Defined in List.Def Mixes in with Object
The HasCount mixin provides you with a way to associate the concept of a count to a collection of objects. How you implement the count is up to you.
Remember that if the documentation and the software (especially the definition files) disagree, always trust the software.
The HasCount mixin is a very small mixin used by a large set of classes. All of the list classes inherit from HasCount, for example. You might use the HasCount mixin while creating your own classes, but it's most likely you'll encounter it while using one of the many system-defined classes that inherit from it.
Instantiate: never Subclass: always Call its methods: sometimes
If you are creating a subclass using the HasCount mixin directly, you will need to redefine the Count attribute and implement a Count method. Many implementors of Count add a count field to their subclass definition, and simply define Count to return the contents of the field.
The HasCount mixin has the following methods you might call:
| Method | Description |
|---|---|
| Count | Get the count attribute |
| Empty | Check to see if count is zero |
attribute Count: Unsigned, readOnly, safe, noGetter; // operation Count(): Unsigned call: sometimes Override: always
The HasCount mixin does not define the Count method. If you create your own subclass using it, you'll want to redefine the Count attribute and write your own method.
attribute Empty: Boolean, readOnly; // operation Empty(): Boolean call: sometimes Override: rarely