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- In software engineering, creational design patterns are design patterns that deal with object creation mechanisms, trying to create objects in a manner suitable to the situation. The basic form of object creation could result in design problems or in added complexity to the design due to inflexibility in the creation procedures.
en.wikipedia.org › wiki › Creational_pattern
Top results related to what are software creational patterns?
Top Answer
Answered Nov 07, 2020 · 1 votes
As mentioned, this is kind of an off topic question, as it relates to architecture style more than exact solutions or fixing code issues, and I'm bit on the fence wether to answer it or not.
However, it's still related to a specific technology and ecosystem and therefore might be too narrow for smaller communities. With that in mind I'll list a couple of things you can look into to explore and narrow down exact issues.
Extracting all shared code into "dumb" components
The "dumb" component is NOT an exact reference to presentational components in some old React blogs on the topic, but follows a similar idea. In this case they are dumb about the specific type you pass, but know how to handle any shared logic or interaction.
This is something you've already described as a potential solution but you are worried about having a bunch of switch-case statements inside those components. The ways you avoid those conditional statements are:
- Make the data you pass to those components as similar or generic as possible. You go a long way just by saying data is an object with an id and signature object.
- All handlers and actions specific to the data type should be passed to that component hierarchy from the top-most component that is a "wrapper"/"container" for those shared components. As a simple example imagine you have a list of items with trash icons for deletion. In the container component you would implement logic for deleting an item from the list state-wise, but the rest of the interaction such as the on click handler and a warning modal would be in the shared component hierarchy.
- If any interactions are optional, just make those properties optional. In the example above, if deletion is optional and you don't pass the delete property, the shared component knows not to show the trash icon.
- If you have optional interactions that have 100% shared logic (e.g. is the warning modal used or not) use boolean properties as flags. It's not ideal when you're building the components to have a lot of flags, but is a common feature of many React libraries that offer complex presentational components such as tables
- If you have specific JSX elements or React components that need to be rendered all the way down in the hierarchy, nothing is stopping you to pass those as props. Remember, everything is an object in JavaScript. To keep the same example going, this can be the warning modal's body which can be overriden if that prop is passed.
- Now for the TypeScript part. Components are just classes or functions and you can use generic classes or functions the same way and even supply that generic variable into the subcomponent state and props. And you can be more descriptive with that generic variable and say it extends an abstract class to ensure type safety and pass more info about the shared structure to the shared components.
I'll use the example I've been abusing in the following code snippet instead of your use case because I'm not quite sure of the nature of the actual implementation of your components and I want to present a short version of the idea rather than lead you on a wrong one for your use case.
// abstract class for shared dataabstract class ItemBase { id: number; signature: SignatureInterface;- static isEqual(objA: ItemBase, objB: ItemBase) { return objA.id === objB.id; }}// and there is some concrete class ItemTypeA that extends ItemBase-// container component render<List<ItemTypeA> list={data} removeAction={itemDelete} useDeleteModal={false}/>-// shared list componentimport * as React from 'react';-interface ListProps<TItem extends ItemBase> { list: TItem[]; removeAction: (id: number) => Promise<void>; useDeleteModal?: boolean; deleteModalBody?: React.ReactNode;}-class ListComponent<TItem extends ItemBase> extends React.Component<ListProps<TItem>> {// implementation and sub components like row that have on click handlers etc.// ...-
For an example how this looks in a more complex scenario check out react-table@6
. Note the v6 part, the new one is a complete rewrite using hooks and can also serve as a good example for going into this but using custom hooks rather than standard container props and custom high order components. However, I've personally still not written enough complex hooks to give a good example or suggestion about what to keep in mind.
Possible issues with this approach:
- Component hierarchies can be very deep and you can have a lot of props, consider using Context or react-redux to mitigate this if it becomes an issue, or even develop some of your own high order components to be wrappers where needed. Make sure to keep those parts generic as well.
