When using the Stream API, call chains should be simplified as much as possible. Not only does it make the code easier to read, it
also avoid creating unnecessary temporary objects.
This rule raises an issue when one of the following substitution is possible:
| Original |
Preferred |
stream.filter(predicate).findFirst().isPresent()
|
stream.anyMatch(predicate)
|
stream.filter(predicate).findAny().isPresent()
|
stream.anyMatch(predicate)
|
!stream.anyMatch(predicate)
|
stream.noneMatch(predicate)
|
!stream.anyMatch(x -> !(...))
|
stream.allMatch(...)
|
stream.map(mapper).anyMatch(Boolean::booleanValue)
|
stream.anyMatch(predicate)
|
Noncompliant code example
boolean hasRed = widgets.stream().filter(w -> w.getColor() == RED).findFirst().isPresent(); // Noncompliant
Compliant solution
boolean hasRed = widgets.stream().anyMatch(w -> w.getColor() == RED);
