Keypad.java

public class Keypad {
    private String passcode;
    private Dispatch police;
    
    public Keypad(String passcode, Dispatch police) {
        this.passcode = passcode;
        this.police = police;
    }
    
    public boolean enterCode(String code) {
        if (code.equals(passcode)) {
            return true;
        } else {
            int softMistakes = 0;
            for (int i = 0; i < code.length(); i++) {
                if (code.charAt(i) != passcode.charAt(i)) {
                    if (hardFault(Integer.parseInt("" + code.charAt(i), Integer.parseInt("" + passcode.charAt(i))) {
                        police.alarm();
                        return false;
                    } else {
                    softMistakes++;
                    }
                }
            }
            if (softMistakes > 1) {
                police.alarm()
            }
            return false;
        }
    }

    private boolean hardFault(int actual, int expected) {
        int actualRow = (actual - 1) / 3;
        int actualColumn = (actual - 1) % 3;
        int expectedRow = (expected - 1) / 3;
        int expectedColumn = (expected - 1) % 3;

        if (actualRow == expectedRow) {
            return actualColumn - 1 != expectedColumn && actualColumn + 1 != expectedColumn;
        }
        if (actualColumn == expectedColumn) {
            return actualRow - 1 != expectedRow && actualRow + 1 != expectedRow;
        }
        return true;
    }
}