- There is still just too much data specific code and you end up having to use a bunch of complex wrappers and still the occasional if-else to implement basic things. If this is the issue, the this code isn't a good candidate for abstraction, it just seems similar in structure (which is normal because a lot of hierarchies are similar when you abstract them). Extract what you can and leave the rest as is, forcing patterns and abstractions where they don't fit will cause you more headaches and time wasted than doing everything separately does. This goes double if there is a chance of features getting introduced on only one of those screens and not the others. I've shot myself in the leg with that last one on more than one occasion.
Extend React Class Components
This is in practice a similar idea to the one above. However, instead of passing a bunch of props to a shared component hierarchy, you extend base React components (not abstract, React.Component depends on having a constructor and lifecycle instance methods) that share the shared logic that you then extend. Also, you can still use generics in this case to have type safety in those shared handlers:
interface BaseProps<T extends ItemBase> {}interface BaseState<T extends ItemBase> {}class BaseWindow<T extends ItemBase, TProps extends BaseProps<T>, TState extends BaseState<T>> extends React.Component<TProps, TState> {}-interface MainWindowProps extends BaseProps<MainItem> {}interface MainWindowState extends BaseState<MainItem> {}class MainWindow extends BaseWindow<MainItem, MainWindowProps, MainWindowState> {}-
To call any method of the parent class you just call it via super as you would for regular components. However keep in mind that you'll have to implement the render for every child component individually because each will use different components. This feeds into the fact that inheritance is avoided in React, so think very carefully if your use case calls for using inheritance.
As a side note on this one, even if this is React and TypeScript, the same rulles for any OOP designs apply here and keep Liskov Substitution Principle in mind when doing inheritance and generics.
I've already mentioned Context in the previous example for avoiding passing props really deep on every level, but its use is intended for something much more powerful in combination with the children
prop.
If you've opened the Composition vs Inheritance link you've seen the children prop in action already. It's basically a way to code "wrapper" components that you can use like div-s in render. Nodes that are "boxed" as the "inner JSX" of that component are assigned to this.props.children
If all your shared logic in that shared hierarchy is in the containers (e.g. List in the first example) and not in the final leafs of that component, using this method might be the best option. An example for your use case would be:
<SharedWindow> // same for all objects => does not need a type variable <DocumentViewer<ClerkType> onSignature={this.handleSignature}> {/* DocumentViewer contains the Signature component that needs onSignature which represents various needed handlers on that component or DocumentViewer */} <ClerkDetailsPanel/> // specific Details component </DocumentViewer></SharedWindow>-
Note that this is an example without Context, and you might not even need Context.
Hope some of this helps. I've tried to keep this agnostic for your specific use case and be React specific at the same time so that it can be of help to you and anyone that struggles with a similar issue in the future.
Remember, there is no silver bullet and there are multiple correct ways to do things. It's on you as an engineer to evaluate what suits your use case in the current scenario an foreseeable future the best :)
1/5
Top Answer
Answered Aug 30, 2008 · 3 votes
An ah-ha moment for me for the observer pattern was to realize how closely associated it is with events. Consider a Windows program that needs to acheive loosely communications between two forms. That can easily be accomplished with the observer pattern.
The code below shows how Form2 fires an event and any other class registered as an observer get its data.
See this link for a great patterns resource: http://sourcemaking.com/design-patterns-and-tips
Form1's code:
namespace PublishSubscribe{ public partial class Form1 : Form { Form2 f2 = new Form2();- public Form1() { InitializeComponent();- f2.PublishData += new PublishDataEventHander( DataReceived ); f2.Show(); }- private void DataReceived( object sender, Form2EventArgs e ) { MessageBox.Show( e.OtherData ); } }}-
Form2's code
namespace PublishSubscribe{- public delegate void PublishDataEventHander( object sender, Form2EventArgs e );- public partial class Form2 : Form { public event PublishDataEventHander PublishData;- public Form2() { InitializeComponent(); }- private void button1_Click( object sender, EventArgs e ) { PublishData( this, new Form2EventArgs( "data from form2" ) ); } }- public class Form2EventArgs : System.EventArgs { public string OtherData;- public Form2EventArgs( string OtherData ) { this.OtherData = OtherData; } }}-
Other Answers
Answered Aug 30, 2008 · 3 votes
I use passive view, a flavor of the Model View Presenter pattern, with any web forms like development (.NET) to increase testability/maintainability/etc
For example, your code-behind file might look something like this
Partial Public Class _Default Inherits System.Web.UI.Page Implements IProductView- Private presenter As ProductPresenter- Protected Overrides Sub OnInit(ByVal e As System.EventArgs) MyBase.OnInit(e) presenter = New ProductPresenter(Me) End Sub- Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load presenter.OnViewLoad() End Sub- Private ReadOnly Property PageIsPostBack() As Boolean Implements IProductView.PageIsPostBack Get Return Page.IsPostBack End Get End Property- Public Property Products() As System.Collections.Generic.List(Of Product) Implements Library.IProductView.Products Get Return DirectCast(gridProducts.DataSource(), List(Of Product)) End Get Set(ByVal value As System.Collections.Generic.List(Of Product)) gridProducts.DataSource = value gridProducts.DataBind() End Set End PropertyEnd Class-
This code behind is acting as a very thin view with zero logic. This logic is instead pushed into a presenter class that can be unit tested.
