Package it.unimi.dsi.fastutil.objects

Class ReferenceOpenHashSet<K>

java.lang.Object
java.util.AbstractCollection<K>
it.unimi.dsi.fastutil.objects.AbstractReferenceCollection<K>
it.unimi.dsi.fastutil.objects.AbstractReferenceSet<K>
it.unimi.dsi.fastutil.objects.ReferenceOpenHashSet<K>
All Implemented Interfaces:
Hash, ObjectIterable<K>, ReferenceCollection<K>, ReferenceSet<K>, Serializable, Cloneable, Iterable<K>, Collection<K>, Set<K>
public class ReferenceOpenHashSet<K> extends AbstractReferenceSet<K> implements Serializable, Cloneable, Hash
A type-specific hash set with with a fast, small-footprint implementation.

Instances of this class use a hash table to represent a set. The table is filled up to a specified load factor, and then doubled in size to accommodate new entries. If the table is emptied below one fourth of the load factor, it is halved in size; however, the table is never reduced to a size smaller than that at creation time: this approach makes it possible to create sets with a large capacity in which insertions and deletions do not cause immediately rehashing. Moreover, halving is not performed when deleting entries from an iterator, as it would interfere with the iteration process.

Note that clear() does not modify the hash table size. Rather, a family of trimming methods lets you control the size of the table; this is particularly useful if you reuse instances of this class.

See Also:

  • Constructor Details

    • ReferenceOpenHashSet

      public ReferenceOpenHashSet(int expected, float f)
      Creates a new hash set.

      The actual table size will be the least power of two greater than expected/f.

      Parameters:
      expected - the expected number of elements in the hash set.
      f - the load factor.

    • ReferenceOpenHashSet

      public ReferenceOpenHashSet(int expected)
      Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor.
      Parameters:
      expected - the expected number of elements in the hash set.

    • ReferenceOpenHashSet

      public ReferenceOpenHashSet()
      Creates a new hash set with initial expected Hash.DEFAULT_INITIAL_SIZE elements and Hash.DEFAULT_LOAD_FACTOR as load factor.

    • ReferenceOpenHashSet

      public ReferenceOpenHashSet(Collection<? extends K> c, float f)
      Creates a new hash set copying a given collection.
      Parameters:
      c - a Collection to be copied into the new hash set.
      f - the load factor.

    • ReferenceOpenHashSet

      public ReferenceOpenHashSet(Collection<? extends K> c)
      Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given collection.
      Parameters:
      c - a Collection to be copied into the new hash set.

    • ReferenceOpenHashSet

      public ReferenceOpenHashSet(ReferenceCollection<? extends K> c, float f)
      Creates a new hash set copying a given type-specific collection.
      Parameters:
      c - a type-specific collection to be copied into the new hash set.
      f - the load factor.

    • ReferenceOpenHashSet

      public ReferenceOpenHashSet(ReferenceCollection<? extends K> c)
      Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific collection.
      Parameters:
      c - a type-specific collection to be copied into the new hash set.

    • ReferenceOpenHashSet

      public ReferenceOpenHashSet(Iterator<? extends K> i, float f)
      Creates a new hash set using elements provided by a type-specific iterator.
      Parameters:
      i - a type-specific iterator whose elements will fill the set.
      f - the load factor.

    • ReferenceOpenHashSet

      public ReferenceOpenHashSet(Iterator<? extends K> i)
      Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor using elements provided by a type-specific iterator.
      Parameters:
      i - a type-specific iterator whose elements will fill the set.

    • ReferenceOpenHashSet

      public ReferenceOpenHashSet(K[] a, int offset, int length, float f)
      Creates a new hash set and fills it with the elements of a given array.
      Parameters:
      a - an array whose elements will be used to fill the set.
      offset - the first element to use.
      length - the number of elements to use.
      f - the load factor.

    • ReferenceOpenHashSet

      public ReferenceOpenHashSet(K[] a, int offset, int length)
      Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor and fills it with the elements of a given array.
      Parameters:
      a - an array whose elements will be used to fill the set.
      offset - the first element to use.
      length - the number of elements to use.

    • ReferenceOpenHashSet

      public ReferenceOpenHashSet(K[] a, float f)
      Creates a new hash set copying the elements of an array.
      Parameters:
      a - an array to be copied into the new hash set.
      f - the load factor.

    • ReferenceOpenHashSet

      public ReferenceOpenHashSet(K[] a)
      Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor copying the elements of an array.
      Parameters:
      a - an array to be copied into the new hash set.

  • Method Details