base.php

См. документацию.

<?php
namespace Bitrix\Iblock\Template\Entity;

class Base
{
    protected $id = null;
    protected $fields = null;
    protected $fieldMap = array();

    protected static $instance = [];
    protected static function getInstance($id)
    {
        $class = get_called_class();
        if (!isset(static::$instance[$class]))
        {
            static::$instance[$class] = [];
        }
        if (!isset(static::$instance[$class][$id]))
        {
            static::$instance[$class][$id] = new static($id);
        }
        return static::$instance[$class][$id];
    }
 

    public function __construct($id)
    {
        $this->id = $id;
    }

    public function getId()
    {
        return $this->id;
    }

    public function resolve($entity)
    {
        if ($entity === "this")
            return $this;
        else
            return new Base(0);
    }

    public function setFields(array $fields)
    {
        $this->fields = $fields;
    }

    public function getField($fieldName)
    {
        if (!$this->loadFromDatabase())
            return "";
 
        if (!isset($this->fieldMap[$fieldName]))
            return "";
 
        $fieldName = $this->fieldMap[$fieldName];
        if (!isset($this->fields[$fieldName]))
            return "";
 
        $fieldValue = $this->fields[$fieldName];
        if (is_array($fieldValue))
        {
            $result = array();
            foreach($fieldValue as $key => $value)
            {
                if ($value instanceof LazyValueLoader)
                    $result[$key] = $value->getValue();
                else
                    $result[$key] = $value;
 
            }
            return $result;
        }
        else
        {
            if ($fieldValue instanceof LazyValueLoader)
            {
                return $fieldValue->getValue();
            }
            return $this->fields[$fieldName];
        }
    }

    protected function loadFromDatabase()
    {
        if (!isset($this->fields))
        {
            $this->fields = array();
        }
        return true;
    }

    protected function addField($fieldName, $internalName, $value)
    {
        if (!isset($this->fields[$internalName]))
            $this->fields[$internalName] = $value;
        $this->fieldMap[mb_strtolower($fieldName)] = $internalName;
    }
}

class LazyValueLoader
{
    protected $value = null;
    protected $key = null;

    function __construct($key)
    {
        $this->key = $key;
    }

    public function __toString()
    {
        if (!isset($this->value))
            $this->value = $this->load();
        return $this->value;
    }

    public function getValue()
    {
        if (!isset($this->value))
            $this->value = $this->load();
        return $this->value;
    }

    protected function load()
    {
        return "";
    }
}