Question

I’m kinda waiting for a ‘no’ answer on this question.

I was interested if you can save a variable at the same time when you checking it in an if-clause.

Let’s say I have this code.

if(foo!=null){   if(foo.getBar()!=null){     Bar bar = foo.getBar();     System.out.println('Success: ' + bar);   } else {     System.out.println('Failure.');   } } else {   System.out.println('Failure.'); } 

I handling now to ‘failure’ -states independently, even if the outcome is the same. I could get them together like this:

if(foo!=null && foo.getBar()!=null){   Bar bar = foo.getBar();   System.out.println('Success: ' + bar); } else {   System.out.println('Failure.'); }  

Much neater code already. if foo is null it will stop there and won’t try foo.getBar (in the if) so I won’t get a NPE. The last thing i would like to enhance, and the main question: Do I really gave to call on foo.getBar() twice? It would be nice to get away from the second identical call if getBar() would be a very heavy operation. So I am wondering if there is somehow possible to do something similiar to this:

if(foo!=null && (Bar bar = foo.getBar())!=null){   Bar bar = foo.getBar();   System.out.println('Success: ' + bar); } else {   System.out.println('Failure.'); } 

I would have to break it up to two different if’s again if I would like to do

Bar bar = foo.getBar(); if (bar!=null) ... 

Answer 1

This is the closest you can get:

Bar bar; if(foo!=null && (bar = foo.getBar())!=null){   System.out.println('Success: ' + bar); } else {   System.out.println('Failiure.'); }