TL;DR: Refactor and extract functions longer than 5-10 lines of code.

Problems

• Low Cohesion

• High coupling

• Difficult to read

• Low Reuse

Solutions

• Refactor.

• Create small objects dealing with some tasks, and unit-test them.

• Compose methods.

Examples

• Libraries

Sample Code

Wrong

class ChessBoard() {
    init {
        placeOnBoard(whiteTower)
        placeOnBoard(whiteKnight)
        // All other write pieces

        // Empty space to pause definition
        placeOnBoard(blackTower)
        placeOnBoard(blackKnight)
        // All other black pieces
    }

    fun placeOnBoard(piece: Piece) = TODO()
}

Right

class ChessBoard() {
    init {
        placeWhitePieces()
        placeBlackPieces()
    }

    private fun placeWhitePieces() = TODO()
    private fun placeBlackPieces() = TODO()
}

Conclusion

Extract the long method into smaller pieces. Break complex algorithms into parts. This will also allow you to unit-test these parts more easily. Moreover, it improves readability and allows us to focus on the correct level of abstraction in your method.

More info

• Refactoring Guru

Credits

• Code Smell 03 - Functions Are Too Long by Maxi Contieri