CakePHP Applications being made in our company tends to become unmaintainable as it becomes more complex. I figured that one specific reason is inheritance which makes the functions in child classes depends a lot on it's parent classes and vice-versa (implementing template method pattern). Why is CakePHP designed this way and not friendly in using Dependency Injection, Strategies, or Factory patterns?
There is not such a bad design as you claim in the framework. Sure, there are probably things that could be done better but I would like to see a more substantial critic including solid arguments and examples. I assume you're not using the framework as it was intended.
Let me quote the first paragraph from this page.
According to Eric Evans, Domain-driven design (DDD) is not a technology or a methodology. It’s a different way of thinking about how to organize your applications and structure your code. This way of thinking complements very well the popular MVC architecture. The domain model provides a structural view of the system. Most of the time, applications don’t change, what changes is the domain. MVC, however, doesn’t really tell you how your model should be structured. That’s why some frameworks don’t force you to use a specific model structure, instead, they let your model evolve as your knowledge and expertise grows.
You're not showing code (for a reason?) so I guess your problem comes from stuffing everything into the table objects in src/Model/Table/ or doing something similar.
But you're totally free to create a folder structure like
/src/Service
/src/Model/Domain
and then simply instantiate services as you need them in your controller actions. A service could be for example \App\Service\User\Registration and using objects from App\Model\Domain\User.
I agree that the framework in fact doesn't provide any recommendation or template structure for how this could look like. For exactly this topic there is a discussion going on here. Because of a lack of such a structure I've started working on a plugin that provides this. The plugin doesn't require but suggest the usage of DI containers for the people who want them.
Given the whole fancy topic around DI and DDD so far I would say there is not the one way to get things right but different paths as long as the code is easy to maintain. And honestly, as long as this goal is archived I really don't care about how you call it. :) I think many people tend do make this topic to academic instead of simply trying to be practical.
Not everybody is even needing that structure. It depends on if you're building a RAD CRUD application or a more complex app. Not every application needs a DDD approach. There are so many shades of gray when it comes to design the business layer, no matter how the framework would do it, somebody would always complain about it.
I personally almost never missed a DI container in CakePHP, not even in the biggest project having more than ~560 database tables which was a hospital management solution and it just worked well.
I would suggest you to ask a more specific question about your approach how you structured your code and showing your structure and code and then asking for advice on how to improve it instead of blaming the tool you're using in the first place without providing context.
Unfortunately CakePHP v3 can not compare to the Zend3/Laminas, Symfony or Laravel.It is 7-8 years behind the other frameworks.If you are using cake for years or it is your 1st and last framework it is normal to not realise that.But if you have to use it after Zend 3... cake seems like really bad ecosystem.
Bad documentation
Bad ORM
Poor Routing system
Bad Templating engine
Bad idea to mix Data Mapper and Active Record
DIC is totally missing
Components - not good but not terrible
...
And many more thinks that should not be underestimated like - lack of GOOD tutorials, pluigns/addons/packages
The above thinks make developers to follow bad practices that adds a lot of technical depth.
If you care just for - it works! But not how it works and why it is bad, cake will fit ok for you.
Cake can not scale as good as Symfony/Laminas if you are doing big project.(yea AWS/GC can help for scaling a lot of thinks but not for scaling source code)
Cake doesn't allow you rapid development like Laravel/Symfony for decent project.
I'm wondering who and WHY would start a new project today using Cake as it has zero benefits over the other frameworks.
Probably only devs who used only Cake for last decade and do not want to start learning new technologies or devs that thinks SOLID is just a fancy hype with zero benefits like design patterns, DRY and KISS
CakePHP framework supplies user interaction with databases using Active record, it means that exist a high coupling between business layer and database layer which has negative effects in unit testing and because of that the framework is not friendly with Dependency Injection. The same issue happens with Factory pattern, high coupling mentioned before makes more difficult use simulated objects in unit testing.
Hope it helps!
Alberto
Related
I needed to get the root item of a TreeView. The obvious way to get it is to use the getRoot() on the TreeView. Which I use.
