kemitix-checkstyle-ruleset/builder/src/main/resources/rules/CyclomaticComplexity.md

Restricts the cyclomatic complexity of a method to 5. The cyclomatic complexity is a measure of the number of decision points in a method.

A method with no branches has a complexity of 1. For each if, while, do, for, ?:, catch, switch, case, && and || the complexity goes up by 1.

Valid:

void isValid(int a, int b, int c) {
    // 1
    if (a > b) { // +1 = 2
        switch (c) { // +1 = 3
            case 1: // +1 = 4
                break;
            case 2: // +1 = 5
                break;
        }
    }
}

Invalid:

void isInvalid(int a, int b, int c) {
    // 1
    if (a > b) { // +1 = 2
        switch (c) { // +1 = 3
            case 1: // +1 = 4
                break;
            case 2: // +1 = 5
                break;
            case 3: // +1 = 6
                break;
        }
    }
}