I have done some programming with MVC but never really thought about class diagrams within them, but thinking about it I dont understand how a class diagram would work with one.
Would you just create a class diagram of each model,
Also, when I have used codenigter, i return query results from the model rather than a whole object, so would there even be any attributes?
Thanks
Would you just create a class diagram of each model
Anything that helps with clarity. I find its easiest to create a new diagram for each model.
Also, when I have used codenigter, i return query results from the model rather than a whole object, so would there even be any attributes?
Im not sure what you mean here? Why do you think your "results" are not objects? In pure OO everything (Integers, Strings etc) are objects too.
Related
While working with Unity, I realized that separating Model and View would make my code more readable and straightforward. Constructing the whole model, all I had to do is just create some UI and bind it to Model.
But I still don't understand what 'Controller' is, and why does it exist. I don't think I had trouble when I directly bound View to Model, not through Controller.
So the question is if we can bind View to Model directly, why do we need Controller? What's the benefit of having Controller between Model and View?
At the highest level the Controller is the link between the View (displaying the UI/UX) and the Model (creating and managing your database and its tables).
True, it is possible to write code without any Controller usage but your Views will quickly get very cluttered and each file will be full of logic that is much more nicely stored somewhere else hint hint.
The Controller (and Model and some other places such as helpers) is thus the perfect place to sort out all the back-end code so that all you need to do is send a single field or object to your View to display.
An example is somewhat painful because by its nature the Controller is where you go to sort out your code as things get more complicated but this is a great article to get you on the right track! HTH
https://www.toptal.com/unity-unity3d/unity-with-mvc-how-to-level-up-your-game-development
I don't have years of experience, but in my understanding controllers provide a bridge across view and models. While view contain the pretty part and models contain useful parts the controller do the calls of functions passing values from database to view or inputs to model. That provide a way to avoid lots of injection like class A calling class B, calling class C, etc.
You can put rule business in controllers or in view, but thats not the expected in MVC architecture. The first important thing (for me) in software programming is readability, whats MVC provide.
if you've interest, search for other architectures like MVVM, to compare then.
I'm new to Backbone.js and in my recent project I need a custom validation mechanism for models. I see two ways I could do that.
Extending the Backbone.Model.prototype
_.extend(Backbone.Model.prototype, {
...
});
Creating custom model that inherit from Backbone model
MyApp.Model = Backbone.Model.extend({ ... });
I quite unsure which one is a good approach in this case. I'm aware that overriding prototype is not good for native objects but will that applies to backbone model prototype as well? What kind of problems I'll face if I go with the first approach?
You are supposed to use the second approach, that's the whole point of Backbone.Model.extend({}).
It already does your first approach + other near tricks to actually setup a proper inheritance chain (_.extend is only doing a copy of the object properties, you can look up the difference in code for Backbone's extend() and Underscore's _.extend, they are very large and not very interesting. Just extending the .prototype isn't enough for 'real' inheritance).
When I first read your question, I misunderstood and thought you were asking whether to extend from your own Model Class or directly extend from Backbone Extend. It's not your question, so I apologize for the first answer, and just to keep a summary here: you can use both approach. Most large websites I saw or worked on first extend from Backbone.Model to create a generic MyApp.Model (which is why I got confused, that's usually the name they give to it :)), which is meant to REPLACE the Backbone.Model. Then for each model (for instance User, Product, Comment, whatever..), they'll extend from this MyApp.Model and not from Backbone.Model. This way, they can modify some global Backbone behavior (for all their Models) without changing Backbone's code.
_.extend(Backbone.Model.prototype, {...mystuff...}) would add your property/ies to every Backbone.Model, and objects based on it. You might have meant to do the opposite, _.extend({...mystuff...}, Backbone.Model) which won't change Backbone itself.
If you look at the annotated Backbone source you'll see lines like
_.extend(Collection.prototype, Events, { ... Collection functions ...} )
This adds the Events object contents to every Collection, along with some other collection functions. Similarly, every Model has Events:
_.extend(Model.prototype, Events, { ... Model functions ...})
This seems to be a common pattern of making "classes" in Javascript:
function MyClass(args) {
//Do stuff
}
MyClass.prototype = {....}
It's even used in the Firefox source code.
I am brand new to Magento and the documentation, primarily the phpDocs, are difficult to navigate. For example,
$attributeSet = Mage::getModel('eav/entity_attribute_set')->load($id);
In the php doc for Class Mage_Eav_Model_Entity_Attribute_Set there is no mention of the method getAttributeSetName() either in inherited methods or otherwise and yet this works.
