将 else-if 代码更改为更简洁的代码

Question

I have following else-if code and I am really getting annoying with a size of the lines needed for it, so I was thinking if there is some more appropriate way to do it which will be more cleaner and more faster?

if (dialogResult == 0) {
            System.out.println("Yes option to try again!");
            if (level.equals(lp.LEVEL1.getLevelName())) {
                System.out.println(lp.LEVEL1.getLevelName());
                level = lp.LEVEL2.getLevelName(); // set level
                totalBall = lp.LEVEL2.getBallCount();
                numberOfExplodes = lp.LEVEL2.getBallExplosion();

            } else if (level.equals(lp.LEVEL2.getLevelName())) {
                System.out.println(lp.LEVEL2.getLevelName());
                level = lp.LEVEL3.getLevelName(); // set level
                totalBall = lp.LEVEL3.getBallCount();
                numberOfExplodes = lp.LEVEL3.getBallExplosion();

            } else if (level.equals(lp.LEVEL3.getLevelName())) {
                System.out.println(lp.LEVEL3.getLevelName());
                level = lp.LEVEL4.getLevelName(); // set level
                totalBall = lp.LEVEL4.getBallCount();
                numberOfExplodes = lp.LEVEL4.getBallExplosion();

            } else if (level.equals(lp.LEVEL4.getLevelName())) {
                System.out.println(lp.LEVEL4.getLevelName());
                level = lp.LEVEL5.getLevelName(); // set level
                totalBall = lp.LEVEL5.getBallCount();
                numberOfExplodes = lp.LEVEL5.getBallExplosion();

            } else if (level.equals(lp.LEVEL5.getLevelName())) {
                System.out.println(lp.LEVEL5.getLevelName());
                level = lp.LEVEL6.getLevelName(); // set level
                totalBall = lp.LEVEL6.getBallCount();
                numberOfExplodes = lp.LEVEL6.getBallExplosion();

            } else if (level.equals(lp.LEVEL6.getLevelName())) {
                System.out.println(lp.LEVEL6.getLevelName());
                level = lp.LEVEL7.getLevelName(); // set level
                totalBall = lp.LEVEL7.getBallCount();
                numberOfExplodes = lp.LEVEL7.getBallExplosion();

            } else if (level.equals(lp.LEVEL7.getLevelName())) {
                System.out.println(lp.LEVEL7.getLevelName());
                level = lp.LEVEL8.getLevelName(); // set level
                totalBall = lp.LEVEL8.getBallCount();
                numberOfExplodes = lp.LEVEL8.getBallExplosion();

            } else if (level.equals(lp.LEVEL8.getLevelName())) {
                System.out.println(lp.LEVEL8.getLevelName());
                level = lp.LEVEL9.getLevelName(); // set level
                totalBall = lp.LEVEL9.getBallCount();
                numberOfExplodes = lp.LEVEL9.getBallExplosion();

            }
            ...

I was thinking switch could go fine here, but I would like to hear other options as well.

UPDATE: This is my class: lp is of class Balls which is enum and has 3 params in it's constructor:

public enum BallCount {

    LEVEL1(5,1,"Level 1"),
    LEVEL2(10,2,"Level 2"),
    LEVEL3(15,4,"Level 3");

Answer 1

Make LEVEL1, LEVEL2, LEVEL3.... or `lp' to implement following method:

/**
 * Gets Level enum from name.
 */    
public static Level getLevelFromName(String);

/**
 * Gets next level. 
 * Each level may either keeps reference to the next level or 
 * using enum cardinal number can get the next number.
 */
public Level getNextLevel();

Then your if-then gets reduced to following one/two liner with no conditions.

Level nextLevel = Level.getLevelFromName(level).getNextLevel();
level = lp.LEVEL6.getLevelName(); // set level
totalBall = lp.LEVEL6.getBallCount();
numberOfExplodes = lp.LEVEL6.getBallExplosion();

Answer 2

You can replace the conditional with polymorphism. Basically, it means that you move the implementation in the if blocks into the same function on each of the objects. Then, just invoke the function, and the right code will run.

You can take a look at https://sourcemaking.com/refactoring/replace-conditional-with-polymorphism for a more thorough explanation.