I want to customize a standard Fluid Library component in Modelica using OpenModelica.
I want to create a customized version of a new Pump where several equations will be changed.
I inherited Fluid.Machines.BaseClasses.PartialPump as a base model by "extends" keyword. When I tried to change and redefine an equation, it gave an overdetermined system error.
I put redeclare or redifine in front of the equation, and it still gives an error.
What is the best way to create a customised component model without copying everything into a new model?
Thanks
Unfortunately, you cannot change existing code* — you can only add new code.
In your case, you will have to make a copy of Fluid.Machines.BaseClasses.PartialPump and modify the equation in question. However, you don't necessarily need to copy its base class (Modelica.Fluid.Interfaces.PartialTwoPort).
The PartialPump model is quite versatile. If you need different pump curves (pressure, efficiency or power) you can write additional functions based on the base classes in Fluid.Machines.BaseClasses.PumpCharacteristics.
*) One exception to my initial statement is the inheritance of graphical annotations: if you extend a model and add the annotation primitivesVisible=false the graphical annotations (icon) will not be inherited, for example:
model myModel
extends baseModel annotation(IconMap(primitivesVisible=false));
<new icon annotations>
end myModel;
The usage of extends suggests one wants to inherit all the behaviours of the extended class. You can change those behaviours unless they are redeclarable. The best is to create a new class by duplicating the base model and then change the behaviours as you want. Hope this works!
Related
I'm a beginner in MVVM architecture and I'm stuck on an issue in a product app.
The issue: Mapping a Model to an Entity
Let me explain my code structure;
Domain > Respository > order_repo.dart
This order_repo.dart is an abstract class OrderRepo that declares a function getOrders that returns OrderEntity.
Data > Repo Implementation > order_repo_impl.dart
The order_repo_impl.dart contains a class OrderRepoImpl that defines the function getOrders that returns OrderModel that extends OrderEntity.
Domain > Usecase > order_usecase.dart
The order_usecase.dart contains a class that uses OrderUsecase that uses an instance of OrderRepo to call getOrders. Both the getOrders and call functions return OrderEntity.
The problem is that when I call the usecase, I expect it to return OrderEnity but the runtimeType is OrderModel. I tried to parse it as OrderModel but I could not do that because I get this warning, Unnecessary Cast, because at compile time the compiler is also expecting OrderEntity.
One solution I found is to define a Translator, that would convert OrderModel to OrderEntity inside usecase, but I'm confused regarding the right place for its definition, because I cannot use OrderModel inside the Domain layer as per Clean Architecutre to keep Domain independent of other layers and if I define the Tanslator inside Data layer, I still cannot call it in the usecase, because of the same reason.
It is bad practice
The order_repo_impl.dart contains a class OrderRepoImpl that defines the function getOrders that returns OrderModel that extends OrderEntity.
Not always model can extend entity f.e. (Code-Generated Model)
The domain layer should not know about implementation and about the data layer, because Implementation can change but Business logic will not as long as there is no changes in business logic.
I found is to define a Translator that would convert OrderModel to OrderEntity inside usecase
It is good practice
It is good practice to convert it inside implementation of repository. Because, repository is kind of binding between domain and data layers,
Or even, You can create converter class that translate entity to model and vice verca and the instance of the class will be to the constructor of repository implementation.
Why it is better to follow these advices.
Implementation quite often can change but abstraction rarely changes.
Easy to switch from one implementation to another one.
You follow SOLID principles
P.s. I hope I could answer to your question. Whether you have feel free to ask it on comments
I've edited the question to make what I want to obtain clearer.
Here's the original question:
I'm working on a class that inherits from Control which will be used in my View and includes some Dependency Properties.
One of these DPs is an IEnumerable(Of RfidTag) and will be bound to an ObservableCollection(Of RfidTag) inside the VM.
The class RfidTag is defined as public class in the same file where the VM's class resides.
The questions are:
1. is it a good practice to expose a VM-related class to a Control class?
2. is the VM source file a good place for the RfidTag class?
