> For the complete documentation index, see [llms.txt](https://hanfak.gitbook.io/workspace/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hanfak.gitbook.io/workspace/general-paradigms/patterns/inheritance-for-resuse.md).

# Inheritance for reuse

* Breaks encapsulation and liskov subsitution
  * See example of Stack inheriting from Vector in Java
* Always refactor to use a wrapper pattern (adpater or decorator)

## How it works

* A subclass inherits from a class to inherit the behaviours that it can use in it's own new behaviour

  ```java
  public class Stack<E> extends Vector<E> {

  public boolean empty() {
    return size() == 0;
  }

  public void push(E item) {
    add(item);
  }

  public E pop() {
    return remove(size()-1);
  }
  }
  ```

## Issues

* Using an instance of the subclass, also has access to the methods of the super class
  * This can lead to the client using the subclass in ways it was not meant to be use, and possibly causing breaking behaviour