I like to experiment, and was wondering if I can get same root, buy climbing up the tree from a leaf item (a TreeItem), using recursively getParent() until the result is NULL.
It is working as well, and, in my custom TreeItem, I added a public method 'getRoot()' to play around with it. Thus finding out this method does already exist in parent TreeItem, but is not exposed.
My question : Why would it not be exposed ? Is is a bad practice regarding OOP / MVC architecture ?
The reason for the design is summed up by kleopatra's comment:
Why would it not be exposed I would pose it the other way round: why should it? It's convenience api at best, easy to implement by clients, not really needed - adding such to a framework/toolkit tends to exploding api/implementation to maintain.
JavaFX is filled with decisions like this on purpose. A lot of the reasoning is based on experience (good and bad) from AWT/Spring. Just some examples:
For specifying execution on the UI thread, there is a runLater API, but no invokeAndWait API like Swing, even though it would be easy for the framework to provide such an API and it has been requested.
Providing an invokeAndWait API means that naive (and experienced :-) developers could use it incorrectly to accidentally deadlock threads.
Lots of classes are final and not extensible.
Sometimes developers want to extend classes, but can't because they are final. This means that they can't over-ride a lot of the built-in tested functionality of the framework and accidentally break it that way. Instead they can usually use aggregation over inheritance to do what they need. The framework forces them to do so in order to protect itself and them.
Color objects are immutable.
Immutable objects in general make stuff easier to maintain.
Native look and feels aren't part of the framework.
You can still create them if you want, and there are 3rd party libraries that do that, but it doesn't need to be in the core framework.
The application programming interface is single threaded not multi-threaded.
Because the developers of the framework realized that multi-threaded UI frameworks are a failed dream.
The philosophy was to code to make the 80% use case easier and the the 20% use case (usually) possible, using additional user or 3rd party code, while making it difficult for the user code to accidentally (or intentionally) break the framework. You just stumbled upon one instance of an application of this philosophy.
There are a whole host of catch-phrases that you could use to describe the reason for this design approach. None of them are OOP or MVC specific. The underlying principles have been around far longer than software engineering, they are just approaches towards work and engineering in general. Here are some links if interested:
You ain't going to need it YAGNI
Minimal viable product MVP
Worse-is-better
Muntzing
Feature creep prevention
Keep it simple stupid KISS
Occam's razor
Let's say I've made a list of concepts I'll use to draw my Domain Model. Furthermore, I have a couple of Use Cases from which I did a couple of System Sequence Diagrams.
When drawing the Domain Model, I never know where to start from:
Designing the model as I believe the system to be. This is, if I am modelling a the human body, I start by adding the class concepts of Heart, Brain, Bowels, Stomach, Eyes, Head, etc.
Start by designing what the Use Cases need to get done. This is, if I have a Use Case which is about making the human body swallow something, I'd first draw the class concepts for Mouth, Throat, Stomatch, Bowels, etc.
The order in which I do things is irrelevant? I'd say probably it'd be best to try to design from the Use Case concepts, as they are generally what you want to work with, not other kind of concepts that although help describe the whole system well, much of the time might not even be needed for the current project. Is there any other approach that I am not taking in consideration here? How do you usually approach this?
Thanks
Whether DDD, or not, I would recommend with determining the ubiquitous language (UL) by interviewing the product owner(s). Establishing communication in a way that will have you and the product owners speaking the same language not only aides in communication, but being able to discuss the project in common terms tends to help the domain model define itself.
So, my answer is basically to discuss, listen, and learn. Software serves a need. Understanding the model from the viewpoint of the experts will lay the solid groundwork for the application.
I'd start by a drawing a class diagram with all the relationships and implement only the classes that are necessary according to the requirements of your application.
You can use an anemic approach (attributes plus getters and setters) to keep things simple and avoid the step of writing business logic in the same step. With an anemic model, the logic would go into a corresponding Service class. That way you can consider Use Cases later on.
I know some people don't appreciate this way of doing things but it does help with maintenance and avoids some dependency issues.
