Builder Pattern

Builder Pattern

The builder pattern is an object creation software design pattern. The intention is to abstract steps of construction of objects so that different implementations of these steps can construct different representations of objects. Often, the builder pattern is used to build products in accordance with the composite pattern.

The intent of the Builder pattern is to separate the construction of a complex object from its representation. By doing so, the same construction process can create different representations.

Builder Pattern

Builder
Abstract interface for creating objects (product).

Concrete Builder
Provides implementation for Builder. It is an object able to construct other objects. Constructs and assembles parts to build the objects.

Builder Pattern: Example:

  • Builder Pattern: Create class Pizza:
package com.builder;

public class Pizza {
	private String dough = "";
	private String sauce = "";
	private String topping = "";

	public void setDough(String dough) {
		this.dough = dough;
	}

	public void setSauce(String sauce) {
		this.sauce = sauce;
	}

	public void setTopping(String topping) {
		this.topping = topping;
	}
}

 

  • Builder Pattern: Create abstract class PizzaBuilder:
package com.builder;

public abstract class PizzaBuilder {
	protected Pizza pizza;

	public Pizza getPizza() {
		return pizza;
	}

	public void createNewPizzaProduct() {
		pizza = new Pizza();
	}

	public abstract void buildDough();

	public abstract void buildSauce();

	public abstract void buildTopping();
}

 

  • Builder Pattern: Create class HawaiianPizzaBuilder
package com.builder;

public class HawaiianPizzaBuilder extends PizzaBuilder {
	public void buildDough() {
		pizza.setDough("cross");
	}

	public void buildSauce() {
		pizza.setSauce("mild");
	}

	public void buildTopping() {
		pizza.setTopping("ham+pineapple");
	}
}

 

  • Builder Pattern: Create class SpicyPizzaBuilder
package com.builder;

public class SpicyPizzaBuilder extends PizzaBuilder {
	public void buildDough() {
		pizza.setDough("pan baked");
	}

	public void buildSauce() {
		pizza.setSauce("hot");
	}

	public void buildTopping() {
		pizza.setTopping("pepperoni+salami");
	}
}

 

  • Builder Pattern: Create class Waiter
package com.builder;

public class Waiter {
	private PizzaBuilder pizzaBuilder;

	public void setPizzaBuilder(PizzaBuilder pb) {
		pizzaBuilder = pb;
	}

	public Pizza getPizza() {
		return pizzaBuilder.getPizza();
	}

	public void constructPizza() {
		pizzaBuilder.createNewPizzaProduct();
		pizzaBuilder.buildDough();
		pizzaBuilder.buildSauce();
		pizzaBuilder.buildTopping();
	}
}

 

  • Builder Pattern: Create class BuilderExample
package com.builder;

public class BuilderExample {
	public static void main(String[] args) {
		Waiter waiter = new Waiter();
		PizzaBuilder hawaiianPizzaBuilder = new HawaiianPizzaBuilder();
		PizzaBuilder spicyPizzaBuilder = new SpicyPizzaBuilder();
		waiter.setPizzaBuilder(hawaiianPizzaBuilder);
		waiter.constructPizza();
		Pizza pizza = waiter.getPizza();
	}
}

 

  • That’s it. Below is list of all design patterns link:

Creational Patterns:

Structural Patterns:

Behavioral Patterns:

Builder Pattern

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