createHashMapObject

2.14

Hover & click on the images for description

Description

Description:

Create a HashMap with an Object-Oriented Programming behaviour.
Inside a object, Methods (if they are called correctly, either by engine or via call - Syntax 3) will have the objects instance inside the _self variable.
The Destructor ("#delete" method) will be executed when the last reference to the objects variable gets deleted. (Except when the mission is ended and all variables are deleted at once)

Inheritance: HashMap objects support a simple form of Inheritance.
It behaves similar to the merge command with overwriteExisting enabled. Sub-class methods and properties with same name, overwrite their Base-class values.
Constructor/Destructor/Clone methods will be merged together and executed in sequence.
Flags entry will use overwrite behaviour.

Groups:

HashMap

Syntax

Syntax:

createHashMapObject [classDefinition, constructorArguments]

Parameters:

classDefinition: HashMap or Array of Arrays, format [name, value]: name can be anything like any other HashMap, but it must be a String for it to be used like an OOP object method (see call - Syntax 3).
Some special values, starting with #, are reserved and expect a specific value type (they are all optional):

• "#create": Code - this is the hashmap object's constructor
• "#clone": Code - this is code happening when cloning is done on this hashmap object
• "#delete": Code - this is the hashmap object's destructor. It will always be executed inside missionNamespace.
• "#str": Code - code that is used to evaluate what is displayed when the str function is called on the object - must return String
• "#flags": Array of Strings - case-insensitive flags regarding this hashmap object
  • "noCopy": forbids copying, +_hashMapObject will throw an error
  • "sealed": prevents from adding and removing any keys - key values can still be edited
  • "unscheduled": all methods (including #clone and #create) will be executed in unscheduled environment
• "#base": Array or HashMap - declaration of base class for inheritance
• "#type": Any - can be used to give a object a "type name", on inheritance types will be merged into an Array

Note that all entries beginning with # are reserved, the engine might use these internally without their use being documented.

constructorArguments: Anything - (Optional, default Nothing) passed as _this argument to the "#create" method.

Return Value:

HashMap

Examples

Example 1:

private _declaration = [ ["#flags", ["sealed"]], ["#create", { hint "Hello!" }], ["#clone", { hint "We were copied!" }], ["#delete", { hint "Goodbye" }], ["#str", { "My HashMap Object" }], ["Method", { hint "Method has been called" }] ]; private _hashMapObject = createHashMapObject [_declaration]; // hints "Hello!" _hashMapObject call ["Method"]; // hints "Method has been called" hint str _hashMapObject; // hints "My HashMap Object" private _shallowCopy = _hashMapObject; // no hint private _deepCopy = +_hashMapObject; // hints "We were copied!" // at the end of the scope, _hashMapObject is deleted and hints "Goodbye"

Example 2:

Inheritance constructor/destructor/copy orderings:

private _animalDeclaration = [ ["#type", "IAnimal"], ["#create", { systemChat "Animal Init" }], ["#clone", { systemChat "Animal Copied" }], ["#delete", { systemChat "Animal Bye" }] ]; private _pigDeclaration = [ ["#base", _animalDeclaration], ["#type", "Pig"], ["#create", { systemChat "Pig Init" }], ["#clone", { systemChat "Pig Copied" }], ["#delete", { systemChat "Pig Bye" }] ]; private _smolPigDeclaration = [ ["#base", _pigDeclaration], ["#type", "SmolPig"], ["#create", { systemChat "SmolPig Init" }], ["#clone", { systemChat "Smol Copied" }], ["#delete", { systemChat "Smol Bye" }] ]; private _smolPigInstance = createHashMapObject [_smolPigDeclaration]; // prints "Animal Init", "Pig Init", "SmolPig Init" private _copy = +_smolPigInstance; // prints "Animal Copied", "Pig Copied", "SmolPig Copied" _copy = nil; // prints "SmolPig Bye", "Pig Bye", "Animal Bye"

Example 3:

Inheritance type checking:

private _animalDeclaration = [ ["#type", "IAnimal"], ["FurType", { "None" }] // default implementation ]; private _pigDeclaration = [ ["#base", _animalDeclaration], ["#type", "Pig"], ["FurType", { "Bristles" }] // override the base class method ]; private _catDeclaration = [ ["#base", _animalDeclaration], ["#type", "Cat"], ["FurType", { "Hair" }] // override the base class method ]; private _instance = createHashMapObject [selectRandom [_pigDeclaration, _catDeclaration]]; if ("IAnimal" in (_instance get "#type")) then // check if a object instance is or inherits from a specific type { _instance call ["FurType"]; // now that we know it implements IAnimal, we know that "FurType" method will be present };

Example 4:

Destructor:

private _temporaryVehicle = [ ["#create", { params ["_vehicleType", "_vehiclePos", "_lifetimeSeconds"]; // handle constructor arguments private _newVehicle = _vehicleType createVehicle _vehiclePos; _self set ["MyVehicle", _newVehicle]; // Store the vehicle inside the object for later // because _self is passed as parameter, it will be referenced by the spawned script until it ends. [_lifetimeSeconds, _self] spawn { params ["_lifetimeSeconds", "_self"]; sleep _lifetimeSeconds; }; }], ["#delete", { deleteVehicle (_self get "MyVehicle"); // delete the vehicle when we go away }], ["MyVehicle", objNull] // placeholder, this is not needed ]; // create a temporary RoadCone, at player position, that will delete itself after 5 seconds. createHashMapObject [_temporaryVehicle, ["RoadCone_F", getPos player, 5]];

Additional Information

See also:

call createHashMap

Notes

Report bugs on the Feedback Tracker and/or discuss them on the Arma Discord or on the Forums.
Only post proven facts here! Add Note