Answer to devoured elysium's question below:
In terms of analysis, starting with Use cases (What) and then proceeding to the class diagram (How) sounds like a good rule of thumb. Personally, I'd do the Sequence diagram (When and Who?) afterwards, as you'd need to know between which processes/objects messages need to be sent.
Beyond that my take on things is that UML is simply a way to model a system/project and not a methodology by itself (unlike Merise, RAD, RUP, Scrum, etc.). There is nothing stopping someone starting off with any diagram as long as they have the sufficient information to complete it. In fact, they should be done simultaneously since each of the diagrams is a different perspective of the same system/project.
So, all in all it depends on how you go about the analysis. During my studies I was taught the rigid waterfall approach, where you do a complete analysis from start to finish before producing some code. However, things can be different in practice, as the imperative might be to produce a working application in the least time possible.
For example, I was introduced to the Scrum methodology recently for an exercise involving the creation of a web site where people can post their fictions. As there was a time constraint and a clear vision of what should be achieved, we started right away with a bare bones class diagram to represent the domain model. The Use cases were then deduced from a series of mock screens we'd produced.
From memory, the classes were Story, Chapter, User and Category. This last class was phased out in favour of a more flexible Tag class. As you'd imagine, the complete class diagram of the existing project would be much more complex due to applying domain driven design and the specificities of the Java programming language.
This approach could be viewed as sloppy. However, a web site like this could easily be made in a couple of weeks using an iterative process and still be well designed. The advantage an iterative process has over the waterfall approach is that you can continually adjust requirements as you go. Frequent requirements changing is a reality, as people will often change their minds and the possibility of producing a working application after each iteration allows one to stay on course so to speak.
Of course, when you're presenting a project to a client, a complete analysis with UML diagrams and some mock screens would be preferable so they have an idea of what you're offering. This is where the UML comes in. Once you've explained some of the visual conventions, an individual should be able to understand the diagrams.
To finish off, if you're in the situation where you're trying to determine what a client wants, it's probably a good idea to gradually build up a questionnaire you can bring with you. Interviewing a person is the only way you can determine what concepts/features are really needed for an application, and you should expect to go back in order to clarify certain aspects. Another tip would be to do some quick research on the web when you're confronted with a subject matter you're unfamiliar with.
In your example, this would be to go through the basics of anatomy. Among other things, this will help you decide what the model should contain and what granularity it should have (What group of organs should be considered? How precise does it need to be? Do only the organs need to modeled or should they be decomposed into their constituents like tissues, cells, chemical composition, etc. ?).
I think the place to start would be whatever feels logical and comfortable. It's probably best to start with the use cases, as they give you clear direction and goals, and help you avoid YAGNI situations. Given that you should be trying to develop a strong domain model, it shouldn't really matter, as the whole picture of the domain is important.
I would like to share my experience for such type of situations. I usually start with writing tests and code. And try to cover one end to end use case. This gives me fair enough idea about problem and at the end I also have something working with me which I can show case to my client. Most of the time subsequent stories build on top of previous one, but it also happens to me that subsequent stories require changes in the previous model I came up with. But this does not impact me as I already have good test coverage. In this way I came up with the model which fits for the current problem, not the model which maps the real world.
You start with Business Requirements which can be formalized or not. If formalized you would use Use Case Diagrams.
For example here are use case diagrams for an e-commerce app:
http://askuml.com/blog/e-commerce/
http://askuml.com/files/2010/07/e-commerce-use-case.jpg
http://askuml.com/files/2010/07/e-commerce-use-case2b.jpg
From these use cases, you can naturally deduce the business entities: product, category of product, shopping cart, ... that is start to prepare class diagrams.
This is best practice in many methodologies but this is also just common sense and natural.
Short answer
Pick a use case, draw some collaboration diagram (and a class diagram) to realize the domain objects involved. Concentrate only on those objects participated in order to accomplish use case goal. Write TDD test case to set the expectation and gradually model your domain classes to meet the expectations. TDD is very helpful to understand the expected behaviors and it helps to get the cleaner domain model. You will see your domain evolve gradually along with the TDD expectations.