UPDATE 1
In my application logic (I think I could say in my Model) there is an event published throught an Eventaggregator. The event's payload is a List of ModelRfidTag (that is the model class).
My VM subscribes to this event and I made the RfidTag class to wrap my Model class and provides some additional properties related only to the VM.
When the event handler inside the VM is executed, it makes an ObservableCollection(Of RfidTag) bindable from the view.
Then in the View I've a bounch of my control instances like that
<c:RfidTagPresenter
TagPosition="1"
Collection="{Binding RfidTagList, Mode=OneWay}" />
Then in my RfidTagPresenter (the class that inherits from Control) I've a DP of type RfidTag (called RfidTagResult) that returns the object in the OC which has the Position property (property available inside the RfidTag class) equal to the value set by the TagPosition DP.
In this way, the ControlTemplate of the RfidTagPresenter can bind its elements to the desired object.
This is the simplification of what I want to make. In the actual application there are some other DPs on which the RfidTagResult selection is performed
UPDATE 2
After a bit of research, seem that I can solve one problem with an indexed property that return (in the get method) the object from the collection I want to bind.
However a problem still exist: My control need to have a DP of type of RfidTag so that the relative ControlTemplate can bind to the property declared in the RfidTag class.
So: Is it possible (read: a good practice) to have a DP of a type that is a VM related class?
In other words: Can a custom control know about the class type used by the VM?
I will try to go all over your question (if I miss something let me know) but first you should explain the purpose of binding a Collection in a control as a DP.
is it a good practice to expose a VM-related class to a Control class?
RfidTag, I suppose, is a Model. What you are really doing here is binding a Model in your control which go against the MVVM pattern. You should think about the next question... Do you really need all your RfidTag to be shown in the View ? If you need to show a name, an ID... you could just create an IEnumerable<string> as DP (which is correct) and then in your VM instead of an ObservableCollection<RfidTag> you would have an ObservableCollection<string>.
Some simple theory. In MVVM, VM adapts the Model to the View. So your VM should have everything that will be shown in your View.
is the VM source file a good place for the RfidTag class?
RfidTag is a Model so there's no better place for it :)
Good day! I am new to using Unreal Engine 4 and I have a few questions about how exactly blueprints work. From my understanding of it, every blueprint works like a class. By that I mean one blueprint is much like one class in an OOP programming language.
Please educate me as to - if my assumption is correct or wrong. If wrong, then maybe you could help me achieve what I want in a different method/perspective. I am willing to learn and accept suggestions.
If at some point my understanding is correct - that blueprints are actually individual classes - I would really appreciate it if you could (please) guide as to where to go and how to implement a design that I want to create. This is from a programmers perspective (PHP OOP Programming). Forgive the approach, I'm just using PHP to logically express how I want the class to work. Plus, it is the only OOP programming I know atm.
I want to create a class named: Items. class Item {}
This class is going to handle everything item related, thus we will have to give it a lot of properties/variable. (Below is just an example; Again I'm using PHP as an example.)
class Item {
var $id;
var $name;
var $description;
var $type;
var $subType;
var $mesh;
var $materials;
}
3.) I would like to initiate this class by having two variables as its construct arguments. (We will require itemID and itemType). This is because I will use these two variables to retrieve the item's data which is already available in a data table. I will use those data in the table to populate the class properties/variables. (I'm not sure if I said that right. I hope you understood my point anyway.)
class Item {
var $id;
var $name;
var $description;
var $type;
var $subType;
var $mesh;
var $materials;
function _construct($cons_itemID, $cons_itemType) {
/*-- Start getting the item Data here based on what item and type provided. Then, push that data into the class properties/variables. We will use individual methods/functions to fill other properties/variables later. --*/
}
}
4.) Basically with that design I could easily pass on an item ID to the class and then get the item's name, description, mesh, materials and etc using pointers.
Example:
$weapon = new Item('10001','Weapon');
$weaponMesh = $weapon->getMesh();
$armor = new Item('12345','Armor');
$armorName = $armor->getName();
I'm just having a lot of trouble working with blueprint and achieve this method or even something similar to it. I'm not trying to avoid C++, I would love to learn it but I just don't have the time freedom right now.
