Package it.unimi.dsi.fastutil.objects

Interface ReferenceList<K>

All Superinterfaces:
Collection<K>, Iterable<K>, List<K>, ObjectIterable<K>, ReferenceCollection<K>, SequencedCollection<K>
All Known Implementing Classes:
AbstractReferenceList, AbstractReferenceList.ReferenceRandomAccessSubList, AbstractReferenceList.ReferenceSubList, ReferenceArrayList, ReferenceImmutableList, ReferenceLists.EmptyList, ReferenceLists.Singleton, ReferenceLists.SynchronizedList, ReferenceLists.SynchronizedRandomAccessList, ReferenceLists.UnmodifiableList, ReferenceLists.UnmodifiableRandomAccessList
public interface ReferenceList<K> extends List<K>, ReferenceCollection<K>
A type-specific List; provides some additional methods that use polymorphism to avoid (un)boxing.

Additionally, this interface strengthens iterator(), listIterator(), listIterator(int) and subList(int,int). The former had been already strengthened upstream, but unfortunately List re-specifies it.

This interface specifies reference equality semantics (members will be compared equal with == instead of equals), which may result in breaks in contract if attempted to be used with non reference-equality semantics based Lists. For example, a aReferenceList.equals(aObjectList) may return different a different result then aObjectList.equals(aReferenceList), in violation of equals's contract requiring it being symmetric.

Besides polymorphic methods, this interfaces specifies methods to copy into an array or remove contiguous sublists. Although the abstract implementation of this interface provides simple, one-by-one implementations of these methods, it is expected that concrete implementation override them with optimized versions.

See Also:

  • Method Details

    • iterator

      ObjectListIterator<K> iterator()
      Returns a type-specific iterator on the elements of this list.
      Specified by:
      iterator in interface Collection<K>
      Specified by:
      iterator in interface Iterable<K>
      Specified by:
      iterator in interface List<K>
      Specified by:
      iterator in interface ObjectIterable<K>
      Specified by:
      iterator in interface ReferenceCollection<K>
      Returns:
      an iterator on the elements of this list.
      See Also:
      API Notes:
      This specification strengthens the one given in List.iterator(). It would not be normally necessary, but Iterable.iterator() is bizarrily re-specified in List.

      Also, this is generally the only iterator method subclasses should override.

    • spliterator

      default ObjectSpliterator<K> spliterator()
      Returns a type-specific spliterator on the elements of this list.

      List spliterators must report at least Spliterator.SIZED and Spliterator.ORDERED.

      See List.spliterator() for more documentation on the requirements of the returned spliterator.

      Specified by:
      spliterator in interface Collection<K>
      Specified by:
      spliterator in interface Iterable<K>
      Specified by:
      spliterator in interface List<K>
      Specified by:
      spliterator in interface ObjectIterable<K>
      Specified by:
      spliterator in interface ReferenceCollection<K>
      Returns:
      a type-specific spliterator on the elements of this collection.
      Since:
      8.5.0
      API Notes:
      This specification strengthens the one given in Collection.spliterator(), which was already strengthened in the corresponding type-specific class, but was weakened by the fact that this interface extends List.

      Also, this is generally the only spliterator method subclasses should override.

      Implementation Specification:
      The default implementation returns a late-binding spliterator (see Spliterator for documentation on what binding policies mean).
      • For RandomAccess lists, this will return a spliterator that calls the type-specific List.get(int) method on the appropriate indexes.
      • Otherwise, the spliterator returned will wrap this instance's type specific iterator().

      In either case, the spliterator reports Spliterator.SIZED, Spliterator.SUBSIZED, and Spliterator.ORDERED.

      Implementation Notes:
      As the non-RandomAccess case is based on the iterator, and Iterator is an inherently linear API, the returned spliterator will yield limited performance gains when run in parallel contexts, as the returned spliterator's trySplit() will have linear runtime.

      For RandomAccess lists, the parallel performance should be reasonable assuming List.get(int) is truly constant time like RandomAccess suggests.

    • listIterator

      ObjectListIterator<K> listIterator()
      Returns a type-specific list iterator on the list.
      Specified by:
      listIterator in interface List<K>
      See Also:

    • listIterator

      ObjectListIterator<K> listIterator(int index)
      Returns a type-specific list iterator on the list starting at a given index.
      Specified by:
      listIterator in interface List<K>
      See Also:

    • subList

      ReferenceList<K> subList(int from, int to)
      Returns a type-specific view of the portion of this list from the index from, inclusive, to the index to, exclusive.
      Specified by:
      subList in interface List<K>
      See Also:
      API Notes:
      This specification strengthens the one given in List.subList(int,int).

    • size

      void size(int size)
      Sets the size of this list.

      If the specified size is smaller than the current size, the last elements are discarded. Otherwise, they are filled with 0/null/false.

      Parameters:
      size - the new size.

