OptionalInt (Groovy JDK enhancements)

Methods Summary

Methods
Return type	Name and parameters
`OptionalInt`	`filter(IntPredicate test)` If a value is present in the `OptionalInt`, tests the value using the given predicate and returns the optional if the test returns true or else empty.
`int`	`get()` If a value is present in the `OptionalInt`, returns the value, otherwise throws `NoSuchElementException`.
`Optional`	`mapToObj(IntFunction mapper)` If a value is present in the `OptionalInt`, returns an `Optional` consisting of the result of applying the given function to the value or else empty.
`IntStream`	`stream()` If a value is present in the OptionalInt, returns an IntStream with the value as its source or else an empty stream.

Methods inherited from class java.lang.Object

addShutdownHook, any, any, asBoolean, asType, collect, collect, collect, dump, each, eachMatch, eachMatch, eachWithIndex, every, every, find, find, findAll, findAll, findIndexOf, findIndexOf, findIndexValues, findIndexValues, findLastIndexOf, findLastIndexOf, findResult, findResult, findResult, findResult, getAt, getMetaClass, getMetaPropertyValues, getProperties, grep, grep, hasProperty, identity, inject, inject, inspect, invokeMethod, is, isCase, isNotCase, iterator, metaClass, print, print, printf, printf, println, println, println, putAt, respondsTo, respondsTo, setMetaClass, split, sprintf, sprintf, stream, tap, toString, use, use, use, with, with, withCloseable, withStream, withTraits

- Methods Detail
  - public OptionalInt filter(IntPredicate test)
    
    If a value is present in the OptionalInt, tests the value using the given predicate and returns the optional if the test returns true or else empty.
```
assert !OptionalInt.empty().filter(i -> true).isPresent()
assert  OptionalInt.of(1234).filter(i -> true).isPresent()
assert !OptionalInt.of(1234).filter(i -> false).isPresent()
assert  OptionalInt.of(1234).filter(i -> true).getAsInt() == 1234
```
    Parameters:
    
    Since:
    
    3.0.0
  - public int get()
    
    If a value is present in the OptionalInt, returns the value, otherwise throws NoSuchElementException.
```
assert OptionalInt.of(1234).get() == 1234
```
    Since:
    
    3.0.0
  - public Optional mapToObj(IntFunction mapper)
    
    If a value is present in the OptionalInt, returns an Optional consisting of the result of applying the given function to the value or else empty.
```
assert !OptionalInt.empty().mapToObj(x -> new Object()).isPresent()
assert  OptionalInt.of(1234).mapToObj(x -> new Object()).isPresent()
assert !OptionalInt.of(1234).mapToObj(x -> null).isPresent()
assert  OptionalInt.of(1234).mapToObj(Integer::toString).get() == '1234'
```
    Parameters:
    
    Since:
    
    3.0.0
  - public IntStream stream()
    
    If a value is present in the OptionalInt, returns an IntStream with the value as its source or else an empty stream.
    
    Since:
    
    3.0.0