index !== false;
+    }
+
+    /**
+     * Returns previous element for given element
+     *
+     * @param mixed $element The element to verify
+     * @return mixed|null
+     */
+    public function getPrevious($element)
+    {
+        return Arrays::getPreviousElement($this->elements, $element);
+    }
+
+    /**
+     * Returns next element for given element
+     *
+     * @param mixed $element The element to verify
+     * @return mixed|null
+     */
+    public function getNext($element)
+    {
+        return Arrays::getNextElement($this->elements, $element);
+    }
+
+    /**
+     * Returns the first element in the collection
+     *
+     * @return mixed
+     */
+    public function getFirst()
+    {
+        return Arrays::getFirstElement($this->elements);
+    }
+
+    /**
+     * Returns the last element in the collection
+     *
+     * @return mixed
+     */
+    public function getLast()
+    {
+        return Arrays::getLastElement($this->elements);
+    }
+
+    /**
+     * Returns an array representation of the collection
+     *
+     * @return array
+     */
+    public function toArray()
+    {
+        return $this->elements;
+    }
+
+    /**
+     * Returns information if element with given index/key exists
+     *
+     * @param string|int $index The index/key of element
+     * @return bool
+     */
+    private function exists($index)
+    {
+        return isset($this->elements[$index]) || array_key_exists($index, $this->elements);
+    }
+}