Question

I have 10 cases in my switch statement. Each of them does the same thing with the other except that the assignments are different. If I have to change 1 line of code (during development) in one case block then I have to change all other 9 cases manually.

Here are the scenarios of each case statements:

1. Each case contains long lines of code with many function calls and assignments.
2. Only variable assignments, function arguments, and if statement conditions vary.
3. There is no pattern/sequence in the assignment of variables and function arguments.
4. Adding helper functions and calling them on each case statements is almost impossible for some reason.

How do I optimize or shorten this?

To illustrate:

final int CONSTANT_A = 0;
final int CONSTANT_B = 1;
...
final int CONSTANT_J = 10;

int varA = 0;
int varB = 1;
...
int varJ = 10;

int anothervarA = 0;
int anothervarB = 1;
...
int anothervarJ = 10;

int action = 0;

switch(something) {
    case 1:
        ... long lines of code here
        // If I have to change the variables below
        // then I have to update all other variables in
        // other cases below
        varA = CONSTANT_J;
        anothervarA = CONSTANT_B;
        ... another long lines of code here
        int ret = someObject.foo(varA);
        ... do something with ret.
        action = 5;
        break;
    case 2:
        ... long lines of code here
        varB = CONSTANT_I;
        anothervarB = CONSTANT_C
        ... another long lines of code here
        int ret = someObject.foo(varA);
        ... do something with ret.
        action = 100;
        break;
    ...
    ...
    case 9:
        ... long lines of code here
        varI = CONSTANT_B;
        anothervarI = CONSTANT_A;
        ... another long lines of code here
        int ret = someObject.foo(varA);
        ... do something with ret.
        action = 100;
        break;
    case 10:
        ... long lines of code here
        varK = CONSTANT_A;
        anothervarJ = CONSTANT_F;
        ... another long lines of code here
        int ret = someObject.foo(varA);
        ... do something with ret.
        action = 4;
        break;
}

Answer 1

Nothing obvious jumps out, except maybe to factor all that code into a set of classes (or an enum), and rely on polymorphism instead of switch to call the right one. So for instance, load your cases into a Map<Integer,Foo> — or even a List<Foo> if it’s not a sparse array — and then replace the switch with myFoos.get(something).whatever();.

As for assigning the variables when you’re done, if they’re member variables you could have the Foos set them directly; if this is always called in a single-threaded environment, you could have foo.whatever() set up state and then have getters. If it’s in a multi-threaded environment, you could have whatever() return back a new object with those getters. Something like:

FooResult result = myFoos().get(something).getResult(whatever, args);
varA = result.getA();
action = result.getAction();
etc