Object Factory

In this document you can find proper usage of this library.

About

This library is used to easily retrieve instance of certain object without the need to provide all of its dependencies.

Requirements

• PHP: >=7.4

Overview

This library ensure to provide proper instance of object implementing certain interface, or being certain type of a class. Dependencies are required to be complex type as primitive ones (string, int, float, bool) cannot be exactly auto determined. There are two ways of defining "provider" for certain interface.

Usage

First approach is providing simple map between interface and class itself, to do so we need to call `registerInterfaceClass` method.

interface IModel {}
class Model implements IModel {}

\ObjectFactory\Factory::registerInterfaceClass(IModel::class, Model::class);

Note: Use this only when providing class has complex typed dependencies, providing class with primitive types will cause exception to be thrown.

Note: Library handle circular dependencies.

Another approach is using provider callback- function that is called when instance is requested, to achieve this we need to call `registerInterfaceInstanceProvider`. This approach is usually useful when object depends on primitive types.

interface IDatabase {}
class MySQL implements IDatabase
{
    public function __constructor(string $host, string $username, string $password, string $schema) {}
}

class PostgreSQL implements IDatabase
{
    public function __constructor(string $host, string $username, string $password, string $schema, string $role = null) {}
}

\ObjectFactory\Factory::registerInterfaceInstanceProvider(IDatabase::class, function (): IDatabase {
    switch (getenv('database.driver')) {
        case 'psql':
            return new PostgreSQL('localhost', 'admin', '', 'db', 'admin');
        case 'mysql':
        default:
            return new MySQL('localhost', 'root', '', 'database');
    }
});

There are two ways to retrieve instance of certain type. One is `getInstance` which always returns new instance of requested type.

And there is also another way by using `getSharedInstance` which always return signleton instance of requested model.

$nonShared = \ObjectFactory\Factory::getInstance(IModel::class);
$shared1 = \ObjectFactory\Factory::getSharedInstance(IModel::class);
$shared2 = \ObjectFactory\Factory::getSharedInstance(IModel::class);

var_dump($nonShared === $shared1, $shared1 === $shared2); // false, true will be the output.