trikitrok

Wrap class.

How to do it:

1. Identify the change point.

2. Create a class that accepts the class we are going to wrap as a constructor argument.

   • If we have trouble creating the original class in a test harness, we might have to use Extract Interface on the wrapped class so that we can instantiate the wrapper.

3. Create a method on the wrapper class with tests, that implements the new behaviour.

trikitrok

Sprout class.

How to do it:

1. Identify the change point and determine the sprouted class interface.

   • Pass to the sprouted class’s constructor any source method’s local variables it needs as parameters.

   • Determine whether the sprouted class’ method will need to return values to the source method.

trikitrok

Wrap method.

Version 1 (when clients will only use the composed behaviour).

How to do it:

1. Identify the change point.

2. Extract a method with the body of the current method.

trikitrok

Sprout method.

How to do it:

1. Identify the change point and determine the sprouted method signature (input/output).

   • Pass to the sprouted method any source method’s local variables it needs as parameters.

   • Determine whether the sprouted method will need to return values to any variable in the source method.

trikitrok

<?php

interface Customer {
    public function getEarnedDiscount(): float;

    public function addToOrdersHistory(Order $order): void;
}

// Null Customer's implementation
class NotFoundCustomer implements Customer {

trikitrok

public interface Customer
{
    double GetEarnedDiscount();

    void AddToOrdersHistory(Order order);
}

// Null Customer's implementation
public class NotFoundCustomer : Customer
{

trikitrok

public interface Customer {
    double getEarnedDiscount();

    void addToOrdersHistory(Order order);
}

// Null Customer's implementation
public class NotFoundCustomer implements Customer {
    private final double DEFAULT_DISCOUNT = 1.0;

trikitrok

public class Coordinates {
    public int x;
    public int y;

    public Coordinates(int x, int y) {
        this.x = x;
        this.y = y;
    }
}

trikitrok

public class PageSEO {
  Page calculate(Page current, Search search) {
    // ...
  }
}

trikitrok

public interface IndexationCalculator {
  Page update(Page current, Search search);
}

public interface CanonicalCalculator {
  Page update(Page current, Search search);
}

public class Page {
  public bool isIndexed;