Backend Development
PHP Tutorial
PHP example detailed explanation of Constructor Prototype Pattern prototype pattern, prototypepattern_PHP tutorial
PHP example detailed explanation of Constructor Prototype Pattern prototype pattern, prototypepattern_PHP tutorial
php example detailed explanation of Constructor Prototype Pattern prototype pattern, prototypepattern
Main role in prototype pattern
Abstract prototype (Prototype) role: declare an interface that clones itself
Concrete Prototype role: implement an operation of cloning yourself
When most of a class is the same and only some parts are different, if a large number of objects of this class are needed, it will be very expensive to instantiate the same parts repeatedly every time, and if the object is created before cloning Those parts that are the same can save money.
An implementation method for PHP is to handle the initialization of this class separately with the __construct() and initialize functions. The prototype is placed in construct, which is the public part, and the special part of each object is placed in initialize. In this way, we first create a class without initializing it, and then clone this class and then initialize it every time.
This is mentioned in the zend framework official manual http://framework.zend.com/manual/2.0/en/user-guide/database-and-models.html, but it is not explained in detail. Let me analyze it below.
1. Introduction
There is an albumTable class in the zf2 model, which is equivalent to an assistant class for operating database actions, and tablegateway is used in it.
In order to initialize the albumtable with the same class every time, the initialization work is placed in getServiceConfig() of the module.php file in the root directory, which uses the factory mode, and through the callback function, when each ServiceManager ($sm ) will automatically create an alumTable when an object needs to be instantiated. We can see from the code below that creating an albumTable also requires creating an AlbumTableGateWay in the same way. This class uses the prototype pattern we are going to talk about.
2. Detailed code explanation
public function getServiceConfig()
{
return array(
'factories' => array(
'Album\Model\AlbumTable' => function($sm) {
$tableGateway = $sm->get('AlbumTableGateway');
$table = new AlbumTable($tableGateway);
return $table;
},
'AlbumTableGateway' => function ($sm) {
$dbAdapter = $sm->get('Zend\Db\Adapter\Adapter');
$resultSetPrototype = new ResultSet();
$resultSetPrototype->setArrayObjectPrototype(new Album());//这个就是一个不变的原型
return new TableGateway('album', $dbAdapter, null, $resultSetPrototype);//传入到TableGateWay的构造函数中去
},
),
);
}Note that it is not TableGateWay that uses the prototype pattern but the ResultSet class. Whenever the tablegateway calls methods such as select() or insert(), a ResultSet will be created to represent the result. The common parts of these ResultSets will be cloned, and unique partial classes such as data will be initialized.
3. More code examples
In order to understand this prototype more clearly, let’s put aside the big framework of zend and look at a complete code example. Example from
PHP Constructor Best Practices And The Prototype Pattern< /a>
The first half of this article about prototype pattern is actually a mixture of how to use inheritance in constructors to improve scalability. The two patterns may not seem easy to understand. Let’s look directly at the final code part about prototype pattern. .
<?php
//框架中很常见的adapter类，用来适配各种数据库，封装一些基本数据库连接操作。
//相当于上面代码中的adapter类
class DbAdapter {
public function fetchAllFromTable($table) {
return $arrayOfData;
}
}
//运用prototype pattern的类，注意construct和initialize是分开的
//相当于上面zend 代码里面的ResultSet类
class RowGateway {
public function __construct(DbAdapter $dbAdapter, $tableName) {
$this->dbAdapter = $dbAdapter;
$this->tableName = $tableName;
}
public function initialize($data) {
$this->data = $data;
}
/**
* Both methods require access to the database adapter
* to fulfill their duties
*/
public function save() {}
public function delete() {}
public function refresh() {}
}
//相当于上面代码中的TableGateway类，关于gateway可以具体去了解一下。
class UserRepository {
public function __construct(DbAdapter $dbAdapter, RowGateway $rowGatewayPrototype = null) {
$this->dbAdapter = $dbAdapter;
$this->rowGatewayPrototype = ($rowGatewayPrototype) ? new RowGateway($this->dbAdapter, 'user')
}
public function getUsers() {
$rows = array();
foreach ($this->dbAdapter->fetchAllFromTable('user') as $rowData) {
$rows[] = $row = clone $this->rowGatewayPrototype;
$row->initialize($rowData);
}
return $rows;
}
}These classes actually correspond to the classes in the zend code above
Dbadapter -- adpater
RowGateWay -- ResultSet
UserRepository - TableGateWay
See the comments in the code for details.
