I had expected,
Node.__proto__===Function.prototype
But this is not true.
What is Node.__proto__, or HTMLElement.__proto__?
Thanks,
Eric J.
In JS even primary data types are Objects. This is why you can do for example var.toString or arr.length. They have some basic methods attached to them.
For example:
Node.__proto__ has: __defineGetter__, __defineSetter__, constructor, toString() and so on.
Related
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.
We have following code structure in our code
namedParamJdbcTemplate.query(buildMyQuery(request),new MapSqlParameterSource(),myresultSetExtractor);
and
namedParamJdbcTemplate.query(buildMyQuery(request),new BeanPropertySqlParameterSource(mybean),myresultSetExtractor);
How can I expect these method calls without using isA matcher?
Assume that I am passing mybean and myresultSetExtractor in request for the methods in which above code lies.
you can do it this way
Easymock.expect(namedParamJdbcTemplateMock.query(EasyMock.anyObject(String.class),EasyMock.anyObject(Map.class),EasyMock.anyObject(ResultSetExtractor.class))).andReturn(...);
likewise you can do mocking for other Methods as well.
hope this helps!
good luck!
If you can't use PowerMock to tell the constructors to return mock instances, then you'll have to use some form of Matcher.
isA is a good one.
As is anyObject which is suggested in another answer.
If I were you though, I'd be using Captures. A capture is an object that holds the value you provided to a method so that you can later perform assertions on the captured values and check they have the state you wanted. So you could write something like this:
Capture<MapSqlParameterSource> captureMyInput = new Capture<MapSqlParameterSource>();
//I'm not entirely sure of the types you're using, but the important one is the capture method
Easymock.expect(namedParamJdbcTemplateMock.query(
EasyMock.anyObject(Query.class), EasyMock.capture(captureMyInput), EasyMock.eq(myresultSetExtractor.class))).andReturn(...);
MapSqlParameterSource caughtValue = captureMyInput.getValue();
//Then perform your assertions on the state of your caught value.
There are lots of examples floating around for how captures work, but this blog post is a decent example.
Whilst I'm crawling through the OData Spec's URI syntax looking for an answer, I thought it might be worth asking in case nothing turned up.
If I have an entity: "base", and an entity which inherits from base: "Derived" I end up with an Odata query which can retrieve all instances of base:
blah.svc/bases()
but what query can I use to return just those instances of Derived? I've tried variuos forms of:
blah.svc/bases()?$filter=isof(Derived)
but to no avail.
Unfortunately, I'm struggling to find examples of this on the web, most of the stuff out there just talks about how you can't have navigation properties on derived entites (which isn't even true anymore!!)
Thanks in advance.
you can do the following: blah.svc/bases/Model.Derived - Model.Derived is the full name (namespace+name) of the derived type in the model.
Hope this helps.
Thanks
Pratik
I want mybatis to call a factory method to create an object instead of a constructor. So that for null valued attributes i can return a NULL object(which has overridden behavior to handle all the edge cases) instead of actual object. Can i achieve that with mapper.xml?
Define your own ObjectFactory
http://www.mybatis.org/core/configuration.html#objectFactory
To answer your specific question, there is no way to specify a factory method directly (and only) in the mapper.xml file itself, as far as I know. However, there are two options in MyBatis to do what you want:
As stated in Bhaskar's answer you can use an ObjectFactory.
In theory, you can also define a TypeHandler, but I was unable to get this to work in my recent testing.
If you would like to see a working example of how to use a MyBatis ObjectFactory to implement a Null object, see koan19 of my MyBatis koans: https://github.com/midpeter444/mybatis-koans. (Look in the completed-koans/koan19 directory for the solution I came up with.)
What is the best way of adding a new object in the entity framework. The designer adds all these create methods, but to me it makes more sense to call new on an object. The generated CreateCustomer method e.g. could be called like this:
Customer c = context.CreateCustomer(System.Guid.NewGuid(), "Name"));
context.AddToCustomer(c);
where to me it would make more sense to do:
Customer c = new Customer {
Id = System.Guid.NewGuid(),
Name = "Name"
};
context.AddToCustomer(c);
The latter is much more explicit since the properties that are being set at construction are named. I assume that the designer adds the create methods on purpose. Why should I use those?
As Andrew says (up-voted), it's quite acceptable to use regular constructors. As for why the "Create" methods exist, I believe the intention is to make explicit which properties are required. If you use such methods, you can be assured that you have not forgotten to set any property which will throw an exception when you SaveChanges. However, the code generator for the Entity Framework doesn't quite get this right; it includes server-generated auto increment properties, as well. These are technically "required", but you don't need to specify them.
You can absolutely use the second, more natural way. I'm not even sure of why the first way exists at all.
I guess it has to do with many things. It looks like factory method to me, therefore allowing one point of extension. 2ndly having all this in your constructor is not really best practice, especially when doing a lot of stuff at initialisation. Yes, your question seems reasonable, i even agree with it, however, in terms of object design, it is more practical as they did it.
Regards,
Marius C. (c_marius#msn.com)