- Python Design Patterns Tutorial
- Python Design Patterns - Home
- Introduction
- Python Design Patterns - Gist
- Model View Controller Pattern
- Python Design Patterns - Singleton
- Python Design Patterns - Factory
- Python Design Patterns - Builder
- Python Design Patterns - Prototype
- Python Design Patterns - Facade
- Python Design Patterns - Command
- Python Design Patterns - Adapter
- Python Design Patterns - Decorator
- Python Design Patterns - Proxy
- Chain of Responsibility Pattern
- Python Design Patterns - Observer
- Python Design Patterns - State
- Python Design Patterns - Strategy
- Python Design Patterns - Template
- Python Design Patterns - Flyweight
- Abstract Factory
- Object Oriented
- Object Oriented Concepts Implementation
- Python Design Patterns - Iterator
- Dictionaries
- Lists Data Structure
- Python Design Patterns - Sets
- Python Design Patterns - Queues
- Strings & Serialization
- Concurrency in Python
- Python Design Patterns - Anti
- Exception Handling
- Python Design Patterns Resources
- Quick Guide
- Python Design Patterns - Resources
- Discussions
Python Design Patterns - Prototype
Prototype design pattern helps to hide the complexity of the instances created by the class. The concept of the existing object will differ with that of the new object, which is created from scratch.
The newly copied object may have some changes in the properties if required. This approach saves time and resources that go in for the development of a product.
How to implement a prototype pattern?
Let us now see how to implement a prototype pattern.
import copy class Prototype: _type = None _value = None def clone(self): pass def getType(self): return self._type def getValue(self): return self._value class Type1(Prototype): def __init__(self, number): self._type = "Type1" self._value = number def clone(self): return copy.copy(self) class Type2(Prototype): """ Concrete prototype. """ def __init__(self, number): self._type = "Type2" self._value = number def clone(self): return copy.copy(self) class ObjectFactory: """ Manages prototypes. Static factory, that encapsulates prototype initialization and then allows instatiation of the classes from these prototypes. """ __type1Value1 = None __type1Value2 = None __type2Value1 = None __type2Value2 = None @staticmethod def initialize(): ObjectFactory.__type1Value1 = Type1(1) ObjectFactory.__type1Value2 = Type1(2) ObjectFactory.__type2Value1 = Type2(1) ObjectFactory.__type2Value2 = Type2(2) @staticmethod def getType1Value1(): return ObjectFactory.__type1Value1.clone() @staticmethod def getType1Value2(): return ObjectFactory.__type1Value2.clone() @staticmethod def getType2Value1(): return ObjectFactory.__type2Value1.clone() @staticmethod def getType2Value2(): return ObjectFactory.__type2Value2.clone() def main(): ObjectFactory.initialize() instance = ObjectFactory.getType1Value1() print "%s: %s" % (instance.getType(), instance.getValue()) instance = ObjectFactory.getType1Value2() print "%s: %s" % (instance.getType(), instance.getValue()) instance = ObjectFactory.getType2Value1() print "%s: %s" % (instance.getType(), instance.getValue()) instance = ObjectFactory.getType2Value2() print "%s: %s" % (instance.getType(), instance.getValue()) if __name__ == "__main__": main()
Output
The above program will generate the following output −
The output helps in creating new objects with the existing ones and it is clearly visible in the output mentioned above.
Advertisements