国产av日韩一区二区三区精品,成人性爱视频在线观看,国产,欧美,日韩,一区,www.成色av久久成人,2222eeee成人天堂

Home Backend Development PHP Tutorial Designer Job Resume Template PHP Design Pattern Introduction Value Object Pattern Page 1/5

Designer Job Resume Template PHP Design Pattern Introduction Value Object Pattern Page 1/5

Jul 29, 2016 am 08:37 AM


For example: An object is usually used to describe a date, a number or currency. Class definitions for dates, integers, or dollars are easy to use, fast, easy to encapsulate, and easy to copy, compare with each other, and even create.
On the surface, these objects with simple descriptions are easy to execute: they have very few statements and make no difference whether they apply to Customer or SKU when constructing the class. This idea seems correct, but the so-called "seems correct" can easily produce some bugs.
Please look at the code below, which is the definition and execution of an object that pays employees wages in US dollars. In most cases, it operates without problems. (This class was named BadDollar because it was buggy). Think about it and see if you can find a bug in it.
// PHP5
class BadDollar {
protected $amount;
public function __construct($amount=0) {
$this->amount = (float)$amount;
}
public function getAmount() {
return $ this->amount;
}
public function add($dollar) {
$this->amount += $dollar->getAmount();
}
}
class Work {
protected $salary;public function __construct() {
$this->salary = new BadDollar(200);}
public function payDay() {
return $this->salary;
}
}
class Person {
public $wallet;
}
function testBadDollarWorking() {
$job = new Work;
$p1 = new Person;
$p2 = new Person;
$p1->wallet = $job->payDay();
$this-> assertEqual(200, $p1->wallet->getAmount());
$p2->wallet = $job->payDay();
$this->assertEqual(200, $p2-> wallet->getAmount());
$p1->wallet->add($job->payDay());
$this->assertEqual(400, $p1->wallet-> getAmount());
//this is really bad — actually 400
$this->assertEqual(200, $p2->wallet->getAmount());
//this is really bad — actually 400
$ this->assertEqual(200, $job->payDay()->getAmount());
}
So, what is the bug? If you don't see the problem intuitively in the above code example, here's a tip: Employee object $p1 and object $p2 use the same BadDollar object instance.
First, instances of class Work and class Person have been created. Then, assuming that each employee initially has an empty electronic wallet, the employee's electronic wallet Person:wallet is assigned through the object resource variable returned by the Work::payDay() function, so it is set to an object instance of the BadDollar class.
Do you still remember PHP5’s object assignment method? Because of the way object assignment is handled in PHP5, although the three seemingly different object instances $job::salary, $p1::wallet and $p2::wallet use different "identifiers", in fact , they are all assigned to the same object instance.
Therefore, in the next operation of distributing wages (PayDay represents the day when wages are paid, here represents the action of distributing wages), using $job->payDay() originally only wanted to increase the salary of $P1, but unexpectedly The first $P2 was also distributed. Moreover, this action also changes the amount of the basic salary of the job. Therefore, the detection of the last two values ??reports an error.
Value Object PHP5 Unit Test
1) Equal expectation fails because [Integer: 200] differs from [Float: 400] by 200
in testBadDollarWorking
in ValueObjTestCase
2) Equal expectation fails because [Integer: 200] differs from [Float: 400] by 200
in testBadDollarWorking
in ValueObjTestCase
FAILURES!!!

Current page 1/5 12345Next page

The above introduces the designer resume template. PHP design pattern introduction value object pattern page 1/5, including the content of the designer resume template, I hope it will be helpful to friends who are interested in PHP tutorials.

