Question
Which design pattern would be most appropriate to ensure
that only one instance of a class exists and provides a global point of access to that instance?┬аSolution
The Singleton Pattern is a design pattern used to restrict a class to only one instance, ensuring that the same instance is globally accessible across the application. This pattern is particularly useful in cases like logging, configuration management, or database connections, where multiple instances could lead to resource conflicts or inefficiencies. The Singleton Pattern is typically implemented by making the class constructor private, defining a static method for instance retrieval, and storing the single instance in a static variable. This setup ensures that the instance is created only once and reused throughout the application, conserving resources and maintaining consistency by providing a unified point of interaction. Option A (Factory Pattern) - The Factory Pattern is focused on creating objects based on input parameters without limiting the number of instances, unlike Singleton, which restricts instantiation. Option C (Observer Pattern) - Observer Pattern establishes a dependency between objects, allowing them to notify others of changes, differing from SingletonтАЩs focus on single-instance enforcement. Option D (Strategy Pattern) - Strategy Pattern is used to select algorithms dynamically at runtime, focusing on behavioral variability rather than instance control. Option E (Decorator Pattern) - The Decorator Pattern enhances objects with additional functionalities dynamically, unrelated to the Singleton goal of limiting instance creation.
рдЕрдореЗрд░рд┐рдХрд╛ рдореЗрдВ рдПрдХ рдмрд╛рд░ ............ рд╣реБрдИ ред рджрд┐рдП рдЧрдП рдЙрдкрдпреБрдХреНрдд рд╢рдмреНрдж рд╕реЗ рд░рд┐рдХреНрдд я┐╜...
рдирд┐рдореНрдирд▓рд┐рдЦрд┐рдд рдореЗрдВ рд╕реЗ рдХреМрди-рд╕рд╛ рд╢рдмреНрдж 'рдмрд╛рджрд▓' рдХрд╛ рдкрд░реНрдпрд╛рдпрд╡рд╛рдЪреА рдирд╣реАрдВ рд╣реИ?
' рд╕рд╕реБрд░ ' рдХрд╛ рддрддреНрд╕рдо рд╢рдмреНрдж рд╣реИ __________
рдкрдпреЛрдзрд┐ рдХрд┐рд╕рдХрд╛ рд╕рдорд╛рдирд╛рд░реНрдереА рд╢рдмреНрдж рд╣реИ-
рд╕реВрдЪреА- I рдХреЛ рд╕реВрдЪреА тАУ II рд╕реЗ рд╕реБрдореЗрд▓рд┐рдд рдХреАрдЬрд┐рдП рдФрд░ рд╕реВрдЪрд┐рдпреЛрдВ рдХреЗ рдиреАрдЪреЗ рджрд┐рдП рдЧя┐╜...
рдХрд┐рд╕ рд╡рд┐рдХрд▓реНрдк рдореЗрдВ рддрд╛рд▓рд╡реНрдп рд╡реНрдпрдВрдЬрди рдирд╣реАрдВ рд╣реИред
┬а рднрд╛рд╡рд╡рд╛рдЪреНрдп рдХрд╛ рдЙрджрд╛рд╣рд░рдг рд╣реИ
рдирд┐рдореНрдирд▓рд┐рдЦрд┐рдд рдореЗрдВ рд╕реЗ embodied cost┬а рд╢рдмреНрдж рдХрд╛ рд╡рд┐рддреНрддреАрдп рд╢рдмреНрджрд╛рд╡рд▓реА рдореЗрдВ я┐╜...
'рдЕрдВрдЧреБрд▓реА' рдХрд╛ рддрджреНрднрд╡ рд░реВрдк рдХреМрдирд╕рд╛ рд╣реИ ?
рдирд┐рдореНрдирд▓рд┐рдЦрд┐рдд рдореЗрдВ рд╕реЗ рдХрд┐рд╕ рд╢рдмреНрдж рдореЗрдВ 'рдЖрдк' рдкреНрд░рддреНрдпрдп рдХрд╛ рдпреЛрдЧ рд╣реБрдЖ рд╣реИ ?