Public Class ProductPresenter Private mView As IProductView Private mProductService As IProductService- Public Sub New(ByVal View As IProductView) Me.New(View, New ProductService()) End Sub- Public Sub New(ByVal View As IProductView, ByVal ProductService As IProductService) mView = View mProductService = ProductService End Sub- Public Sub OnViewLoad() If mView.PageIsPostBack = False Then PopulateProductsList() End If End Sub- Public Sub PopulateProductsList() Try Dim ProductList As List(Of Product) = mProductService.GetProducts() mView.Products = ProductList Catch ex As Exception Throw ex End Try End SubEnd Class-
Other Answers
Answered Aug 30, 2008 · 3 votes
Use code.google.com
For example the search result for "Factory" will get you a lot of cases where the factory Pattern is implemented.
2/5
The main objective of Software Development companies is to provide high quality software products at low cost. Therefore, proper planning is required and proper management is required for the software development process. Thus a proper methodology is important for achieving this type of objectives by the companies and organizations. There are multiple types of Software development methodologies and in this article a detailed knowledge is provided about the Top 15 Software Development Methodologies.
Table of Content
12. Adaptive Software Development...
- What is Software Development Methodology ?
- Top 15 Software Development Methodology
- 1. Agile Methodology
- 2. Behaviour-Driven Development
- 3. Lean Development
- 4. Scrum Methodology
- 5. Waterfall Methodology
- 6. Feature Driven Development (FDD)
- 7. Extreme Programming (XP)
- 8. Spiral Methodology
- 9. Rapid Application Development (RAD)
- 10. Prototyping Methodology
- 11. Rational Unified Process Methodology
- 12. Adaptive Software Development
3/5
Creational design patterns abstract the instantiation process. They help make a system independent of how its objects are created, composed, and represented. A class creational pattern uses inheritance to vary the class that’s instantiated, whereas an object creational pattern will delegate instantiation to another object.
Creational patterns give a lot of flexibility in what gets created, who creates it, how it gets created, and, when.
There are two recurring themes in these patterns:
- They all encapsulate knowledge about which concrete class the system uses.
- They hide how instances of these classes are created and put together.
Important Topics for the Creational Design Pattern
Builder Method Design...
- Example of Creational Design Patterns
- Types of Creational Design Patterns
- Factory Method Design Pattern
- Abstract Factory Method Design Pattern
- Singleton Method Design Pattern
- Prototype Method Design Pattern
- Builder Method Design Pattern
4/5
Creational design patterns abstract the instantiation process. They help make a system independent of how its objects are created, composed, and represented. A class creational pattern uses inheritance to vary the class that’s instantiated, whereas an object creational pattern will delegate instantiation to another object.
Creational patterns give a lot of flexibility in what gets created, who creates it, how it gets created, and, when.
There are two recurring themes in these patterns:
- They all encapsulate knowledge about which concrete class the system uses.
- They hide how instances of these classes are created and put together.
Important Topics for the Creational Design Pattern
Builder Method Design...