Long answer
My personal experience with DDD was not easy. That was because we didn't have necessary foundations in the first place. Our team had many weak points in different areas; requirements were not captured properly and we only had a customer representative who was not really helpful (not involved). We didn't have a proper release plan and developers had a lack of Object Oriented concepts, best principles and so on. The major problem we had was spending so much time on trying to understand the domain logic. We sketched many class diagrams and we never got the domain model right, so we stopped doing that and found out what went wrong. The problem was that we tried too hard to understand the domain logic and instead of communicating we made assumptions on the requirements. We decided to change our approach, we applied TDD, we started writing the expected behavior and coded the domain model to meet the TDD's expectations. Sometimes we got stuck writing TDD test cases because we didn't understand the domain. We straight away talked to the customer representative and tried to get more input. We changed our release strategy; applied agile methodology and release frequently so that we got real feedback from the end user. However, needed to ensure the end user expectation was set at the right level. We refactored based on the feedback, and in that way the domain model evolved gradually. Subsequently, we applied design patterns to improve reusability and maintainability. My point here is that DDD alone cannot survive, we have to build the ecosystem that embraces the domain, developers must have strong OOP concepts and must appreciate TDD and unit test. I would say DDD sits on top of all the OOP techniques and practices.
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I work at a web development shop so naturally we deal with user profiles. When dealing with one of our sites I noticed that there was no 'User' class, which struck me as odd since we certainly have users. Instead the site relies on interacting with DataRows (this is C#) returned through static methods with little to no instantiation. I asked my boss about creating a class for users and his response was that since the objects have to be rebuilt so much its often not worth it.
I am relatively new to web development and it does seem like a bit of a waste to have to instantiate objects each time the page is rebuilt but on the other hand I've always found object oriented programming to be useful. So I'm curious for some opinions, how much do you guys use OOP in web development?
The only time I don't use OOP is when:
I'm creating a simple project to test some logic. This usually leads to creating the right classes...
I'm using Classic ASP (been awhile, thank god).
I'm not programming.
edit
3+ years after posting the above; I'm appending a bit to my answer.
OOP is great and allows us a tremendous amount of flexibility for having multiple systems interacting with the same data / logic. However, there is certainly a situation in which you wouldn't want to bother loading up a lot of objects.. Namely, when you are simply pulling data for tabular display.
Querying a database and getting a simple record set back that is immediately emitted to the browser usually doesn't need OOP involved. As a matter of fact you might want to sidestep OOP completely as tabular data usually involves a roll up of other information (sums of child records) and you normally don't want to pull more data from the database than what you are actually using. ie. if you are only showing the name and email you probably don't want to grab the user name as that is just wasted cycles.
Now, putting information into a DB usually involves making sure that certain business logic is followed. For example that the username follows certain rules. In those situations leveraging an OOP style keeps things a bit more encapsulated and easily transferred between systems.
So, looking at the specific example: I wouldn't bother with more than handing a datatable to a repeater when pulling data; but I would have a user class for when I'm going to create a new one or operate on that user to make sure the business rules are properly followed.
One question: does the data need to be coupled with function/method calls? If not, OOP is not necessary.
Your best approach might be to find an empty whiteboard, create a high level model using Object Oriented Design, then with Functional Design, then with Procedural. You might surprise yourself (and others) with the results. The same language can be used in vastly different ways depending on the project. As mentioned by #wj. OOP is just a paradigm, don't be afraid to step outside of your comfort zone and design using a different paradigm.
Taking time to design using different paradigms will also help you when you approach your boss to discuss why you should or should not use the current paradigm. Most bosses will appreciate that you spent the time to research before approaching them with an idea -- this isn't to say they'll accept your idea, but being knowledgable going in will potentially get you a few extra minutes of his/her attention.
IMHO (don't take this personally), "Object Oriented Programming" has fallen with the likes of "Web 2.0" -- a buzzword of sorts, which is unfortunate; you now see developers forcing OOP where it would be better suited to use FP or PP.
