Law of Demeter

Reports Law of Demeter violations.

The Law of Demeter is not really a law, but specifies a style guideline: never call a method on an object received from another call. The code that follows this guideline is easier to maintain, adapt, and refactor, has less coupling between methods, less duplication, and better information hiding. On the other hand, you may need to write many wrapper methods to meet this guideline.

Example:

boolean pay(Customer c, Invoice invoice) {
  int dollars = c.getWallet().contents; // violation
  if (dollars >= invoice.getAmount()) {
    Wallet w = c.getWallet();
    w.subtract(invoice.getAmount()); // violation
    return true;
  }
  return false;
}

The above example might be better implemented as a method payInvoice(Invoice invoice) in Customer.

Use the Ignore calls to library methods and access to library fields option to ignore Law of Demeter violations that can't be fixed without changing a library.

Inspection options

Option	Type	Default
Ignore calls to library methods and access to library fields	Checkbox	true

Inspection Details
Available in:	IntelliJ IDEA 2023.3, Qodana for JVM 2023.3
Plugin:	Java, 233.SNAPSHOT

Last modified: 13 July 2023