Java条件语句（检查条件中的第一个条件）

Question

if((x == 5) || (x == 2)) {  
    [huge block of code that happens]  
    if(x == 5)  
        five();  
    if(x == 2)  
        two();  
}

So I'm checking for either 5 or 2. And there is a huge block of code that happens after either 5 or 2. The problem is that then I want to do different things depending on whether it is 5 or 2. I didn't want to have separate conditionals for 5 or 2 for the huge block of code (duplicating it would be unwieldy). I also didn't like the way I did it above because x is actually really long.

Is there a way to say something like:

if((x == 5) || (x == 2)) {  
    [huge block of code that happens]  
    if(first conditional was true)  
        five();  
    if(second conditional was true)  
        two();  
}  

I can always do it the way I did above. Just curious if such an option exists.

Answer 1

If the conditionals are big, ugly, and much less nice than x == 5 , then just store the results in a boolean :

boolean xWasFive = x == 5;
boolean xWasTwo = !xWasFive && x == 2;
if (xWasFive || xWasTwo) {
  ...
  if (xWasFive) doA;
  else if (xWasTwo) doB;
}

Answer 2

One way I can think of is basically to "alias" the longer boolean expressions in the if condition:

boolean expr1, expr2;

if (expr1 = (x == 5) | expr2 = (x == 2)) {  
    // huge block of code that happens
    if (expr1) five();
    if (expr2) two();
}

I used non short-circuiting operator to ensure expr2 gets assigned.

Answer 3

Only thing I can think of would be to set a flag for both options. Sort of like this:

boolean wasFive = x == 5;
boolean wasTwo = x == 2;

if(wasFive || wasTwo) {  
   [huge block of code that happens]  
   if(wasFive)  
       five();  
   if(wasTwo)  
       two();  
 } 

Answer 4

Maybe something like this:

final boolean firstCondition = (x == 5);
final boolean secondCondition = (x == 2);

if (firstCondition || secondCondition) {
    // code
    if(firstCondition) {
        // code 
    }
    else if (secondCondition) {
        // code
    }
}