Greater than and less than in one statement

Question

I was wondering, do you have a neat way of doing this ?

if(orderBean.getFiles().size() > 0  && orderBean.getFiles().size() < 5)

without declaring a variable that is not needed anywhere else ?

int filesCount = orderBean.getFiles().size();
if(filesCount > 0  && filesCount < 5) {

I mean, in for loop we are "declaring conditions" for the actual iteration, one can declare a variable and then specify the conditions. Here one can't do it, and neither can do something like

if(5 > orderBean.getFiles().size() > 0)

Solution 1

Simple utility method:

public static boolean isBetween(int value, int min, int max)
{
  return((value > min) && (value < max));
}

Solution 2

Several third-party libraries have classes encapsulating the concept of a range, such as Apache commons-lang's Range (and subclasses).

Using classes such as this you could express your constraint similar to:

if (new IntRange(0, 5).contains(orderBean.getFiles().size())
// (though actually Apache's Range is INclusive, so it'd be new Range(1, 4) - meh

with the added bonus that the range object could be defined as a constant value elsewhere in the class.

However, without pulling in other libraries and using their classes, Java's strong syntax means you can't massage the language itself to provide this feature nicely. And (in my own opinion), pulling in a third party library just for this small amount of syntactic sugar isn't worth it.

Solution 3

If getFiles() returns a java.util.Collection, !getFiles().isEmpty() && size<5 can be OK.

On the other hand, unless you encapsulate the container which provides method such as boolean sizeBetween(int min, int max).

Solution 4

This is one ugly way to do this. I would just use a local variable.

EDIT: If size() > 0 as well.

if (orderBean.getFiles().size() + Integer.MIN_VALUE-1 < Integer.MIN_VALUE + 5-1)

Solution 5

If this is really bothering you, why not write your own method isBetween(orderBean.getFiles().size(),0,5)?

Another option is to use isEmpty as it is a tad clearer:

if(!orderBean.getFiles().isEmpty() && orderBean.getFiles().size() < 5)

View more solutions

Comments

[lisak]

This is it :-) I had seen this a long time ago but I haven't used it so that I lost it. But this is exactly what I meant :-) Thank you

[卢声远 Shengyuan Lu]

You mean orderBean.getFiles().size() -5 < 0 ?

[Gareth Davis]

cleaver yes, but this is isn't going to help any body understand your code in six months time

[lisak]

that's right, fortunately I'm not a team player, doing my own business :-)

[Gursel Koca]

not valid for orderBean.getFiles().size() == 0 .. It does not enforce that number of files should be greater than zero

[Nishant]

@Peter Lawrey tell me what I am missing when I say, orderBean.getFiles().size() + Integer.MIN_VALUE-1 < Integer.MIN_VALUE + 5-1 is same as orderBean.getFiles().size() < 5

[lisak]

ok I think I end this, people want it to be a static method. I think it's more convenient that using apache commons IntRange object

[Vishy]

if the size is less than 1 it will underflow to a large positive number and so will not be less than MIN_VALUE+4

[Krzysztof Atłasik]

Question was about Java, not Javascript :).

[qqilihq]

Question is about Java. There are Java-ports of _, but you should at least link to them and give your code in Java syntax.