Is there any possibility to map an existing individual of a class to another class with Protege functions in Jess? The function make-instance creates new instance, while modify-instance allows instance slot updates. But, I would like to use an existing class instance to make it as an instance of another class?
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I want to understand the difference between extends, implements and with. When do I use each keyword?
Extends:
Use extends to create a subclass, and super to refer to the superclass.
Extends is the typical OOP class inheritance. If class a extends class b all properties, variables, functions implemented in class b are also available in class a. Additionally you can override functions etc.
You use extend if you want to create a more specific version of a class. For example the class car could extend the class vehicle. In Dart a class can only extend one class.
Implements:
Every class implicitly defines an interface containing all the instance members of the class and of any interfaces it implements. If you want to create a class A that supports class B’s API without inheriting B’s implementation, class A should implement the B interface.
Implements can be used if you want to create your own implementation of another class or interface. When class a implements class b. All functions defined in class b must be implemented.
When you're implementing another class, you do not inherit code from the class. You only inherit the type. In Dart you can use the implements keyword with multiple classes or interfaces.
With (Mixins):
Mixins are a way of reusing a class’s code in multiple class hierarchies.
With is used to include Mixins. A mixin is a different type of structure, which can only be used with the keyword with.
They are used in Flutter to include common code snippets. A common used Mixin is the SingleTickerProviderStateMixin.
extend can only be used with a single class at the time, BUT... you can easily extend a class which extends another class which extends another class which...! ;)
In fact, most Flutter widgets are already built like that.
In KIF testing framework, in KIF acceptance class, can we create an instance of our controller class or model class to get the functions and views from that specific class? Or is the accessibility label the only way to identify the view? And if the latter is the only option, then how can we get access to our model class in KIF test class?
Yes. You can access anything in your host app.
Also, for your later choice, you can put a weak reference in your view to the model ..
But a notice is that, if you want to modify some static variable or access then, that bundle must be a singleton - Not two copies (one for test, one for app).
I understand the instance variables on an action class are thread-safe since action classes are instantiated per request. But I have this need for extending action classes and I'm concerned about the thread-safety.
Say, for example I have some common attributes and a few methods handling those attributes among several action classes. I prefer to put them in a single action class and make that extend the ActionSupport. And all action classes will then extend the base action class that I just created. My question is, are the instance variables on the base action class thread-safe? Does S2 manage the base action class at all?
Also what makes an action class an action class to be managed by the S2 and instantiated per request? Getting declared in the struts.xml? Extending ActionSupport class?
I think you're a bit confused about how Java works.
If you have a class A and a class B extends A, when you instantiate B there is a B. It's not like there's a single instance of A backing all instances of B. There's no "management of base classes".
Classes declared as actions either via XML, annotations, or convention are instantiated by the Struts action instantiation mechanism. Extending ActionSupport has (almost) nothing to do with it, the only time it might have something to do with it is because ActionSupport implements the Action interface.
Also what makes an action class an action class to be managed by the S2 and instantiated per request? Getting declared in the struts.xml? Extending ActionSupport class?
Getting declared in the struts.xml: yes, is that that turns a Java class into an Action.
And every Action class is thread-safe because it's ThreadLocal, no matter what it extends nor implements. Every request of every user will have its own copy of each Action class.
P.S: The other classes (not declared in struts.xml) are not "(action classes) not managed by S2 and instantiated per request", they're simply NOT Actions.
I have a loop in my controller that does something like this:
for(d in grailsApplication.domainClasses) {
def c = d.getClazz().count()
// construct table containing object instance counts
}
My intent is to use this loop to count the instances of non-leaf domain classes in my database. Is there a way to query the domain class itself to find out if it is abstract or not? I wasn't sure if there were some member functions automatically added by the framework since I am still new to Groovy/Grails. I couldn't find anything that addressed it in the Grails documentation.
Figured it out after a few minutes of poking around the Groovy documentation. The function isAbstract() can be invoked on the domain class to determine whether or not the domain class is a leaf node in the class hierarchy
I have created a separate class (let's call it class2.cs for example) and want to use it as a level, in that when I call it, it will draw everything in one level for me. I'm having trouble getting contentmanager to work in class2. In the given Game1.cs, you can easily just go texture2d= Content.Load<Texture2D>("photo"); but I can't in class2.
I realize I have to create a new Content Manager, but it's constructor requires a game service, in which I'm not sure what I'm suppose to plug in. I currently have: ContentManager content = new ContentManager(); but I need an overload for ContentManager.
Pass Content to the constructor of your second class from the game, or you can create a Globals.cs class with static variables for your ContentManager or spriteBatch or any common resources.