Java Switch Statement

Question

I have a problem using switch statement when I tried to deal with a special situation. For example, I have 3 cases: A, B, C.

• for A, I want to do statement_1 and st

Answer 1

If a case has more than 2-3 statements it's bette(from point of view of readability and clean code) to extract them as separate methods:

switch (variable){
    case A: handleCaseA(); break;
    case B: handleCaseB(); break;
    default: handleDefaultCase(); break;
}

Answer 2

Here u must use if statement in this way because in switch there are normally default value also.

    if (letter == 'A' || letter == 'B') { System.out.println("Statement 3 ");}

switch (letter) {
            case 'A':
                System.out.println("Statement 1 ");
                break;

            case 'B':
                System.out.println("Statement 2 ");
                break;

            case 'C':
                System.out.println();
                break;
            default:
                System.out.println("You entered wrong value");
}       

Answer 3

I often find introducing enums adds clarity. Here I imagine each enum is an issue which can be resolved through a number of processes:

enum Issue {
  A {
    void handleIt () {
      statement_1();
      statement_3();
    }
  },
  B {
    void handleIt () {
      statement_2();
      statement_3();
    }
  },
  C {
    void handleIt () {
      // Do nothing.
    }
  },
  D {
    void handleIt () {
      A.handleIt();
      B.handleIt();
    }
  };

  abstract void handleIt();
}

Note here that you get the added benefit of being able to handle certain issues using the solutions of other issues (see my D enum).

Answer 4

i would recommend to define exactly what staments should be executed:

switch (variable){
    case A: 
        statement_1();
        statement_3();
        break;
    case B: 
        statement_2();
        statement_3();
        break;
}

for Update-3:

create methods for those 10 lines:

public void statement_1() {
    //your 10 lines of code
}

if you're always executing statement_3, except for case C you can go with if/else-blocks as you wrote them.

but in my honest opinion: define EXACTLY what has to be done in which case if you have a small amount of cases. it is easier to read for others

Answer 5

You can do this:

switch (variable){
  case A:  do statement_1; do statement_3; break;
  case B:  do statement_2; do statement_3; break;    
}

Answer 6

Why not nest the switch into the if statement? there is no-repeat code this way.

if(!C){
    statement_3;
    switch(variable){
    case A:
        statement_1;
        break;
    case B: 
        statement_2;
        break;
}

or make use of both the if-statement and the switch?

if(!C){
    statement_3;
}
switch(variable){
case A:
    statement_1;
    break;
case B: 
    statement_2;
    break;