The RowGateWay here can clearly see that a large number of instantiations are required in getusers, so the prototype mode is very necessary.
The following is the code to use this class
class ReadWriteRowGateway extends RowGateway {
public function __construct(DbAdapter $readDbAdapter, DbAdapter $writeDbAdapter, $tableName) {
$this->readDbAdapter = $readDbAdapter;
parent::__construct($writeDbAdapter, $tableName);
}
public function refresh() {
// utilize $this->readDbAdapter instead of $this->dbAdapter in RowGateway base implementation
}
}
// usage:
$userRepository = new UserRepository(
$dbAdapter,
new ReadWriteRowGateway($readDbAdapter, $writeDbAdapter, 'user')
);
$users = $userRepository->getUsers();
$user = $users[0]; // instance of ReadWriteRowGateway with a specific row of data from the dbThe above content is a detailed explanation of the Constructor Prototype Pattern prototype pattern in PHP examples introduced by the editor. I hope you like it.
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
Alipay PHP SDK transfer error: How to solve the problem of 'Cannot declare class SignData'?
Apr 01, 2025 am 07:21 AM
Alipay PHP...
Explain JSON Web Tokens (JWT) and their use case in PHP APIs.
Apr 05, 2025 am 12:04 AM
JWT is an open standard based on JSON, used to securely transmit information between parties, mainly for identity authentication and information exchange. 1. JWT consists of three parts: Header, Payload and Signature. 2. The working principle of JWT includes three steps: generating JWT, verifying JWT and parsing Payload. 3. When using JWT for authentication in PHP, JWT can be generated and verified, and user role and permission information can be included in advanced usage. 4. Common errors include signature verification failure, token expiration, and payload oversized. Debugging skills include using debugging tools and logging. 5. Performance optimization and best practices include using appropriate signature algorithms, setting validity periods reasonably,
How does session hijacking work and how can you mitigate it in PHP?
Apr 06, 2025 am 12:02 AM
Session hijacking can be achieved through the following steps: 1. Obtain the session ID, 2. Use the session ID, 3. Keep the session active. The methods to prevent session hijacking in PHP include: 1. Use the session_regenerate_id() function to regenerate the session ID, 2. Store session data through the database, 3. Ensure that all session data is transmitted through HTTPS.
How to debug CLI mode in PHPStorm?
Apr 01, 2025 pm 02:57 PM
How to debug CLI mode in PHPStorm? When developing with PHPStorm, sometimes we need to debug PHP in command line interface (CLI) mode...
Describe the SOLID principles and how they apply to PHP development.
Apr 03, 2025 am 12:04 AM
The application of SOLID principle in PHP development includes: 1. Single responsibility principle (SRP): Each class is responsible for only one function. 2. Open and close principle (OCP): Changes are achieved through extension rather than modification. 3. Lisch's Substitution Principle (LSP): Subclasses can replace base classes without affecting program accuracy. 4. Interface isolation principle (ISP): Use fine-grained interfaces to avoid dependencies and unused methods. 5. Dependency inversion principle (DIP): High and low-level modules rely on abstraction and are implemented through dependency injection.
How to automatically set permissions of unixsocket after system restart?
Mar 31, 2025 pm 11:54 PM
How to automatically set the permissions of unixsocket after the system restarts. Every time the system restarts, we need to execute the following command to modify the permissions of unixsocket: sudo...
Explain late static binding in PHP (static::).
Apr 03, 2025 am 12:04 AM
Static binding (static::) implements late static binding (LSB) in PHP, allowing calling classes to be referenced in static contexts rather than defining classes. 1) The parsing process is performed at runtime, 2) Look up the call class in the inheritance relationship, 3) It may bring performance overhead.
How to send a POST request containing JSON data using PHP's cURL library?
Apr 01, 2025 pm 03:12 PM
Sending JSON data using PHP's cURL library In PHP development, it is often necessary to interact with external APIs. One of the common ways is to use cURL library to send POST�...
