Package org.apache.commons.collections4.iterators

Class EmptyListIterator<E>

java.lang.Object
org.apache.commons.collections4.iterators.EmptyListIterator<E>
Type Parameters:
E - the type of elements returned by this iterator.
All Implemented Interfaces:
Iterator<E>, ListIterator<E>, OrderedIterator<E>, ResettableIterator<E>, ResettableListIterator<E>
public class EmptyListIterator<E> extends Object implements ResettableListIterator<E>
Provides an implementation of an empty list iterator.

This class provides an implementation of an empty list iterator. This class provides for binary compatibility between Commons Collections 2.1.1 and 3.1 due to issues with IteratorUtils.

Since:
2.1.1 and 3.1

  • Field Details

    • RESETTABLE_INSTANCE

      public static final ResettableListIterator RESETTABLE_INSTANCE
      Singleton instance of the iterator.
      Since:
      3.1

    • INSTANCE

      public static final ListIterator INSTANCE
      Singleton instance of the iterator.
      Since:
      2.1.1 and 3.1

  • Method Details

    • emptyListIterator

      public static <E> ListIterator<E> emptyListIterator()
      Gets a typed instance of the iterator.
      Type Parameters:
      E - the element type
      Returns:
      ListIterator<E>

    • resettableEmptyListIterator

      public static <E> ResettableListIterator<E> resettableEmptyListIterator()
      Gets a typed instance of the iterator.
      Type Parameters:
      E - the element type
      Returns:
      ResettableListIterator<E>

    • add

      @Deprecated public void add(E ignored)
      Deprecated.
      Will be removed in 5.0 without replacement.
      Always throws UnsupportedOperationException.
      Parameters:
      ignored - ignore.
      Throws:
      UnsupportedOperationException - Always thrown.

    • hasNext

      public boolean hasNext()
      Always returns false, this iterator contains no elements.
      Specified by:
      hasNext in interface Iterator<E>
      Returns:
      Always false.

    • hasPrevious

      public boolean hasPrevious()
      Always returns false, this iterator contains no elements.
      Returns:
      Always false.

    • next

      public E next()
      Always throws IllegalStateException, this iterator contains no elements.
      Specified by:
      next in interface Iterator<E>
      Returns:
      Always throws IllegalStateException.
      Throws:
      IllegalStateException - Always thrown.

    • nextIndex

      public int nextIndex()
      Always returns 0, this iterator contains no elements.
      Returns:
      Always returns 0.

    • previous

      public E previous()
      Always throws IllegalStateException, this iterator contains no elements.
      Returns:
      Always throws IllegalStateException.
      Throws:
      IllegalStateException - Always thrown.

    • previousIndex

      public int previousIndex()
      Always returns -1, this iterator contains no elements.
      Returns:
      Always returns -1.

    • remove

      public void remove()
      Always throws IllegalStateException, this iterator contains no elements.
      Specified by:
      remove in interface Iterator<E>
      Throws:
      IllegalStateException - Always thrown.

    • reset

      public void reset()
      Description copied from interface: ResettableIterator
      Resets the iterator back to the position at which the iterator was created.
      Specified by:
      reset in interface ResettableIterator<E>

    • set

      public void set(E ignored)
      Always throws IllegalStateException, this iterator contains no elements.
      Parameters:
      ignored - ignored.
      Throws:
      IllegalStateException - Always thrown.