$attributeSet = Mage::getModel('eav/entity_attribute_set')->load($id);
echo $attributeSet->getAttributeSetName();
So I suppose I have several questions.
Can someone explain to me why the documentation is this way?
Where I can find the mysterious getAttributeSetName() method in the phpDocs?
My theory is that there is some inheritance or a design pattern implementation going on that I'm not understanding, maybe someone can shed some light on this for me.
If you really want to fry your brain, take a look at the source code for Mage_Eav_Model_Entity_Attribute_Set and follow the inheritance chain all the way back. You won't find a getAttributeSetName method defined anywhere.
All Magento objects that inherit from Varien_Object can have arbitrary data members set on them. Try this.
$attributeSet = Mage::getModel('eav/entity_attribute_set')->load($id);
$attributeSet->setFooBazBar('Value');
var_dump($attributeSet->getFooBazBar());
var_dump($attributeSet->getData('foo_baz_bar'));
var_dump($attributeSet->setData('foo_baz_bar','New Value'));
var_dump($attributeSet->getFooBazBar());
You can also get all the data members by using
var_dump($attributeSet->getData());
but be careful dumping these, because if there's a data object that has a circular reference and you're not using something like xDebug, then PHP will have a fit trying to display the object.
Magento stores data properties in a special _data array property. You can get/set values in this array with getData and setData. Magento also has implemented magic getting and setter methods, so when you say something like
$object->getFooBazBar();
The method getFooBazBar is transformed into the data property foo_baz_bar. and then getData is called using this property. It's a little tricky to get your head around, but once you get it you'll start to see how much time you can save using this pattern.
One side effect of this is, of course, it's impossible to infer what data properties any object might have by looking at it's class file, so there's no phpDocs for these methods.
I've looked through the other questions and am still struggling so if anybody could take the time to look at this, it would be much appreciated :).
I currently have my app working fine but I've been reading and have decided it doesn't fit the MVC design pattern. I am still learning lots about design and would like to edit it so that it is more sound.
I think I know what should go in to my model class, and I think that it should be instantiated in the app delegate. My questions are: why in that location? Is lazy instantiation the best/correct way to do this? And finally, once initiated, do I use a property to access the class or do you use special methods?
Sorry for the overload; I am also trying to get my reputation up enough to vote on other questions! :)
It's really hard to answer a general question like this, since there are so many ways one could implement any particular project. In general, I don't think that instantiating a model class in your app delegate is necessarily the way to go. Since a controller class mediates between the model and the view, it's often better to instantiate your model in a controller class -- for instance, I have a program that keeps track of the plants in my garden, and my controller class is a subclass of NSArrayController. It seems to make sense to create new plant objects in the controller and then just add them to its arrangedObjects. I try to have as few connections (via properties or ivars) between classes as I can, the thought being that each class should take care of its own business as much as possible. Often, you don't need to have a reference to the class, because you are calling class methods to create new objects, and then those objects can access any instance methods of that class without any explicit reference to the class.
I asked this question to get some opinions on the subject of glue code.
For example, imagine you have a class (pseudocode):
class MyClass
int attribute a
string attribute b
And to represent that data model, you have BOTH a slider and a text box to represent a, and a text box and say... the window label to represent b.
Obviously, when one of these view objects is changed, you want to update the others. However, updating the entire view is obviously inefficient.
method onSomethingHappened(uiObject)
model.appropriateAttribute = uiObject.value
The question is, what is your opinion on what to do next? Should the model object implement a callback that notifies a listener when the value has been changed, allowing one to write glue code like:
method modelChangedCallback(model, attribute)
uiObject1.value = model.a
uiObject2.value = model.a
Where you might examine what the attribute that changed is, and respond accordingly? This is the model in Objective-C and Cocoa on Mac, for the most part.
OR, would you rather have the responsibility lie completely in the glue code?
method onSomethingHappened(uiObject)
model.appropriateAttribute = uiObject.value
self.updateForAttribute("appropriateAttribute")
Both of these approaches can get pretty hairy (as is the problem with glue code) when your project gets large. Maybe there are other approaches. What do you think?
Thanks for any input!
For me I think it comes down to where the behavior is needed. In the situation you describe, the fact that you are binding multiple controls to a property is what is driving the requirement, so it doesn't make sense to add code to the model to support that.
In a web-based model I would probably put the logic in the web page since that can be done rather cheaply using Javascript. If I don't have that luxury (i.e. I'm dealing with a "dumb" view), then it would probably make sense to do it in the controller, or model glue code. If this sort of thing becomes common enough, I may go as far as creating some form of generic helper to reduce the amount of boiler-plate code I have to deal with.