> For the complete documentation index, see [llms.txt](https://aaronice.gitbook.io/object-oriented-design/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://aaronice.gitbook.io/object-oriented-design/ood-case-studies/shape-factory.md).

# Shape Factory

### Description

Factory is a design pattern in common usage. Implement a`ShapeFactory`that can generate correct shape.

You can assume that we have only tree different shapes:*Triangle*,*Square\_and\_Rectangle*.

### Example

Example 1:

```
Input:
ShapeFactory sf = new ShapeFactory();
Shape shape = sf.getShape("Square");
shape.draw();
Output:
  ----
 |    |
 |    |
  ----
```

Example 2:

```
Input:
ShapeFactory sf = new ShapeFactory();
shape = sf.getShape("Triangle");
shape.draw();
Output:
   /\
  /  \
 /____\
```

Example 3:

```
Input:
ShapeFactory sf = new ShapeFactory();
shape = sf.getShape("Rectangle");
shape.draw();
Output:
  ----
 |    |
  ----
```

## Solution

直接根据对应类型输出对应形状即可

```java
/**
* This reference program is provided by @jiuzhang.com
* Copyright is reserved. Please indicate the source for forwarding
*/

/**
 * Your object will be instantiated and called as such:
 * ShapeFactory sf = new ShapeFactory();
 * Shape shape = sf.getShape(shapeType);
 * shape.draw();
 */
interface Shape {
    void draw();
}

class Rectangle implements Shape {
    // Write your code here
    @Override
    public void draw() {
        System.out.println(" ---- ");
        System.out.println("|    |");
        System.out.println(" ---- ");
   }
}

class Square implements Shape {
    // Write your code here
   @Override
   public void draw() {
        System.out.println(" ---- ");
        System.out.println("|    |");
        System.out.println("|    |");
        System.out.println(" ---- ");
   }
}

class Triangle implements Shape {
    // Write your code here
   @Override
   public void draw() {
        System.out.println("  /\\");
        System.out.println(" /  \\");
        System.out.println("/____\\");
   }
}

public class ShapeFactory {
    /**
     * @param shapeType a string
     * @return Get object of type Shape
     */
    public Shape getShape(String shapeType) {
        // Write your code here
        if (shapeType == null) {
            return null;
        }        
        if (shapeType.equalsIgnoreCase("Triangle")) {
            return new Triangle();
        } else if(shapeType.equalsIgnoreCase("Rectangle")) {
            return new Rectangle();         
        } else if(shapeType.equalsIgnoreCase("Square")) {
            return new Square();
        }
        return null;
    }
}
```


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