Maxi Contieri

Posted on Apr 12, 2021 • Edited on Apr 9, 2022 • Originally published at maximilianocontieri.com

Code Smell 67 - Middle Man

#webdev #codenewbie #tutorial #oop

Let's break Demeter's Law.

Problems

Unnecessary Indirection
Empty Classes
Readability

Solutions

Remove Middle man.

Sample Code

Wrong

	public class Client {
	Address address;
	public ZipCode zipCode() {
	return address.zipCode();
	}
	}

	public class Address {
	private ZipCode zipCode;

	public ZipCode zipCode() {
	return new ZipCode('CA90210');
	}
	}

	public class Application {
	ZipCode zipCode = client.zipCode();
	}

view raw middleman.java hosted with ❤ by GitHub

Right

	public class Client {
	public ZipCode zipCode() {
	// Can also store it
	return new ZipCode(’CA90210’);
	}
	}

	public class Application {
	ZipCode zipCode = client.address().zipCode();
	}

view raw nowhereman.java hosted with ❤ by GitHub

Detection

Same as its opposite smell, We can detect this small using parsing trees.

Conclusion

This is exactly the opposite to Message Chain. We make explicit the message chain.

Relations

Code Smell 08 - Long Chains Of Collaborations

Maxi Contieri ・ Oct 27 '20

#beginners #codenewbie #oop #100daysofcode

More info

%[https://refactoring.guru/smells/middle-man]

%[https://refactoring.com/catalog/removeMiddleMan.html]

%[https://wiki.c2.com/?MiddleMan]

%[https://www.jetbrains.com/help/idea/remove-middleman.html#remove_middleman_example]

%[https://en.wikipedia.org/wiki/Law_of_Demeter]

Credits

Photo by Dan Counsell on Unsplash

Whenever I have to think to understand what the code is doing, I ask myself if I can refactor the code to make that understanding more immediately apparent.

Martin Fowler