Package it.unimi.dsi.fastutil.ints

Class IntOpenCustomHashSet

java.lang.Object
java.util.AbstractCollection<java.lang.Integer>
it.unimi.dsi.fastutil.ints.AbstractIntCollection
it.unimi.dsi.fastutil.ints.AbstractIntSet
it.unimi.dsi.fastutil.ints.IntOpenCustomHashSet
All Implemented Interfaces:
Hash, IntCollection, IntIterable, IntSet, java.io.Serializable, java.lang.Cloneable, java.lang.Iterable<java.lang.Integer>, java.util.Collection<java.lang.Integer>, java.util.Set<java.lang.Integer>
public class IntOpenCustomHashSet
extends AbstractIntSet
implements java.io.Serializable, java.lang.Cloneable, Hash
A type-specific hash set with a fast, small-footprint implementation whose hashing strategy is specified at creation time.

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:
Hash, HashCommon, Serialized Form

  • Constructor Details

    • IntOpenCustomHashSet

      public IntOpenCustomHashSet​(int expected, float f, IntHash.Strategy strategy)
      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.
      strategy - the strategy.

    • IntOpenCustomHashSet

      public IntOpenCustomHashSet​(int expected, IntHash.Strategy strategy)
      Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor.
      Parameters:
      expected - the expected number of elements in the hash set.
      strategy - the strategy.

    • IntOpenCustomHashSet

      public IntOpenCustomHashSet​(IntHash.Strategy strategy)
      Creates a new hash set with initial expected Hash.DEFAULT_INITIAL_SIZE elements and Hash.DEFAULT_LOAD_FACTOR as load factor.
      Parameters:
      strategy - the strategy.

    • IntOpenCustomHashSet

      public IntOpenCustomHashSet​(java.util.Collection<? extends java.lang.Integer> c, float f, IntHash.Strategy strategy)
      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.
      strategy - the strategy.

    • IntOpenCustomHashSet

      public IntOpenCustomHashSet​(java.util.Collection<? extends java.lang.Integer> c, IntHash.Strategy strategy)
      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.
      strategy - the strategy.

    • IntOpenCustomHashSet

      public IntOpenCustomHashSet​(IntCollection c, float f, IntHash.Strategy strategy)
      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.
      strategy - the strategy.

    • IntOpenCustomHashSet

      public IntOpenCustomHashSet​(IntCollection c, IntHash.Strategy strategy)
      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.
      strategy - the strategy.

    • IntOpenCustomHashSet

      public IntOpenCustomHashSet​(IntIterator i, float f, IntHash.Strategy strategy)
      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.
      strategy - the strategy.

    • IntOpenCustomHashSet

      public IntOpenCustomHashSet​(IntIterator i, IntHash.Strategy strategy)
      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.
      strategy - the strategy.

    • IntOpenCustomHashSet

      public IntOpenCustomHashSet​(java.util.Iterator<?> i, float f, IntHash.Strategy strategy)
      Creates a new hash set using elements provided by an iterator.
      Parameters:
      i - an iterator whose elements will fill the set.
      f - the load factor.
      strategy - the strategy.

    • IntOpenCustomHashSet

      public IntOpenCustomHashSet​(java.util.Iterator<?> i, IntHash.Strategy strategy)
      Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor using elements provided by an iterator.
      Parameters:
      i - an iterator whose elements will fill the set.
      strategy - the strategy.

    • IntOpenCustomHashSet

      public IntOpenCustomHashSet​(int[] a, int offset, int length, float f, IntHash.Strategy strategy)
      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.
      strategy - the strategy.

    • IntOpenCustomHashSet

      public IntOpenCustomHashSet​(int[] a, int offset, int length, IntHash.Strategy strategy)
      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.
      strategy - the strategy.

    • IntOpenCustomHashSet

      public IntOpenCustomHashSet​(int[] a, float f, IntHash.Strategy strategy)
      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.
      strategy - the strategy.

    • IntOpenCustomHashSet

      public IntOpenCustomHashSet​(int[] a, IntHash.Strategy strategy)
      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.
      strategy - the strategy.

  • Method Details

    • strategy

      public IntHash.Strategy strategy()
      Returns the hashing strategy.
      Returns:
      the hashing strategy of this custom hash set.

    • addAll

      public boolean addAll​(IntCollection c)
      Description copied from interface: IntCollection
      Adds all elements of the given type-specific collection to this collection.
      Specified by:
      addAll in interface IntCollection
      Overrides:
      addAll in class AbstractIntCollection
      Parameters:
      c - a type-specific collection.
      Returns:
      true if this collection changed as a result of the call.
      See Also:
      Collection.addAll(Collection)

    • addAll

      public boolean addAll​(java.util.Collection<? extends java.lang.Integer> c)
      Description copied from class: AbstractIntCollection
      Specified by:
      addAll in interface java.util.Collection<java.lang.Integer>
      Specified by:
      addAll in interface java.util.Set<java.lang.Integer>
      Overrides:
      addAll in class AbstractIntCollection