Few things I have tried to make it work:
Casting / Casting to class (But I couldn't figure out what the target object will be and how was I going to add input arguments into the class that way? There isn't any input there that I could use.)
Spawn Actor (This one is very promising, I need to dig in deeper into this)
Blueprint Macros? Blueprint Interfaces? (I'm just lost.)
For all those who will help or answer. Thank you!
~ Chris
So far as I know, yes, we can assume that each blueprint can be viewed as class. (Moreover, since UE 4.12 (in UE 4.11 that functionality is marked as experimental I think) you can check Compile blueprints under Project settings -> Packaging. That will create native class for each blueprint.)
You can create either Blueprint or C++ class based on Object (UObject in C++). Then you can specify all properties (or variables in UE editor terminology). In BP you have small advantage: you can mark some properties as Visible at spawn (they must be Public and Visible). So when you are creating new instance of that class, you can explicitly pass values to that properties.
And in BP Construct event, that properties are correctly filled, thus you can set another properties values based on given ID and Type.
In C++ class having different arguments than FObjectInitializer is not possible, thus you don't have that values in time when constructor is executed. But it is not so hard to achieve same functionality, you can find example here: https://answers.unrealengine.com/questions/156055/passing-arguments-to-constructors-in-ue4.html.
Something about list of what you had tried:
Spawn actor - derive from actor only if you intend to have that BP in scene. Actors are subjects to game updates and rendering, so having actor only as data container is very wrong.
BP Macro is same as BP Function except function will be called just like function (so executing necesary actions by function call conventions) and macro will replace it's implementation in place, where you are calling that macro. More exhausting explanation here.
If I would implement your code, I'd do it like I said and then I'll have that class as property in some component and that component would be attached to some actor, which would be placed in scene.
I have splitted my application into two main areas.
Part(A)
PartStashContainer(B)
The content of A should be set based on what user wants.
So basically i can have 1..N classes which could be used in Class URI of Part in application model.
I don't know if i should replace the whole Part(A) with new dynamically created Part(C) which has content i want, or i should somehow to modify the existing Part (call setContributionURI, or setObject methods on Part object?).
It does make more sense to me to modify the existing Part, because it is defined in Application model and therefore already describing the location where the content should be.
Possible solutions:
Modify the Part object so it "reload" its content based on new setup (But how? Can setContributionURI or setObject methods help?)
Remove the old Part and add dynamically on same place in Application model the new Part (using EModelService and EPartService).
other solution??
If you want to reuse the Part then do something like:
MPart part = find or inject your part
MyClass myClass = (MyClass)part.getObject();
... call a method of MyClass to change the contents
MyClass is the class you specify for the object in the application model. You should add a method to that to let you change the contents.
Don't try to call setObject, this is really only for use by Eclipse. I don't think setContributionURI would do anything after the part is created (but I am not sure).
If you want to use different classes for the different data then you really should use different Parts.
I have a sample EMF hierarchy like this -
Parent : Shape
Child 1 : Circle
Child 2 : Square
Child 3 : Rect
Now I want to generate my properties view in Eclipse in such a way that . I have a drop down with ShapeType and based on the shape type I want to show the properties of the child element.
Essentially I want to display/edit the child properties based on the 'type' selection in the parent.
Any thoughts how I can achieve this?
You cannot solve this issue easily, as in that case the dropdown needs to change the EMF type of an object, that results in Java class changes. To have such thing working, you have to create a new EObject instance, copy all relevant attributes, and remove the old object (and possibly update the selection).
So, alltogether, I believe, what you want is not possible with basic EMF tooling, however, if you provide a custom model manipulation commands, it should be possible.
Other things, you can try (if possible in your domain):
Move all your data to properties of the parent object, add EValidators to prevent inconsistent states from appearing, and update the default EMF Edit commands to filter out unnecessary editors. Ugly, but may work.
Create custom forms/editors, that manage the object removal/addition during the manually coded editing process.