    • getElements

      void getElements(int from, Object[] a, int offset, int length)
      Copies (hopefully quickly) elements of this type-specific list into the given array.
      Parameters:
      from - the start index (inclusive).
      a - the destination array.
      offset - the offset into the destination array where to store the first element copied.
      length - the number of elements to be copied.

    • removeElements

      void removeElements(int from, int to)
      Removes (hopefully quickly) elements of this type-specific list.
      Parameters:
      from - the start index (inclusive).
      to - the end index (exclusive).

    • addElements

      void addElements(int index, K[] a)
      Add (hopefully quickly) elements to this type-specific list.
      Parameters:
      index - the index at which to add elements.
      a - the array containing the elements.

    • addElements

      void addElements(int index, K[] a, int offset, int length)
      Add (hopefully quickly) elements to this type-specific list.
      Parameters:
      index - the index at which to add elements.
      a - the array containing the elements.
      offset - the offset of the first element to add.
      length - the number of elements to add.

    • setElements

      default void setElements(K[] a)
      Set (hopefully quickly) elements to match the array given.
      Parameters:
      a - the array containing the elements.
      Since:
      8.3.0

    • setElements

      default void setElements(int index, K[] a)
      Set (hopefully quickly) elements to match the array given.
      Parameters:
      index - the index at which to start setting elements.
      a - the array containing the elements.
      Since:
      8.3.0

    • setElements

      default void setElements(int index, K[] a, int offset, int length)
      Set (hopefully quickly) elements to match the array given. Sets each in this list to the corresponding elements in the array, as if by 
       ListIterator iter = listIterator(index);
 int i = 0;
 while (i < length) {
        iter.next();
        iter.set(a[offset + i++]);
 }
      However, the exact implementation may be more efficient, taking into account whether random access is faster or not, or at the discretion of subclasses, abuse internals.
      Parameters:
      index - the index at which to start setting elements.
      a - the array containing the elements
      offset - the offset of the first element to add.
      length - the number of elements to add.
      Since:
      8.3.0

    • addAll

      default boolean addAll(int index, ReferenceList<? extends K> l)
      Inserts all of the elements in the specified type-specific list into this type-specific list at the specified position (optional operation).
      See Also:
      API Notes:
      This method exists only for the sake of efficiency: override are expected to use getElements(int, java.lang.Object[], int, int)/addElements(int, K[]).
      Implementation Specification:
      This method delegates to the one accepting a collection, but it might be implemented more efficiently.

    • addAll

      default boolean addAll(ReferenceList<? extends K> l)
      Appends all of the elements in the specified type-specific list to the end of this type-specific list (optional operation).
      See Also:
      Implementation Specification:
      This method delegates to the index-based version, passing List.size() as first argument.

    • of

      static <K> ReferenceList<K> of()
      Returns an immutable empty list.
      Returns:
      an immutable empty list.

    • of

      static <K> ReferenceList<K> of(K e)
      Returns an immutable list with the element given.
      Parameters:
      e - the element that the returned list will contain.
      Returns:
      an immutable list containing e.

    • of

      static <K> ReferenceList<K> of(K e0, K e1)
      Returns an immutable list with the elements given.
      Parameters:
      e0 - the first element.
      e1 - the second element.
      Returns:
      an immutable list containing e0 and e1.

    • of

      static <K> ReferenceList<K> of(K e0, K e1, K e2)
      Returns an immutable list with the elements given.
      Parameters:
      e0 - the first element.
      e1 - the second element.
      e2 - the third element.
      Returns:
      an immutable list containing e0, e1, and e2.

    • of

      @SafeVarargs static <K> ReferenceList<K> of(K... a)
      Returns an immutable list with the elements given.

      Note that this method does not perform a defensive copy.

      Parameters:
      a - a list of elements that will be used to initialize the immutable list.
      Returns:
      an immutable list containing the elements of a.

    • sort

      default void sort(Comparator<? super K> comparator)
      Sorts this list using a sort assured to be stable.

      Pass null to sort using natural ordering.

      Unless a subclass specifies otherwise, the results of the method if the list is concurrently modified during the sort are unspecified.

      Specified by:
      sort in interface List<K>
      Since:
      8.5.0
      Implementation Specification:
      The default implementation dumps the elements into an array using List.toArray(), sorts the array, then replaces all elements using the setElements(K[]) function.

    • unstableSort

      default void unstableSort(Comparator<? super K> comparator)
      Sorts this list using a sort not assured to be stable. This differs from List.sort(java.util.Comparator) in that the results are not assured to be stable, but may be a bit faster.

      Pass null to sort using natural ordering.

      Unless a subclass specifies otherwise, the results of the method if the list is concurrently modified during the sort are unspecified.

      Since:
      8.3.0
      Implementation Specification:
      The default implementation dumps the elements into an array using List.toArray(), sorts the array, then replaces all elements using the setElements(K[]) function.