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73 lines
2.5 KiB
73 lines
2.5 KiB
/** |
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* Singleton is an auxiliary class, meant to be used as a base for others, |
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* that allows for only one instance of it to exist. |
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* To make sure your child class properly works, either don't overload |
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* 'PreBeginPlay' or make sure to call it's parent's version. |
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* Copyright 2019 Anton Tarasenko |
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*------------------------------------------------------------------------------ |
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* This file is part of Acedia. |
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* |
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* Acedia is free software: you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation, version 3 of the License, or |
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* (at your option) any later version. |
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* |
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* Acedia is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License |
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* along with Acedia. If not, see <https://www.gnu.org/licenses/>. |
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*/ |
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class Singleton extends Actor |
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abstract; |
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// Default value of this variable will store one and only existing version\ |
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// of actor of this class. |
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var private Singleton activeInstance; |
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// Setting default value of this variable to 'true' prevents creation of |
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// a singleton, even if no instances of it exist. |
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// Only a default value is ever used. |
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var protected bool blockSpawning; |
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public final static function Singleton GetInstance() |
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{ |
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if (default.activeInstance != none && default.activeInstance.bPendingDelete) |
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return none; |
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return default.activeInstance; |
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} |
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public final static function bool IsSingletonCreationBlocked() |
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{ |
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return default.blockSpawning; |
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} |
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// Make sure only one instance of 'Singleton' exists at any point in time. |
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// If you overload this function in any child class - |
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// first call this version of the method and then check if |
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// you are about to be deleted 'bDeleteMe == true': |
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// ____________________________________________________________________________ |
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// | super.PreBeginPlay(); |
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// | // ^^^ If singleton wasn't already created, - only after that call |
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// | // will instance, returned by 'GetInstance()', be set. |
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// | if (bDeleteMe) |
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// | return; |
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// |___________________________________________________________________________ |
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event PreBeginPlay() |
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{ |
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if (default.blockSpawning || GetInstance() != none) |
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{ |
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Destroy(); |
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} |
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else |
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{ |
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default.activeInstance = self; |
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} |
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} |
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defaultproperties |
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{ |
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blockSpawning = false |
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} |