- Example of Creational Design Patterns
- Types of Creational Design Patterns
- Factory Method Design Pattern
- Abstract Factory Method Design Pattern
- Singleton Method Design Pattern
- Prototype Method Design Pattern
- Builder Method Design Pattern
5/5
www.geeksforgeeks.org › creational-design-patternCreational Design Patterns - GeeksforGeeks
www.geeksforgeeks.org › creational-design-patternJul 2, 2024 · Creational design patterns abstract the instantiation process. They help make a system independent of how its objects are created, composed, and represented. A class creational pattern uses inheritance to vary the class that’s instantiated, whereas an object creational pattern will delegate instantiation to another object. Creational patterns ...
People also ask
What are creational design patterns in software engineering?
- In software engineering, creational design patterns are design patterns that deal with object creation mechanisms, trying to create objects in a manner suitable to the situation. The basic form of object creation could result in design problems or in added complexity to the design due to inflexibility in the creation procedures.
Creational pattern - Wikipedia
en.wikipedia.org/wiki/Creational_patternWhat are creational design patterns?
- Creational design patterns abstract the instantiation process. They help make a system independent of how its objects are created, composed, and represented. A class creational pattern uses inheritance to vary the class that’s instantiated, whereas an object creational pattern will delegate instantiation to another object.
Creational Design Patterns - GeeksforGeeks
www.geeksforgeeks.org/creational-design-pattern/What are software design patterns?
- Software design patterns are essential tools for developers, providing proven solutions to common problems encountered during software development. This tutorial introduces the concept of design patterns, explains their importance, and explores various types, including creational, structural, and behavioral patterns.
Software Design Patterns Tutorial - GeeksforGeeks
www.geeksforgeeks.org/software-design-patterns/How do creational design patterns solve a problem?
- Creational design patterns solve this problem by somehow controlling this object creation. Creational design patterns are composed of two dominant ideas. One is encapsulating knowledge about which concrete classes the system uses. Another is hiding how instances of these concrete classes are created and combined.
Creational pattern - Wikipedia
en.wikipedia.org/wiki/Creational_patternen.wikipedia.org › wiki › Creational_patternCreational pattern - Wikipedia
en.wikipedia.org › wiki › Creational_patternIn software engineering, creational design patterns are design patterns that deal with object creation mechanisms, trying to create objects in a manner suitable to the situation. The basic form of object creation could result in design problems or in added complexity to the design due to inflexibility in the creation procedures.
www.baeldung.com › creational-design-patternsIntroduction to Creational Design Patterns | Baeldung
www.baeldung.com › creational-design-patternsJan 11, 2024 · In software engineering, a Design Pattern describes an established solution to the most commonly encountered problems in software design. It represents the best practices evolved over a long period through trial and error by experienced software developers.
refactoring.guru › design-patterns › creational-patternsCreational Design Patterns - refactoring.guru
refactoring.guru › design-patterns › creational-patternsCreational design patterns provide various object creation mechanisms, which increase flexibility and reuse of existing code. Provides an interface for creating objects in a superclass, but allows subclasses to alter the type of objects that will be created.
www.geeksforgeeks.org › software-design-patternsSoftware Design Patterns Tutorial - GeeksforGeeks
www.geeksforgeeks.org › software-design-patternsJul 15, 2024 · This tutorial introduces the concept of design patterns, explains their importance, and explores various types, including creational, structural, and behavioral patterns. By understanding and applying these patterns, developers can create more robust, maintainable, and scalable software systems.
dev.to › sumanpal97 › understanding-creationalUnderstanding Creational Design Patterns: A Comprehensive ...
dev.to › sumanpal97 › understanding-creationalSep 28, 2023 · Creational Design Patterns are a distinct category of design patterns that focus on the creation of objects and their associated mechanisms. These patterns offer techniques for object creation that conceal the underlying intricacies of instantiation and initialization.
en.wikipedia.org › wiki › Software_design_patternSoftware design pattern - Wikipedia
en.wikipedia.org › wiki › Software_design_patternIn software engineering, a design pattern describes a relatively small, well-defined aspect (i.e. functionality) of a computer program in terms of how to write the code. Using a pattern is intended to leverage an existing concept rather than re-inventing it.
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