I looked up a matterjs rectangle object and noticed an id. Is there is any way to retrieve the rectangle object by that id?
Object Data Example:
id:5
type:body
label:Rectangle Body
parts:Array
plugin:Object
angle:0
vertices:Array
position:Object
Use this:
Matter.Composite.get(composite, id, type);
More information: https://brm.io/matter-js/docs/classes/Composite.html#method_get
Related
I'm trying to understand get_instance_id()
and I came across this line in the documentation:
This ID can be saved in EncodedObjectAsID, and can be used to retrieve
the object instance with #GDScript.instance_from_id.
I can't seem to understand what this statement means exaclty and how to use EncodedObjectAsID, could someone please provide a working example?
The EncodedObjectAsID follows a pattern called Boxing. Boxing is where you put a primitive value, like an int, into an object. This boxed primitive can now be used in an object oriented way. For example, you can pass the boxed int to a function that only takes objects (i.e. it applies Polymorphism):
func only_takes_object(obj: Object)
only_takes_object(123) # Error
var box = EncodedObjectAsID.new()
box.object_id = 123
only_takes_object(box) # Valid
This is how parts of the editor use the EncodedObjectAsId object.
In marshalls.cpp we can see that an encoded Object may be an integer ID or the whole object. When it is flagged as only an integer ID a EncodedObjectAsID object is created. This object is then converted to a Variant.
When adding a stack variable in editor_debugger_inspector.cpp a variant with a type of object is assumed to be and converted to an EncodedObjectAsID to fetch the referenced object's id.
Here's two more links that follow a similar pattern:
array_property_edit.cpp
scene_debugger.cpp
Note that Variant can be implicitly converted to an Object and Object::cast_to() only takes Objects.
This ID can be saved in EncodedObjectAsID, and can be used to retrieve the object instance with #GDScript.instance_from_id.
This sentence should be split into two independent clauses. It should read as
"The instance ID can be saved in an EncodedObjectAsID."
"The instance ID can be used to retrieve the object instance with #GDScript.instance_from_id()."
Note: You should not store an object's id in storage memory. There is no guarantee that an object's id will remain the same after restart.
I am struggling with the concepts of entities and value objects.
I have read about the differences between entities and value objects but I am not able to transfer the knowledge to my example.
I would like to create an aggreagte "retailer"
The retailer has the attributes "id", "name", "adress" (Street, ZIP, Country) and
GPS coordinates (Latitude, Longitude)
My "aggregate root" is the entitiy "retailer".
What is the value object here and what is the attribute of the entitiy?
Is the adress an attribute of entity "retailer" or is "adress" a value object?
Is "GPS" a value object by its own or attributes of value object "adress"?
What is a usefull way to organize this? I added an example how it is organized in my project. What is the value adding the adress to a value object rather adding it as attributes to entitiy "retailer"?
aggregate retailer
What is the value object here and what is the attribute of the entitiy? Is the adress an attribute of entity "retailer" or is "adress" a value object? Is "GPS" a value object by its own or attributes of value object "adress"?
It is both an attribute and a value object: an attribute is from the object oriented point of view; a value object from the DDD point of view: data with behavior, immutable.
GPS should be a value object containing latitude and longitude primitive values.
What is the value adding the adress to a value object rather adding it as attributes to entitiy "retailer"?
The advantage is that a value object encapsulates all its data and behavior, removing responsibilities from it's parent entity. Also, it expresses more intuitively the fact that its properties have a meaning only together (latitude and longitude should be set always together).
I have 2 objects 'data' and 'users' I want to use an object property of data to select a property from the users object. I want to do this
sentToId = users. (data.recipient) . id
What is the correct syntax?
