Christa  Stehr

Christa Stehr

1596756487

Implement the Command Design Pattern in Swift 5

In this article, we will learn about the Command design pattern and implement it in an Xcode Playground.

In short, the Command is a behavioral design pattern that helps us encapsulate actions (commands) and execute them at a later point in time.

It involves the following components:

  • Invoker — an object that executes its commands
  • Command — an action that needs to be performed
  • Receiver — an object that is being acted upon.

Let’s Start

Consider an example of a moderator who reviews an app. The moderation process may have different states: inReviewapproved, and rejected. We want to set specific commands for the moderator and execute them one-by-one with some delay. So let’s start creating the required components.

Receiver

Our receiver is an App class that has a dependency on the ModerationState. Its initial state is submittedForReview:

class App {
	    enum ModerationState {
	        case submittedForReview
	        case inReview
	        case approved
	        case rejected
	    }

	    var moderationState: ModerationState = .submittedForReview
	}

Next, let’s create a Command.

Command

We start with a base class that each specific command with inherit from:

class ModerationCommand {
	    var app: App
	    init(app: App) {
	        self.app = app
	    }

	    public func execute() {}
	}

The command depends on the single App object that we will mutate accordingly in subclasses. Now let’s create these subclasses:

class StartReviewCommand: ModerationCommand {
	    override func execute() {
	        app.moderationState = .inReview
	        print("The app is in review")
	    }
	}

	class RejectCommand: ModerationCommand {
	    override func execute() {
	        app.moderationState = .rejected
	        print("The app was rejected")
	    }
	}

	class ApproveCommand: ModerationCommand {
	    override func execute() {
	        app.moderationState = .approved
	        print("The app was approved")
	    }
	}

As we can see, each command changes the moderationState property of the App object inside the execute() method.

With commands done, now we need to create an Invoker.

#ios #xcode #mobile #programming #swift #command

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Implement the Command Design Pattern in Swift 5
Samanta  Moore

Samanta Moore

1623835440

Builder Design Pattern

What is Builder Design Pattern ? Why we should care about it ?

Starting from **Creational Design Pattern, **so wikipedia says “creational design pattern are design pattern that deals with object creation mechanism, trying to create objects in manner that is suitable to the situation”.

The basic form of object creations could result in design problems and result in complex design problems, so to overcome this problem Creational Design Pattern somehow allows you to create the object.

Builder is one of the** Creational Design Pattern**.

When to consider the Builder Design Pattern ?

Builder is useful when you need to do lot of things to build an Object. Let’s imagine DOM (Document Object Model), so if we need to create the DOM, We could have to do lot of things, appending plenty of nodes and attaching attributes to them. We could also imagine about the huge XML Object creation where we will have to do lot of work to create the Object. A Factory is used basically when we could create the entire object in one shot.

As **Joshua Bloch (**He led the Design of the many library Java Collections Framework and many more) – “Builder Pattern is good choice when designing the class whose constructor or static factories would have more than handful of parameters

#java #builder #builder pattern #creational design pattern #design pattern #factory pattern #java design pattern

Christa  Stehr

Christa Stehr

1596756487

Implement the Command Design Pattern in Swift 5

In this article, we will learn about the Command design pattern and implement it in an Xcode Playground.

In short, the Command is a behavioral design pattern that helps us encapsulate actions (commands) and execute them at a later point in time.

It involves the following components:

  • Invoker — an object that executes its commands
  • Command — an action that needs to be performed
  • Receiver — an object that is being acted upon.

Let’s Start

Consider an example of a moderator who reviews an app. The moderation process may have different states: inReviewapproved, and rejected. We want to set specific commands for the moderator and execute them one-by-one with some delay. So let’s start creating the required components.

Receiver

Our receiver is an App class that has a dependency on the ModerationState. Its initial state is submittedForReview:

class App {
	    enum ModerationState {
	        case submittedForReview
	        case inReview
	        case approved
	        case rejected
	    }

	    var moderationState: ModerationState = .submittedForReview
	}

Next, let’s create a Command.

Command

We start with a base class that each specific command with inherit from:

class ModerationCommand {
	    var app: App
	    init(app: App) {
	        self.app = app
	    }

	    public func execute() {}
	}

The command depends on the single App object that we will mutate accordingly in subclasses. Now let’s create these subclasses:

class StartReviewCommand: ModerationCommand {
	    override func execute() {
	        app.moderationState = .inReview
	        print("The app is in review")
	    }
	}

	class RejectCommand: ModerationCommand {
	    override func execute() {
	        app.moderationState = .rejected
	        print("The app was rejected")
	    }
	}

	class ApproveCommand: ModerationCommand {
	    override func execute() {
	        app.moderationState = .approved
	        print("The app was approved")
	    }
	}

As we can see, each command changes the moderationState property of the App object inside the execute() method.

With commands done, now we need to create an Invoker.

#ios #xcode #mobile #programming #swift #command

Joseph  Murray

Joseph Murray

1624442940

Prototype Design Pattern - Java

Prototype design pattern tutorial

Definition of Prototype pattern

The prototype pattern is a creational design pattern in software development. It is used when the type of objects to create is determined by a prototypical instance, which is cloned to produce new objects.

Where to use the Prototype pattern

If the cost for creating a new object is expensive and costs resources.

#java #design-patterns #code #tutorial #prototype-design-pattern #design pattern

Landscapes Website Design | Nature Landscapes Website Designer

Most landscapers think of their website as an online brochure. In reality of consumers have admitted to judging a company’s credibility based on their web design, making your website a virtual sales rep capable of generating massive amounts of leads and sales. If your website isn’t actively increasing leads and new landscaping contracts, it may be time for a redesign.

DataIT Solutions specializes in landscape website designing that are not only beautiful but also rank well in search engine results and convert your visitors into customers. We’ve specialized in the landscaping industry for over 10 years, and we look at your business from an owner’s perspective.

Why use our Landscapes for your landscape design?

  • Superior experience
  • Friendly personal service
  • Choice of design layout
  • Budget sensitive designs
  • Impartial product choice and advice
  • Planting and lighting designs

Want to talk about your website?
If you are a gardener or have a gardening company please do not hesitate to contact us for a quote.
Need help with your website?
Get in touch

#nature landscapes website design #landscapes website design #website design #website designing #website designer #designer

Houston  Sipes

Houston Sipes

1600430400

10 Free Online Resources To Learn Swift Language

Swift is a fast and efficient general-purpose programming language that provides real-time feedback and can be seamlessly incorporated into existing Objective-C code. This is why developers are able to write safer, more reliable code while saving time. It aims to be the best language that can be used for various purposes ranging from systems programming to mobile as well as desktop apps and scaling up to cloud services.

Below here, we list down the 10 best online resources to learn Swift language.

(The list is in no particular order)

#developers corner #free online resources to learn swift language #learn swift #learn swift free #learn swift online free #resources to learn swift #swift language #swift programming