Java equivalent of C#'s 'Enumerable.Any'

Question

In C# there is a way of reducing the length of an if-statement by using Enumerable.Any to check if elements in a sequence satisfy a condition (https://msdn.microsoft.com/en-us/library/vstudio/bb534972%28v=vs.100%29.aspx).

For example Instead of:

If ( string.Contains(">") || string.Contains("<") || string.Contains("&") || string.Contains("l") || string.Contains("p") )

We can use

if (new [] { ">", "<", "&", "l", "p"}.Any(w => string.Contains(w)))

Is there an equivalent, if not better, way of doing this in Java?

Answer 1

With Java 8 you can write something like:

if (Stream.of(">", "<", "&", "l", "p").anyMatch(string::contains)) {
  ...
}

Out of curiosity I ran a benchmark to compare this method vs a regex. Code and results below (lower score = faster). Streams perform an order of magnitude better than regex.

Benchmark                                    (s)  Mode  Samples     Score    Error  Units
c.a.p.SO30940682.stream   >aaaaaaaaaaaaaaaaaaaaa  avgt       10    49.942 ±  1.936  ns/op
c.a.p.SO30940682.stream   aaaaaaaaaaaaaaaaaaaaa>  avgt       10    54.263 ±  1.927  ns/op
c.a.p.SO30940682.stream   aaaaaaaaaaaaaaaaaaaaap  avgt       10   131.537 ±  4.908  ns/op
c.a.p.SO30940682.stream   paaaaaaaaaaaaaaaaaaaaa  avgt       10   129.528 ±  7.352  ns/op
c.a.p.SO30940682.regex    >aaaaaaaaaaaaaaaaaaaaa  avgt       10   649.867 ± 27.142  ns/op
c.a.p.SO30940682.regex    aaaaaaaaaaaaaaaaaaaaa>  avgt       10  1047.122 ± 89.230  ns/op
c.a.p.SO30940682.regex    aaaaaaaaaaaaaaaaaaaaap  avgt       10  1029.710 ± 61.055  ns/op
c.a.p.SO30940682.regex    paaaaaaaaaaaaaaaaaaaaa  avgt       10   694.309 ± 32.675  ns/op

Code:

@State(Scope.Benchmark)
@BenchmarkMode(Mode.AverageTime)
public class SO30940682 {

  @Param({">aaaaaaaaaaaaaaaaaaaaa", "aaaaaaaaaaaaaaaaaaaaa>",
          "aaaaaaaaaaaaaaaaaaaaap", "paaaaaaaaaaaaaaaaaaaaa"}) String s;

  @Benchmark public boolean stream() {
    return Stream.of(">", "<", "&", "l", "p").anyMatch(s::contains);
  }

  @Benchmark public boolean regex() {
    return s.matches("^.*?(>|<|&|l|p).*$");
  }
}

Answer 2

With Java 8, this is possible with the anyMatch method:

if (Stream.of(">", "<", "&", "l", "p").anyMatch(w -> string.contains(w))) {

}

Answer 3

If you don't have Java 8, you could just use a regular expression to accomplish your task.

string.matches("^.*?(<|>|p|1|&).*$") should do the trick.

EDIT:

I wonder which solution performs faster. Eventhough JIT can inline all the lambda goodiness, Stream(s) might be slower than using a regular expression. I could be completely wrong and I'd appreciate any insight into this from Java 8 stalwarts.

Answer 4

Looks like org.apache.commons.lang3.StringUtils.containsAny() does what you want.