Many thanks!
created a new object
recipientObj = users[data.recipient];
sentToId = recipientObj.id;
I have started using NSIncrementalStore. When you process a fetch request, you first have to process the predicate to get your internal reference objects. Then you convert these to objectID's and then you ask the context to get the corresponding managedObjects. At least that is my interpretation of the available documentation.
let fetchedReferences : [Int] = Array(names.keys) //names represent my backingstore
var fetchedObjectIDs : [NSManagedObjectID] = []
for reference in fetchedReferences
{
fetchedObjectIDs.append(self.newObjectIDForEntity(request.entity, referenceObject: reference))
}
var fetchedObjects : [NSManagedObject] = []
for objectID in fetchedObjectIDs
{
fetchedObjects.append(context.objectWithID(objectID))
}
"newObjectIDForEntity" is also used to obtain permanent objectID's (see obtainPermanentIDsForObjects)
I want to know what "newObjectIDForEntity" does. Does it make a new instance for the same object or does it each time internally create a new object? What I mean is this: if I create a new managed object and then fetch the object, I will have called "newObjectIDForEntity" twice for the same object. Does core data now think there are 1 or 2 objects?
Does it make a new instance for the same object or does it each time internally create a new object?
newObjectIDForEntity:referenceObject: is one of two utility methods for mapping between the store's internal representation of a managed object snapshot and an NSManagedObjectID. It's inverse is referenceObjectForObjectID:. As you might guess from the name, newObjectIDForEntity:referenceObject: returns an object considered to have a retain count of 1. newObjectIDForEntity:referenceObject: calls an internal factory method for generating an NSManagedObjectID that is unique to that reference object in this persistent store. Once that has been done, referenceObjectForObjectID: can look up that NSManagedObjectID and return the reference object it represents.
What I mean is this: if I create a new managed object and then fetch the object, I will have called "newObjectIDForEntity" twice for the same object. Does core data now think there are 1 or 2 objects?
I assume you mean an NSManagedObjectContext that is using your store creates the managed object. You can call newObjectIDForEntity:referenceObject: as many times as you want, the NSManagedObjectID instance may be different, but the data it represents is unchanged. It will know that it points to the same reference object as an earlier call with the same reference data and entity description.
I'm using the YUI2 framework.
I want to be able to get a reference to an object that was created on the page. I don't want to change the existing JS code to store a global handle to it when it is created, if possible.
The page has something like this on it:
<script type="text/javascript">//<![CDATA[
new FirstRate.Reporter("report1").setOptions(
{
inData: "testfunc"
}));
//]]></script>
I don't see any methods in YAHOO.util.Dom specific to finding objects.
How can I get an object reference to FirstRate.Reporter? Is there anything to ennumerate the objects on the page?
Thanks
YUI contains lots of methods for finding objects in the webpage DOM. YAHOO.util.DOM contains methods:
HTMLElement | Array get ( el )
Array getElementsBy ( method , tag , root , apply , o , overrides )
HTMLElement getElementBy ( method , tag , root )
Array getElementsByClassName ( className , tag , root , apply , o , overrides )
and many more. These retrieve objects from the DOM. To find an object in the page with YUI2, you would typically use some combination of the tag type, the class name or the id to query the page using YUI methods to find the object you want. It's easiest to find a specific object in the page if you give it a unique id value and then you can just using YAHOO.util.DOM.get("myObject") to retrieve it (where "myObject" is the id of the HTML element).
If you want to get regular javascript objects, then you have to store references to them yourself in your own javascript variables. YUI doesn't do that for you except when using some UI widgets (which also have DOM elements).
If you want to keep track of the result of this:
new FirstRate.Reporter("report1").setOptions(
{
inData: "testfunc"
})
Then, you have to assign it to a variable or to a property of an object whose scope allows it to last long enough for you to use it.
var theReporter = new FirstRate.Reporter("report1").setOptions(
{
inData: "testfunc"
})
or
myObject.reporter = new FirstRate.Reporter("report1").setOptions(
{
inData: "testfunc"
})
where myObject is some other object you've created and are storing.
JavaScript objects aren't part of DOM. DOM is the Document Object Model, it's about objects in HTML document like divs, forms, inputs etc, the kind of objects Browser displays.
There is no "global enumeration" of objects in JavaScript. There are global variables.
I don't want to change the existing JS code to store a global handle to it
So you don't want to use global variable. But why?
This is the only way to do it, and it's also very simple:
var myGlobalVar = new FirstRate.Reporter("report1").setOptions({inData: "testfunc"}));
Here you'll store reference ("handle" as you say) to your object in global var myGlobalVar, which you can later access in another part of your JavaScript code.