> For the complete documentation index, see [llms.txt](https://heronyang.gitbook.io/clean-up-your-spaghetti/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://heronyang.gitbook.io/clean-up-your-spaghetti/4_stand_on_giants/factory_pattern.md).

# Factory Pattern

## Problem

Who should be responsible for creating objects when there are special considerations, such as complex creation logic, a desire to separate the creation responsibilities for better cohesion, and so forth?

## Solution

Create a Pure Fabrication object called a Factory that handles the creation.

**Shape.java**

```java
public interface Shape {
    void draw();
}
```

**Rectangle.java**

```java
public class Rectangle implements Shape {
   @Override
   public void draw() {
      System.out.println("rectangle draw");
   }
}
```

**Square.java**

```java
public class Square implements Shape {
   @Override
   public void draw() {
      System.out.println("square draw");
   }
}
```

**Circle.java**

```java
public class Circle implements Shape {
   @Override
   public void draw() {
      System.out.println("circle draw");
   }
}
```

**ShapeFactory.java**

```java
public class ShapeFactory {

   public Shape getShape(String shapeType){

      if(shapeType == null) {
         return null;
      }

      if(shapeType.equalsIgnoreCase("CIRCLE")) {
         return new Circle();
      } else if(shapeType.equalsIgnoreCase("RECTANGLE")) {
         return new Rectangle();
      } else if(shapeType.equalsIgnoreCase("SQUARE")) {
         return new Square();
      }

      return null;

   }

}
```

**FactoryPatternDemo.java**

```java
public class FactoryPatternDemo {

   public static void main(String[] args) {

      ShapeFactory shapeFactory = new ShapeFactory();

      Shape shape1 = shapeFactory.getShape("CIRCLE");
      shape1.draw();

      Shape shape2 = shapeFactory.getShape("RECTANGLE");
      shape2.draw();

      Shape shape3 = shapeFactory.getShape("SQUARE");
      shape3.draw();

   }
}
```

*Original example is from* [*tutorialspoint*](http://www.tutorialspoint.com/design_pattern/factory_pattern.htm)

## Think

* Think cohesion and coupling
* Think future reuse and modification


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://heronyang.gitbook.io/clean-up-your-spaghetti/4_stand_on_giants/factory_pattern.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.