difference between factory and prototype design pattern

P.S. A real prototype has to implement this interface and implement the clone() function to return an copy of itself. In this diagram the ConcreteBuilder has multiple  functions  that create each part of the product (but I just put one, buildPart(), because I’m lazy). Unless your singleton takes a huge amount of memory, you should use this way. I personally avoid  using it since it makes the code more difficult to unit test and creates a tight coupling. Moreover, it makes the code less predictable. Creational patterns are design patterns that deal with object initialization and overcome the limitations of constructors. The idea of this pattern is to simulate named optional arguments. If you need to remember one thing it’s to use single instances instead of singletons. Or you can continue reading, as the theoretical difference is done, and real programmer likes code So, let’s see each design patterns with code snippets:. Here is a very simple way to create a singleton in Java using the pre-instantiated approach. Let’s look at the problem this pattern solves. The Gang of Four in their book “Design Patterns: Elements of Reusable Object-Oriented Software” described five of them: 1. Bank.java. All the properties of a person can only be modified by classes in the same package. Since this book was released (in 1994), many creational patterns have been invented: 1. other type of factories (like the static one), 2. pool pattern, 3. lazy initialization, 4. dependency injection, 5. ser… In my diagram, there is just one method, buildPart(). This pattern is meant to build objects by copy instead of constructors. finally I found clear and understandable explanation for those patterns. A possible way is to manage single instances with a factory and Dependency Injection (it will be the subject of a future post). 2. In singleton JAVA implementation class, the method getInstance() is not static. Advantage of Prototype Pattern. Most of the time the pattern is used for this use case. there is a good article on dzone about the, There is also this very good answer on stackexchange about the, the prototype is a an interface that defines a function clone(). Oops, I’ve just made the correction. Imagine you have a trading application that makes hundreds of calls per seconds and it only needs to have the stock prices from the last minutes. If I quote the java API: “Every Java application has a single instance of class Runtime that allows the application to interface with the environment in which the application is running. For example, if you read the following code, can you easily understand what the parameters are? Another use of this pattern was popularized by Joshua Bloch, a Java developper who led the construction of many Java APIs. when a system should be independent of how its products are created, composed, and represented, when the classes to instantiate are specified at run-time, for example, by dynamic loading, to avoid building a class hierarchy of factories that parallels the class hierarchy of products. pre-initialized (which means it is instantiated before someone call getInstance()), lazy-initialized (which means it is instantiated during the first call of getInstance()), When you need only one resource (a database connection, a socket connection …), To avoid multiple instances of a stateless class to avoid memory waste. I guess this class has to be unique because it represents the global state (environment variables) of the process. I should have used getter and setter but I wanted to have a short example. get data from another server (with sockets, web services or whatever). Use a single instance instead of a singleton, Design Pattern: Liskov’s Substitution Principle (LSP), Design pattern: singleton, prototype and builder, Machine Learning: Andrew NG’s course from coursera. In a way, this pattern is very close to the State pattern. In my example, if I don’t add public setters in the Person class, a Person instance is immutable since no class outside the package can modify its attributes. If you have an instance that is mutable and you want to give it to another part of the code, for security reasons you might want to give a duplicate instead of the real instance because this instance can be modified by the client code and have an impact on other parts of the code that use it. In order to deal with this simple need, we’ve just created 5 constructors which a lot of code. Factory method is used to delegate the responsibility of choosing which implementation or subclass you want to use like Car interface can be implemented by SportsCar and EconomicalCar and based upon budget factory will return appropriate object. This type of design pattern comes under creational pattern as this … The Abstract Factory Pattern can be implemented using the Factory Method Pattern, Prototype Pattern or the Singleton Pattern. Related Patterns. Using an ArrayList, I can clone it and get a new ArrayList that contains the same data as the original one: content of the set [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] Sometimes, object creation is heavyweight and requires a lot of resources, creating a new instance will impact the performance. there is no similarity between these two patterns prototype is used when object construction is expensive. You delegate the creation of PersonBusiness to a factory and this factory also takes care of the creation of DatabaseConnection: It chooses which kind of connection to create (for example using a property file that specify the type of connection). Each class needs to log and this log class is often unique (because the logs are written in the same file). I have also discussed what is the difference between the factory pattern and abstract factory design pattern. This is not a good example since the PersonBusiness could have a single instance since it has no state. You don’t need the builder interface nor multiple builder implementations nor a director for this problem. of a particular interface -- say, IFruit.With the Abstract Factory pattern, you produce implementations of a particular Factory interface -- e.g., IFruitFactory. a private constructor (Singleton()) : it prevents anyone to instantiate a Singleton with a constructor. But this time, it’s a loose coupling, which means instead of using a MysqlDatabaseConnection, you can easily use a MockDatabaseConnection for testing only the PersonBusiness class. Both the Abstract Factory and Factory design pattern are creational design pattern and use to decouple clients from creating objects they need, But there is a significant difference between Factory and Abstract Factory design pattern, Factory design pattern produces implementation of Products e.g. In my opinion, these patterns are less important than factories. Ok, I 'think' now after looking at the GOF "Applicability" section, I see some major differences. • the construction process must allow different representations for the object that’s constructed. Since most applications are based on frameworks, the implementation of the single instance is easier than from scratch (assuming you know how to use the framework). 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