Package net.sourceforge.pmd.util

Class IteratorUtil

java.lang.Object
net.sourceforge.pmd.util.IteratorUtil
public final class IteratorUtil extends Object
Operations for dealing with Iterators.
Author:
Clément Fournier
Since:
6.11.0

  • Method Details

    • takeWhile

      public static <T> Iterator<T> takeWhile(Iterator<T> iter, Predicate<? super T> predicate)

    • reverse

      public static <T> Iterator<T> reverse(Iterator<T> it)

    • flatMap

      public static <T, R> Iterator<R> flatMap(Iterator<? extends T> iter, Function<? super T,? extends @Nullable Iterator<? extends R>> f)

    • flatMapWithSelf

      public static <R> Iterator<R> flatMapWithSelf(Iterator<? extends R> iter, Function<? super R,? extends @Nullable Iterator<? extends R>> f)
      Like flatMap, but yields each element of the input iterator before yielding the results of the mapper function. Null elements of the input iterator are both yielded by the returned iterator and passed to the stepper. If the stepper returns null, that result is ignored.

    • filterNotNull

      public static <T> Iterator<@NonNull T> filterNotNull(Iterator<? extends T> it)

    • mapNotNull

      public static <T, R> Iterator<@NonNull R> mapNotNull(Iterator<? extends T> it, Function<@NonNull ? super T,@Nullable ? extends R> mapper)

    • filter

      public static <T> Iterator<T> filter(Iterator<? extends T> it, Predicate<? super T> filter)

    • peek

      public static <T> Iterator<T> peek(Iterator<? extends T> iter, Consumer<? super T> action)

    • map

      public static <T, R> Iterator<R> map(Iterator<? extends T> iter, Function<? super T,? extends R> mapper)

    • mapIterator

      public static <T, R> Iterable<R> mapIterator(Iterable<? extends T> iter, Function<? super Iterator<? extends T>,? extends Iterator<R>> mapper)
      Apply a transform on the iterator of an iterable.

    • iterate

      @SafeVarargs public static <T> Iterator<T> iterate(T... elements)

    • concat

      public static <T> Iterator<T> concat(Iterator<? extends T> as, Iterator<? extends T> bs)

    • distinct

      public static <T> Iterator<T> distinct(Iterator<? extends T> iter)

    • toList

      public static <T> List<T> toList(Iterator<? extends T> it)

    • toNonNullList

      public static <T> List<@NonNull T> toNonNullList(Iterator<? extends @Nullable T> it)

    • dropLast

      public static <T> Iterator<@NonNull T> dropLast(Iterator<? extends @Nullable T> it, int n)
      Remove the last n elements of the iterator. This uses n elements as a lookahead.

    • coerceWildcard

      public static <T> Iterator<T> coerceWildcard(Iterator<? extends T> it)
      Coerce an iterator with a wildcard. This is safe because the Iterator interface is covariant (not ListIterator though).

    • toIterable

      public static <T> Iterable<T> toIterable(Iterator<T> it)

    • count

      public static int count(Iterator<?> it)
      Counts the items in this iterator, exhausting it.

    • last

      public static <T> @Nullable T last(Iterator<? extends T> iterator)

    • getNth

      public static <T> @Nullable T getNth(Iterator<? extends T> iterator, int n)
      Returns the nth element of this iterator, or null if the iterator is shorter.
      Throws:
      IllegalArgumentException - If n is negative

    • advance

      public static void advance(Iterator<?> iterator, int n)
      Advance n times.

    • take

      public static <T> Iterator<T> take(Iterator<? extends T> iterator, int n)
      Limit the number of elements yielded by this iterator to the given number.

    • drop

      public static <T> Iterator<T> drop(Iterator<? extends T> source, int n)
      Produce an iterator whose first element is the nth element of the given source.

    • generate

      public static <T> Iterator<@NonNull T> generate(@Nullable T seed, Function<? super @NonNull T,? extends @Nullable T> stepper)
      Returns an iterator that applies a stepping function to the previous value yielded. Iteration stops on the first null value returned by the stepper.
      Type Parameters:
      T - Type of values
      Parameters:
      seed - First value. If null then the iterator is empty
      stepper - Step function

    • anyMatch

      public static <T> boolean anyMatch(Iterator<? extends T> iterator, Predicate<? super T> pred)
      Returns whether some element match the predicate. If empty then false is returned.

    • allMatch

      public static <T> boolean allMatch(Iterator<? extends T> iterator, Predicate<? super T> pred)
      Returns whether all elements match the predicate. If empty then true is returned.

    • noneMatch

      public static <T> boolean noneMatch(Iterator<? extends T> iterator, Predicate<? super T> pred)
      Returns whether no elements match the predicate. If empty then true is returned.

    • singletonIterator

      public static <T> Iterator<T> singletonIterator(T value)

    • asReversed

      public static <T> Iterable<T> asReversed(List<T> lst)

    • toStream

      public static <T> Stream<T> toStream(Iterator<? extends T> iter)

    • toStream

      public static <T> Stream<T> toStream(Iterable<T> iter)