Calisthenics

"Calisthenics are exercises consisting of a variety of gross motor movements; often rhythmical and generally without equipment or apparatus."

object calisthenics

but Why bother?

"Code is read more than it is written"

"You need to write code that minimizes the time it would take someone else to understand it - even if that someone else is you."

class Board {
    public String board() {
        StringBuilder buf = new StringBuilder();

        // 0
        for (int i = 0; i < 10; i++) {
            // 1
            for (int j = 0; j < 10; j++) {
                // 2
                buf.append(data[i][j]);
            }
            buf.append("\n");
        }

        return buf.toString();
    }
}

class Board {
    public String board() {
        StringBuilder buf = new StringBuilder();

        collectRows(buf);

        return buf.toString();
    }

    private void collectRows(StringBuilder buf) {
        for (int i = 0; i < 10; i++) {
            collectRow(buf, i);
        }
    }

    private void collectRow(StringBuilder buf, int row) {
        for (int i = 0; i < 10; i++) {
            buf.append(data[row][i]);
        }

        buf.append("\n");
    }
}

Benefits of rule #1

public void login(String username, String password) {
    if (userRepository.isValid(username, password)) {
        redirect("homepage");
    } else {
        addFlash("error", "Bad credentials");

        redirect("login");
    }
}

public void login(String username, String password) {
    if (userRepository.isValid(username, password)) {
        return redirect("homepage");
    }

    addFlash("error", "Bad credentials");

    return redirect("login");
}

Benefits of rule #2

Benefits of rule #3

class Location {
    public Piece current;
}

class Piece {
    public String representation;
}

class Board {
    public String boardRepresentation() {
        StringBuilder buf = new StringBuilder();

        for (Location loc : squares()) {
            buf.append(loc.current.representation.substring(0, 1));
        }

        return buf.toString();
    }
}

class Location {
    private Piece current;

    public void addTo(StringBuilder buf) {
        current.addTo(buf);
    }
}
class Piece {
    private String representation;

    public String character() {
        return representation.substring(0, 1);
    }

    public void addTo(StringBuilder buf) {
        buf.append(character());
    }
}
class Board {
    public String boardRepresentation() {
        StringBuilder buf = new StringBuilder();

        for (Location location : squares()) {
            location.addTo(buf);
        }

        return buf.toString();
    }
}

benefits of rule #4

Why abbreviate?

Benefits of rule #5

Benefits of rule #6

benefits of rule #7

benefits of rule #9