createHashMapObject: Difference between revisions

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(Inheritance)
(More examples and description)
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|descr= Create a [[HashMap]] with an {{Link|https://en.wikipedia.org/wiki/Object-oriented_programming|Object-Oriented Programming}} behaviour.<br>
|descr= Create a [[HashMap]] with an {{Link|https://en.wikipedia.org/wiki/Object-oriented_programming|Object-Oriented Programming}} behaviour.<br>
Inside a object, Methods (if they are called correctly, either by engine or via {{Link|call#Syntax 3}}) will have the objects instance inside the "_self" variable.<br>
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)<br>
<br>
<br>
Inheritance: HashMap objects support a simple form of Inheritance.<br>
Inheritance: HashMap objects support a simple form of Inheritance.<br>
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* {{hl|"#create"}}: [[Code]] - this is the hashmap object's constructor
* {{hl|"#create"}}: [[Code]] - this is the hashmap object's constructor
* {{hl|"#clone"}}: [[Code]] - this is code happening when cloning is done on this hashmap object
* {{hl|"#clone"}}: [[Code]] - this is code happening when cloning is done on this hashmap object
* {{hl|"#delete"}}: [[Code]] - this is the hashmap object's destructor
* {{hl|"#delete"}}: [[Code]] - this is the hashmap object's destructor. It will always be executed inside [[missionNamespace]].
* {{hl|"#str"}}: [[Code]] - code that is used to evaluate what is displayed when - '''must''' return [[String]]
* {{hl|"#str"}}: [[Code]] - code that is used to evaluate what is displayed when - '''must''' return [[String]]
* {{hl|"#flags"}}: [[Array]] of [[String]]s - case-''in''sensitive flags regarding this hashmap object
* {{hl|"#flags"}}: [[Array]] of [[String]]s - case-''in''sensitive flags regarding this hashmap object
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_instance call ["FurType"]; // Now that we know it implements IAnimal, we know that "FurType" method will be present
_instance call ["FurType"]; // Now that we know it implements IAnimal, we know that "FurType" method will be present
};
};
</sqf>
|x3= Destructor: <sqf>
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
[_lifetimeSeconds, _self] spawn {params ["_lifetimeSeconds", "_self"]; Sleep _lifetimeSeconds; } // Because _self is passed as parameter, it will be referenced by the spawned script until it ends.
}],
["#delete", {
deleteVehicle (_self get "MyVehicle"); // Delete the vehicle when we go away
}],
["MyVehicle", objNull] // Placeholder, this is not needed
];
createHashMapObject [_temporaryVehicle, ["RoadCone_F", getPos player, 5]]; // Create a temporary RoadCone, at player position, that will delete itself after 5 seconds.
</sqf>
</sqf>


|seealso= [[call]] [[createHashMap]]
|seealso= [[call]] [[createHashMap]]
}}
}}

Revision as of 13:51, 11 May 2023

Hover & click on the images for description
Only available in Development branch(es) until its release with Arma 3 patch v2.14.

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: Array of Arrays in format [name, value] OR HashMap.
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 - 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(Optional, default: Nothing): Any - Passed as _this argument to "#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" }] ]; _smolPigInstance = createHashMapObject [_smolPigDeclaration]; // Prints "Animal Init", "Pig Init", "SmolPig Init" _copy = +_smolPigInstance; // Prints "Animal Copied", "Pig Copied", "SmolPig Copied" _copy = nil; // Prints "SmolPig Bye", "Pig Bye", "Animal Bye"
Example 3:
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 [_lifetimeSeconds, _self] spawn {params ["_lifetimeSeconds", "_self"]; Sleep _lifetimeSeconds; } // Because _self is passed as parameter, it will be referenced by the spawned script until it ends. }], ["#delete", { deleteVehicle (_self get "MyVehicle"); // Delete the vehicle when we go away }], ["MyVehicle", objNull] // Placeholder, this is not needed ]; createHashMapObject [_temporaryVehicle, ["RoadCone_F", getPos player, 5]]; // Create a temporary RoadCone, at player position, that will delete itself after 5 seconds.

Additional Information

See also:
call createHashMap

Notes

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