I am full-stack developer and currently study in software engineering in the university 2 course. Currently I am working on a Bookstore project using spring boot for back and React for frontend. So I need to implement 5 software design patterns in my project. However I don't now how to do such implementations and not yet experienced. So I need your help. How I can implement this?
First of all I am not here to demotivate you or anything else, what I will suggest you to start making a class diagram and from that class diagram you will notice somethings that will look weird to you, so the things that will look weird to you will be things that will required the implementation of the Design Patterns.
There are basically three types of Design Patterns Creational, Observer and Behavioral. So, as soon as you will create the Class Diagram, you will notice some base cases such as one class should use the single database object or same logic on a single time that is the place where you will be using the Singleton Design Pattern.
Let's say you have created a Class Diagram such that one parent class should not be able to create the objects of other class but the subclasses should do that kind of work, so this is the classic example of Factory Method design pattern and so and so on.
I wish you best of luck for your project as well.
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So basically, I mean something like UML for designing classes in Object-Oriented programming.
How can we use a diagramming software to design (model) our UIs (Components, props, states, event etc) before writing any actual code?
You can use the https://balsamiq.cloud/ for creating the wireframes of UI before starting the actual code.You can create the mobile view screens for different mobile versions in that.Later you can work on the screens wise.
Once the UI is done you may get the clear idea of what is needed in reactjs states and props values.
Pen and paper ... whiteboard. It might sound like I'm kidding. But I find this to be the best way to model your app. When I'm done with a whiteboard diagram, I take a photo if I need to share it.
It does two big things, imo: 1. it keeps things simple so you get the important stuff figured out without overcomplicating things so you get started coding; 2. it doesn't look too official or polished so you remember it's just a sketch. When it comes time to write your code, your established patterns and conventions should dictate your app architecture and your "wireframes" should just be a reference to look back on.
Again, just my own opinion. There is no single answer to your question.
I am new to Zend Framework and currently struggling with the implementation of Model. Actually, what I want is as follows:
I have two tables (am using MySQL):
Musicians(id, name)
Albums(id, musician_id, album_name)
Now, I want to design the model, so that I can create an efficient join query in there.
I have tried many things, but am unclear about various things. For example, currently I have created a Table class (which extends Zend_Db_Table_Abstract), a model class and a model_mapper class. I am not sure, what code to put in which file and how actually I am going to call the model functions (containing the query result) in the action function in controller.
Any help is highly appreciated.
There is no single answer to this question. The best code to put in each class is based on the application logic your requirements call for.
There are methodologies to guide object-oriented design:
GRASP
SOLID
Domain-Driven Design
This free e-book has an introduction to DDD: Domain-Driven Design Quickly
I'm starting to make my first C program in awhile using GTK+. I've learned C to some extent and I've worked with PyGTK, so I have a decent understanding of both. But, I've never created GUI program with C. Though it worked, my last GUI program was a bit of a mess because the program logic was all mixed in with the GUI stuff. I've read that it's best to write the GUI and program logic in a decoupled way so that if you switch GUI libraries, it'd be rather painless.
Is this right? Let's say I'm adding an item to a visual list. Do I have a function that adds the item to a logical list and run that in a function that looks at that list and then updates the gui?
For example,
void new_item_button_handler()
{
add_item_to_array() /* Code dealing with program logic*/
/*
* Code here to look at array and update visual list using GUI commands
*/
}
What's the general process for doing this?
Any advice would be appreciated!
EDIT:
Thanks for the advice regarding MVC. Could you perhaps explain that in the context of the example I gave? There's a lot of info on MVC out there, and I'm having a hard time trying to figure out how it applies to my code example here.
I think you're looking for the Model-View-Controller design pattern.
traditionally this is solved with an MVC pattern. however if you are not disciplined, you will see business logic creeping into your view layer.
design your package structure as best you can so that everything fits neatly into a model, view, and controller packages. make sure you have well define interfaces for sharing data between packages. make every effort to design the packages in a way that each individual package will be testable and mostly usable without depending on the other 2.
i would also encourage you to look at the IOC pattern. this will help when connecting all your packages together. it will also help during testing when you need to mock up some stub classes to test 1 package independently of the other 2. IOC is the "wiring" of your application, it lets you mix and match objects.
Couple of year ago I when to work for company as web developer. It has my first Sirius web development job, (ASPx/C#) so it has very exciting and I learned a lot about that world, from the developer point of view.
In that group we had a concept for the pages where loaded in the page UC’s (User controls), I don’t know if it’s the same in every web development team with every language, I’ll assume it is so.
