Most efficient null avoidance

[Frank Cisco]

What's the most efficient way to avoid nulls when getting objects from array

eg.

String eg = array.get("test");
if(eg==null){eg="";} //without this then null pointer gets thrown...

if(!eg.equals("EXAMPLE")){ // ...here
//do something
}

or maybe...

String eg = array.get("test")==null?"":array.get("test"); //neater but 2
lookups with this though

or maybe...

String eg=null;
if((eg=array.get("test"))!=null){
//do stuff
}


I take it the 3rd one is the most efficient?

 

[Arne Vajhøj]

What's the most efficient way to avoid nulls when getting objects from array

eg.

String eg = array.get("test");
if(eg==null){eg="";} //without this then null pointer gets thrown...

if(!eg.equals("EXAMPLE")){ // ...here
//do something
}

or maybe...

String eg = array.get("test")==null?"":array.get("test"); //neater but 2
lookups with this though

or maybe...

String eg=null;
if((eg=array.get("test"))!=null){
//do stuff
}

I take it the 3rd one is the most efficient?

I would go for:

String eg = array.get("test");
if(eg != null) {
//do stuff
}

because I believe it most clearly expresses the logic.

BTW, I would never never never name a variable of something
that is not an array as "array" (I would probably not name
an array as "array", but that would be a minor issue).

Arne

 

[Frank Cisco]

I would go for:

String eg = array.get("test");
if(eg != null) {
//do stuff
}

because I believe it most clearly expresses the logic.

BTW, I would never never never name a variable of something
that is not an array as "array" (I would probably not name
an array as "array", but that would be a minor issue).

Arne

cheers, bit daft now i think of it

thats the one

 

[Lew]

Ensure your array is fully populated.

Seriously.

That is almost always the correct and best answer.

 

[Daniel Pitts]

What's the most efficient way to avoid nulls when getting objects from array

eg.

String eg = array.get("test");
if(eg==null){eg="";} //without this then null pointer gets thrown...

if(!eg.equals("EXAMPLE")){ // ...here
//do something
}

or maybe...

String eg = array.get("test")==null?"":array.get("test"); //neater but 2
lookups with this though

or maybe...

String eg=null;
if((eg=array.get("test"))!=null){
//do stuff
}


I take it the 3rd one is the most efficient?

What about being the most correct? Shouldn't that be the first
consideration? After that, all of the above are practically the same in
speed.

Note that "" and null have different semantic meanings, and should not
generally be mixed and matched unless you have good justification.

How about this:
final String eg = array.get("test");
// NPE is avoided because string literal is never null:
if ("EXAMPLE".equals(eg)) {
// do something.
}

Or,
if (myString != null && myString.equals(otherString)) {
}