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undress AI Tool

Undress AI Tool

Undress images for free

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

What are some best practices for versioning a PHP-based API? What are some best practices for versioning a PHP-based API? Jun 14, 2025 am 12:27 AM

ToversionaPHP-basedAPIeffectively,useURL-basedversioningforclarityandeaseofrouting,separateversionedcodetoavoidconflicts,deprecateoldversionswithclearcommunication,andconsidercustomheadersonlywhennecessary.StartbyplacingtheversionintheURL(e.g.,/api/v

How do I implement authentication and authorization in PHP? How do I implement authentication and authorization in PHP? Jun 20, 2025 am 01:03 AM

TosecurelyhandleauthenticationandauthorizationinPHP,followthesesteps:1.Alwayshashpasswordswithpassword_hash()andverifyusingpassword_verify(),usepreparedstatementstopreventSQLinjection,andstoreuserdatain$_SESSIONafterlogin.2.Implementrole-basedaccessc

What are the differences between procedural and object-oriented programming paradigms in PHP? What are the differences between procedural and object-oriented programming paradigms in PHP? Jun 14, 2025 am 12:25 AM

Proceduralandobject-orientedprogramming(OOP)inPHPdiffersignificantlyinstructure,reusability,anddatahandling.1.Proceduralprogrammingusesfunctionsorganizedsequentially,suitableforsmallscripts.2.OOPorganizescodeintoclassesandobjects,modelingreal-worlden

What are weak references (WeakMap) in PHP, and when might they be useful? What are weak references (WeakMap) in PHP, and when might they be useful? Jun 14, 2025 am 12:25 AM

PHPdoesnothaveabuilt-inWeakMapbutoffersWeakReferenceforsimilarfunctionality.1.WeakReferenceallowsholdingreferenceswithoutpreventinggarbagecollection.2.Itisusefulforcaching,eventlisteners,andmetadatawithoutaffectingobjectlifecycles.3.YoucansimulateaWe

How can you handle file uploads securely in PHP? How can you handle file uploads securely in PHP? Jun 19, 2025 am 01:05 AM

To safely handle file uploads in PHP, the core is to verify file types, rename files, and restrict permissions. 1. Use finfo_file() to check the real MIME type, and only specific types such as image/jpeg are allowed; 2. Use uniqid() to generate random file names and store them in non-Web root directory; 3. Limit file size through php.ini and HTML forms, and set directory permissions to 0755; 4. Use ClamAV to scan malware to enhance security. These steps effectively prevent security vulnerabilities and ensure that the file upload process is safe and reliable.

How can you interact with NoSQL databases (e.g., MongoDB, Redis) from PHP? How can you interact with NoSQL databases (e.g., MongoDB, Redis) from PHP? Jun 19, 2025 am 01:07 AM

Yes, PHP can interact with NoSQL databases like MongoDB and Redis through specific extensions or libraries. First, use the MongoDBPHP driver (installed through PECL or Composer) to create client instances and operate databases and collections, supporting insertion, query, aggregation and other operations; second, use the Predis library or phpredis extension to connect to Redis, perform key-value settings and acquisitions, and recommend phpredis for high-performance scenarios, while Predis is convenient for rapid deployment; both are suitable for production environments and are well-documented.

What are the differences between == (loose comparison) and === (strict comparison) in PHP? What are the differences between == (loose comparison) and === (strict comparison) in PHP? Jun 19, 2025 am 01:07 AM

In PHP, the main difference between == and == is the strictness of type checking. ==Type conversion will be performed before comparison, for example, 5=="5" returns true, and ===Request that the value and type are the same before true will be returned, for example, 5==="5" returns false. In usage scenarios, === is more secure and should be used first, and == is only used when type conversion is required.

How do I perform arithmetic operations in PHP ( , -, *, /, %)? How do I perform arithmetic operations in PHP ( , -, *, /, %)? Jun 19, 2025 pm 05:13 PM

The methods of using basic mathematical operations in PHP are as follows: 1. Addition signs support integers and floating-point numbers, and can also be used for variables. String numbers will be automatically converted but not recommended to dependencies; 2. Subtraction signs use - signs, variables are the same, and type conversion is also applicable; 3. Multiplication signs use * signs, which are suitable for numbers and similar strings; 4. Division uses / signs, which need to avoid dividing by zero, and note that the result may be floating-point numbers; 5. Taking the modulus signs can be used to judge odd and even numbers, and when processing negative numbers, the remainder signs are consistent with the dividend. The key to using these operators correctly is to ensure that the data types are clear and the boundary situation is handled well.

See all articles