    • add

      public boolean add​(int k)
      Description copied from class: AbstractIntCollection
      Ensures that this collection contains the specified element (optional operation).
      Specified by:
      add in interface IntCollection
      Overrides:
      add in class AbstractIntCollection
      See Also:
      Collection.add(Object)

    • remove

      public boolean remove​(int k)
      Description copied from class: AbstractIntSet
      Removes an element from this set. Delegates to the type-specific rem() method implemented by type-specific abstract Collection superclass.
      Specified by:
      remove in interface IntSet
      Overrides:
      remove in class AbstractIntSet
      See Also:
      Collection.remove(Object)

    • contains

      public boolean contains​(int k)
      Description copied from class: AbstractIntCollection
      Returns true if this collection contains the specified element.
      Specified by:
      contains in interface IntCollection
      Overrides:
      contains in class AbstractIntCollection
      See Also:
      Collection.contains(Object)

    • clear

      public void clear()
      Specified by:
      clear in interface java.util.Collection<java.lang.Integer>
      Specified by:
      clear in interface java.util.Set<java.lang.Integer>
      Overrides:
      clear in class java.util.AbstractCollection<java.lang.Integer>

    • size

      public int size()
      Specified by:
      size in interface java.util.Collection<java.lang.Integer>
      Specified by:
      size in interface java.util.Set<java.lang.Integer>
      Specified by:
      size in class java.util.AbstractCollection<java.lang.Integer>

    • isEmpty

      public boolean isEmpty()
      Specified by:
      isEmpty in interface java.util.Collection<java.lang.Integer>
      Specified by:
      isEmpty in interface java.util.Set<java.lang.Integer>
      Overrides:
      isEmpty in class java.util.AbstractCollection<java.lang.Integer>

    • iterator

      public IntIterator iterator()
      Description copied from interface: IntCollection
      Returns a type-specific iterator on the elements of this collection.
      Specified by:
      iterator in interface java.util.Collection<java.lang.Integer>
      Specified by:
      iterator in interface IntCollection
      Specified by:
      iterator in interface IntIterable
      Specified by:
      iterator in interface IntSet
      Specified by:
      iterator in interface java.lang.Iterable<java.lang.Integer>
      Specified by:
      iterator in interface java.util.Set<java.lang.Integer>
      Specified by:
      iterator in class AbstractIntSet
      Returns:
      a type-specific iterator on the elements of this collection.
      See Also:
      Iterable.iterator()

    • spliterator

      public IntSpliterator spliterator()
      Description copied from interface: IntSet
      Returns a type-specific spliterator on the elements of this set.

      Set spliterators must report at least Spliterator.DISTINCT.

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

      Specified by:
      spliterator in interface java.util.Collection<java.lang.Integer>
      Specified by:
      spliterator in interface IntCollection
      Specified by:
      spliterator in interface IntIterable
      Specified by:
      spliterator in interface IntSet
      Specified by:
      spliterator in interface java.lang.Iterable<java.lang.Integer>
      Specified by:
      spliterator in interface java.util.Set<java.lang.Integer>
      Returns:
      a type-specific spliterator on the elements of this collection.

    • forEach

      public void forEach​(java.util.function.IntConsumer action)
      Description copied from interface: IntIterable
      Performs the given action for each element of this type-specific Iterable until all elements have been processed or the action throws an exception.
      Specified by:
      forEach in interface IntIterable
      Parameters:
      action - the action to be performed for each element.
      See Also:
      Iterable.forEach(java.util.function.Consumer)

    • trim

      public boolean trim()
      Rehashes this set, making the table as small as possible.

      This method rehashes the table to the smallest size satisfying the load factor. It can be used when the set will not be changed anymore, so to optimize access speed and size.

      If the table size is already the minimum possible, this method does nothing.

      Returns:
      true if there was enough memory to trim the set.
      See Also:
      trim(int)

    • trim

      public boolean trim​(int n)
      Rehashes this set if the table is too large.

      Let N be the smallest table size that can hold max(n,size()) entries, still satisfying the load factor. If the current table size is smaller than or equal to N, this method does nothing. Otherwise, it rehashes this set in a table of size N.

      This method is useful when reusing sets. Clearing a set leaves the table size untouched. If you are reusing a set many times, you can call this method with a typical size to avoid keeping around a very large table just because of a few large transient sets.

      Parameters:
      n - the threshold for the trimming.
      Returns:
      true if there was enough memory to trim the set.
      See Also:
      trim()

    • clone

      public IntOpenCustomHashSet clone()
      Returns a deep copy of this set.

      This method performs a deep copy of this hash set; the data stored in the set, however, is not cloned. Note that this makes a difference only for object keys.

      Returns:
      a deep copy of this set.

    • hashCode

      public int hashCode()
      Returns a hash code for this set. This method overrides the generic method provided by the superclass. Since equals() is not overriden, it is important that the value returned by this method is the same value as the one returned by the overriden method.
      Specified by:
      hashCode in interface java.util.Collection<java.lang.Integer>
      Specified by:
      hashCode in interface java.util.Set<java.lang.Integer>
      Overrides:
      hashCode in class AbstractIntSet
      Returns:
      a hash code for this set.