The contract ended and I came back to develop win32 “winForm” application.
But since them I have tried to apply the same principle for my win32 development I learn there, meaning having bunch of UC’s (Visual User controls) that I load in the form.
They are regular visual components, not loaded in the toolbox, code is available in the project, but the component is not developed in the form, they are loaded there.
I would like to know opinions about this approach, what other are doing similar or better to this And improvements that can help us to speed up development and increase code reuse, because that is what this is all about.
If you're using the layout components in Winforms, this might be an acceptable approach although I think the thing that distinguishes the web and Windows Forms (note: NOT WPF!) is that in the former you do a lot of "compositing" which is why the UserControl concept is so useful whereas in the latter you operate on very sophisticated controls (e.g. 3rd party - in my last gig we used an incredible grid control via a small company called Infralution)
The main problem I would see is with layouts since the rendering model is a little different than the web. I know nothing about your application but if it "works" that is what is most important. I assume in this case you use things like the FlowLayoutPanel and the TableLayoutPanel properly.
If you want to go a more canonical route, take a look beyond simply creating components at how you can use the inheritance model to composite your application in a more robust way - having a base Form class that has containers for where your "UserControl" type components go and then using some kind of interface based dependency injection to swap them out while the application is running.
Finally, take a look at some of the open source Windows Forms applications out there to see if you're being too hard on yourself since common UI and reusable components are a goal in every application. Even though I've always thought Microsoft's Patterns & Practices stuff teetered towards being bloated, there are some good ideas and you should study some of the approaches of the Composite UI Application Block they put out.
Okay, not finally, there's one more thing I'd like to add: take a long hard look at WPF which will bring back a lot of the concepts from your web development days and give you that kind of power in a desktop application.
I've recently asked a question on StackoverFlow about the MVC: Can the MVC Design Pattern / Architectural pattern be used in Desktop Application Development?
Based on the answer provided I started research on how this would be implemented in a Windows form Application. I came upon the following CodeProject article: http://www.codeproject.com/KB/cs/model_view_controller.aspx
In the comments below the article, certain users argue that (although this is a good article) it is actually the observer pattern. First, but less important, question is does anyone agree or disagree with that and why?
Regarding the second and more important question: I'm trying to build a small task list program in .NET. It will be very tiny and hopefully fast. In general, what would be a better architecture for such a project? The Observer Pattern or the MVC Pattern? Or another pattern?
Thank you
usually the model in an mvc (http://en.wikipedia.org/wiki/Model-view-controller) is an observable/subject (http://en.wikipedia.org/wiki/Observer_pattern#Subject), while the views are observers (http://en.wikipedia.org/wiki/Observer_pattern#Observer). also see: mvc in http://webcourse.cs.technion.ac.il/234321/Winter2005-2006/ho/WCFiles/08-Design-Patterns.ppt
(The article is not an example of MVC AFAIK for the simple reason that there is no controller.. it is more close to .net data binding if you ask me.)
MVC is not the Observer pattern. MVC is concerned with separation of concerns. The Model, the View and the Controller all do one job and trust the others to do theirs. In a way, the Controller 'directs' the view and tells it how to react to a change (Pure MVC). The controller also interacts with the model appropriately (whose responsibility is to encapsulate data and enforce constraints/rules). In MVC, the controller is the starting point for all activities - user input is received by the controller first.. However there are variants like MVP, where the user is input is received by the view first and then pushed/synched with the presenter.
The Observer pattern is where you want to watch another object for a change in state. So you could say .net events follow the observer pattern
If its really tiny, forget about patterns and just code it up without worrying about the architecture... Follow the heuristics/principles of good design
http://butunclebob.com/ArticleS.UncleBob.PrinciplesOfOod
http://mmiika.wordpress.com/oo-design-principles/
If you run into design issues or it starts to get all messy, then bring in the pattern battalions.
I would agree that the article is not MVC. Its more of an implementation of observer pattern. Observer pattern in .NET can be implemented by using events, which was the case of the article.
MVC requires a controller class that controls what action to execute upon a request made from either the model, or the view. Applying MVC is a very good programming practice as it greatly promotes separation of concern. You will have a cleaner, more extensible, and more testable app with mvc. Another point to note, you can still apply observer pattern to an MVC app. They will not contradict each other.
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To answer your second question: which pattern is the best? I think the way you approach software development is rather wrong. You shouldn't worry too much about those things yet, not until you've hit a problem. e.g. If this object changes state I need these other objects to react to it, hence I would implement an observer pattern.
If I were you I would start on the model side first, and then takes things from there.