Just want to see by JDK8 lambda how small the program can be, my approach is using a result builder:
IntStream.rangeClosed(0 , 100).forEach(i ->{
StringBuffer bfr= new StringBuffer();
if(i % 3 == 0 )
bfr.append("Fizz");
if(i % 5 == 0 )
bfr.append("Buzz");
if(i % 3 != 0 && i % 5 != 0 )
bfr.append(i);
System.out.println(bfr.toString());
});
Can anyone try to use predicate instead ? I could not think of a way to do this.
Here are three solutions.
Java 8 with Streams:
IntStream.rangeClosed(0, 100).mapToObj(
i -> i % 3 == 0 ?
(i % 5 == 0 ? "FizzBuzz" : "Fizz") :
(i % 5 == 0 ? "Buzz" : i))
.forEach(System.out::println);
Java 8 with Eclipse Collections:
IntInterval.zeroTo(100).collect(
i -> i % 3 == 0 ?
(i % 5 == 0 ? "FizzBuzz" : "Fizz") :
(i % 5 == 0 ? "Buzz" : i))
.each(System.out::println);
Java 8 with Eclipse Collections using Predicates:
Interval.zeroTo(100).collect(
new CaseFunction<Integer, String>(Object::toString)
.addCase(i -> i % 15 == 0, e -> "FizzBuzz")
.addCase(i -> i % 3 == 0, e -> "Fizz")
.addCase(i -> i % 5 == 0, e -> "Buzz"))
.each(System.out::println);
Update:
As of the Eclipse Collections 8.0 release, the functional interfaces in Eclipse Collections now extend the equivalent functional interfaces in Java 8. This means that CaseFunction
can now be used as a java.util.function.Function
, which means it will work with Stream.map(Function)
. The following example uses CaseFunction
with a Stream<Integer>
:
IntStream.rangeClosed(0, 100).boxed().map(
new CaseFunction<Integer, String>(Object::toString)
.addCase(i -> i % 15 == 0, e -> "FizzBuzz")
.addCase(i -> i % 3 == 0, e -> "Fizz")
.addCase(i -> i % 5 == 0, e -> "Buzz"))
.forEach(System.out::println);
Update:
As of the Eclipse Collections 8.1 release, there is now support for primitive case functions. The code above can now be written as follows, removing the call to boxed
. IntCaseFunction
implements IntToObjectFunction
which extends java.util.function.IntFunction
.
IntStream.rangeClosed(0, 100).mapToObj(
new IntCaseFunction<>(Integer::toString)
.addCase(i -> i % 15 == 0, e -> "FizzBuzz")
.addCase(i -> i % 3 == 0, e -> "Fizz")
.addCase(i -> i % 5 == 0, e -> "Buzz"))
.forEach(System.out::println);
IntCaseFunction
will also work with the IntInterval
example, passed as the parameter to the collect
method.
Note: I am a committer for Eclipse Collections.