Switch Statement in Java netbeans

I have different fields using the same parameters i.e. same grading scale. I want to use switch statement to return grades for different fields using the same scale. Something like this. I thought that there was something like this: switch (attend, job, initiative) { that would combine the three variables.

int attend = 5;
int job = 5;
int initiative = 5;

switch (attend) {
    case  1:
        getattendo = 5;
        break;
    case  2:
        getattendo = 4;
        break;
    case  3:
        getattendo = 3;
        break;
    case  4:
        getattendo = 2;
    case  5:
        getattendo = 1;
        break;
    default:
        getattendo = 0; // null
}

Your help is appreciated.

fmk

Something like switch(a,b,c) is not possible.

If all values are the same, just use one of the valueslandmaybe verify that all values are the same).

However, there are workarounds if you want to switch-case with multiple numbers:

mathematical solution

For example, you could use prime numbers for this. As you only want to switch numbers, this is possible as long as there is a prime number higher than the highest expected value(for attend, prime and job).

Instead of switch(attend, job, initiative), you use switch((attend*prime+job)*prime+initiative) and instead of case (exampleAttend, exampleJob, exampleInitiative):, you use case ((exampleAttend*prime+exampleJob)*prime+exampleInitiative):

Note that prime must be the same in the switch and case statements.

Note that you should test if any of the input numbers is higher than the prime. This would logically lead to the default case but it could lead to collissions.

You may also want to make sure that the prime to the forth power is lower than the max value of the data type or there may be overflows.

On the other side, this method should be more performant than the second.

simple string concadation

Another option is to work with strings. As the string representation of a number is unique (to the number) and it does not contain some characters (like spaces), you can concadate those numbers and use such a character to seperate them.

Instead of switch(attend, job, initiative), you use switch(attend+" "+job+" "+initiative) and instead of case (exampleAttend,exampleJob,exampleInitiative):, you use case (exampleAttend+" "+exampleJob+" "+exampleInitiative):.

This is obviously easier and fail-safer than the first method involving prime numbers but there should be a performance impact as concadating strings is slower than multiplying ints.

Another possibility is to use enums. Look at the other answer by @Hassam Abdelillah
if you want to know how this works. If you like the enum approach, feel free to upvote the other answer.

Enum works well with switch cases. So, you can define an enum that represents your range of value of it is a finite and reasonable range of values :

public enum OPTIONS {
	OPTION1(5, 5, 5),
	OPTION2(5, 2, 4),
	OPTION3(1, 2, 3),
	OPTION4(4, 4, 1);

	private final int attend;
    private final int jobs;
    private final int initiative;

	Directive(int attend, int jobs, int initiative) {
		this.attend = attend;
		this.jobs = jobs;
		this.initiative = initiative;
	}

    // ... optional setters & getters
}

Given your create OPTION Enum, you can use a switch to handle the different cases :

switch (OPTION) {
    case  OPTION1:
        getattendo = 5;
        break;
    case  OPTION2:
        getattendo = 4;
        break;
    case  OPTION3:
        getattendo = 3;
        break;
    case  OPTION4:
        getattendo = 2;
        break;
    default:
        getattendo = 0; // null
        break;
}

Note: Your switch is legitimate only if you have a finite number of condition. Otherwise, use a method to calculate your result.

A trick you use utilizes the unary or operation for checking binary digit presence.

This will help get you started on switching according to various conditions.

This is similar to how file permissions work in Linux.

public class ScoreCombinator {
    public static final int ATTEND     = 1; // binary: 001
    public static final int JOB        = 2; // binary: 010
    public static final int INITIATIVE = 4; // binary: 100

    public static void main(String[] args) {
        evaluate(ATTEND | INITIATIVE);       // Attend and Initiative
        evaluate(INITIATIVE | ATTEND | JOB); // Attend, Job, and Initiative
    }

    private static void evaluate(int value) {
        switch (value) {
            case ATTEND: {
                System.out.println("Attend");
                break;
            }
            case ATTEND | JOB: {
                System.out.println("Attend and Job");
                break;
            }
            case ATTEND | JOB | INITIATIVE: {
                System.out.println("Attend, Job, and Initiative");
                break;
            }
            case ATTEND | INITIATIVE: {
                System.out.println("Attend and Initiative");
                break;
            }
            case JOB: {
                System.out.println("Job");
                break;
            }
            case JOB | INITIATIVE: {
                System.out.println("Job and Initiative");
                break;
            }
            case INITIATIVE: {
                System.out.println("Initiative");
                break;
            }
        }
    }
}