The best professional advice I can give is to design (high level at first, then dive down) in multiple paradigms (do your best not to be biased -- keep an open mind) and decide which one best addresses the way your application works. In my 15 years experience, 75+% of the time I find OOP to be unnecessary, although my current project is strictly OOP.
A more important/relevant question would be, "Does Object Oriented Design have a place in my current web development?"
Although objects make it easier for some programmers to develop, I've read the perfect example of how to build an entire website without OOP. Not once ounce. Check out the last page in a 20 page series entitled Clean PHP:
http://okmaya.com/clean-php/clean-php-step-20/
Super easy to follow, clean way of building an entire website. No confusing OOP, no super nested folder, no crazy spaghetti code to follow for hours... Just simple, clean, and well laid out functions that do EVERYTHING you need, without the use of OOP. And this example has everything from login/registration credentials, an admin section (CMS), even database fixtures to get you started, a search function that uses mapquest API to do zip code / lat-long lookups... I mean it has EVERYTHING for a core project, or website.
Why bother with OOP? Clean, and properly structured procedural code is great!
On the topic of OOP. I remember another fad that everyone thought it was cool, and everyone did it, but then found out that smoking gave you a whole bunch of problems.
Stick to the simple, stick to what you know. Be an expert in PHP and you never have to depend on a framework again. Don't get me started with OOP MVC Frameworks. Interpreted languages for the web were never meant to be OOP. OOP just adds another layer of complexity. Stop being lazy. Use your PHP, and learn how to freakin program!
On the other hand, I can see how making games on a console can be difficult without OOP. But then again, it's apples an oranges. Console games keep their objects in memory until the game exits, or object is destroyed from within game. Think about it... Why do they have a loading bar in front of every level? Now, imagine a web page that has to show you a loading bar every time it loads because it has to create objects from a database. SLLOOOOOOWWWWW central! And once you navigate away from this page, you have to start all over again.
Web pages are applications within themselves. It's like rebuilding your drag racer each time you go to the starting line, only to take it apart at the finish line. WTFridge? Seriously? Hey, super geniuses who think OOP is sooo cool... Keep your damn OOP out of my websites!
Just saying, this is from my 10+ years experience with web development, you know when we used to code pages in HTML, one by one?
OOP is nothing more than a programming paradigm !! but his importance is that hi is THE actual paradigm in use implying that all modern knowledge and best practices in software engineering will be expressed following this style of programming ...
A good example in your case (web development) is the Core J2EE Patterns.
(source: sun.com)
Of course it does. You (and more so your boss) say "rebuilding" like it's a huge chore.
What you mean by "rebuilding" is running the program. Tell your boss that OOP in general is stupid because even in a desktop environment every time somebody runs a piece of software the objects need to be rebuilt so it's not even worth it.
Boss's comment is useless. The .net framework consists of objects and nothing else. A "response" is an object, even in "classic ASP" - why would people have implemented it if that were resource ineffective?
I am building a web application and have been told that using object oriented programming paradigms affects the performance of the application.
I am looking for input and recommendations about design choices that come from moving from One Giant Function to a Object-Oriented Programming Interface.
In order to be more specific: If a Web Application used OOP and created objects that live for a very short time period. Would the performance hit of creating objects on the server justify using a more functional ( I am thinking static functions here ) design.
Wow, big question, but in short (and comment if you want more info) OOP code/practises (ideally well written at that) will give you far more maintainability, testability and joy to code in that OGF coding.
As for the speed arguement, that really is only an issue if you are really trying to squeeze every possible last ounce of CPU out of a server thats going to get hammered. In which case you are problably doing something wrong and need to think about better/more servers or you work for NASA or are doing it for a dare.
I dont know about performance but it definitely makes it easier to maintain.
I am looking for input and
recommendations about design choices
that come from moving from One Giant
Function to a Object-Oriented
Programming Interface.
as David suggested, answering the above will require lot of pages.
Perhaps you should be looking at frameworks. They make some design choices for you.
The most popular way of designing a web app with OOD/OOP is to use the Model-View-Controller pattern. To summarise the 3 main participants:
Model - I'm the stuff in the problem domain that you're manipulating.
View - I'm responsible for drawing and managing what you see in the browser. In web apps, this often means setting up a html template and pushing name-value pairs out into it.
Controller - I'm responsible for handling requests that come in from the web and working out what to do with them and arranging with the other objects to get that work done.
Start with the controller...
Views and Controllers often come in pairs. The controller accepts the HTTP request, works out what needs doing - and it either does it (if the work is trivial) or delegates the work to another object to do. Typically it find the view that's to be used and gives it to the object that's doing the actual work to write output into.
What I've described here corresponds with what you'd expect to find in something like Ruby on Rails.
Making lots of objects that you use once is certainly a concern - but I wouldn't worry about that aspect of performance up front. Proper virtual machines know how to manage short-lived objects. There's plenty of things you can do to speed up a web app - and I would start by sacrificing the benefit of clear organization for a speed up that might not even be the most important optimization...
MVC isn't the only way to go, there are other patterns like Model-View-Presenter and some really unusual approaches like continuation servers (e.g. Seaside) - which reuse the same objects between HTTP requests...
Yes. When doing an OO approach to web app development (using Seaside) I can deliver functionality so much faster that I have sufficient time to think about how to deliver the right amount of performance.
I read a debate in the comments here (current live site, without comments).
Why the debate? A Dataset for me is like a relational database, an Object is a hierarchical-like model. Why do people absolutely want a "pure" Object model, whereas we still deal with relational databases, so why not combine the two?
And if we should, is there any lightweight, comprehensive framework that allows us to do that (not a heavy mammoth, like NHibernate, which has a huge learning curve)?
"Pure objects" are a lot easier to work with, the typed object gives you intellisense and compile-time type checking.
Bare datasets are very cumbersome and annoying to work with - you need to know the column names, there's no type checking possible, so if you mistype a column name, you're out of luck and won't discover the error until runtime (the worst possible scenario).
Typed datasets are a step in the right direction, but the "things" you work with in your .NET code are still tied very closely and tightly to your database implementation - not typically a good thing, since any change in the underlying database might affect your app all the way up to your UI and cause a lot of changes being necessary.
Using an ORM like NHibernate allows you to better abstract and decouple the database (physical storage) layer from your logical business model - only in the simplest of scenarios will those two be an exact 1:1 match, so you'll need some kind of "translation" or mapping between the two anyway.
So all in all - using typed datasets might be okay for small, simple apps, but for a challenging, larger-scale, enterprise-level business app, I would never recommend coupling your business object model so closely and tightly to the database.
Marc
why do people absolutly want "pure" Object model
Because you don't want your application to depend on the database schema
Well, all the reasons you give were the same as the academical reasons that were given for EJB in Java which was a mess in the past. So arent't people falling into another fashionable hype ?
As I read here:
http://blogs.tedneward.com/2006/06/26/The+Vietnam+Of+Computer+Science.aspx
the promise is one thing, the reality is other thing.
Where is the proof upon the claims ?
Scientifically, Complexity is tight to the Concept of Entropy, you cannot reduce the inherent complexity of things, you can just move it somewhere else, so for me there is something fundamentally irational.
Ted Newards is highly controversial because it seems to me that everybody is herding like in the old EJB days: nobody dared to say EJB suck until Rod Johnson gets out with Hibernate.
Now it seems nobody cares to say ORM frameworks like Hibernate, Entity Framework, etc. are too complex, because there isn't yet another Rod Johnson II maybe :)
You pretend that adding a new layer solves the problem, it's not always the case even theorcially, like adding more team members when a project becomes a mess because adding more programmers also mean add to coordination and communication problem.
And in practice, what it seems, is that the layers that should be independant at least from the GUI viewpoint, aren't really. I see many people struggle to do simple stuff in the GUI when they use an ORM.