Class CharOpenHashSet

  • All Implemented Interfaces:
    CharCollection, CharIterable, CharSet, Hash, java.io.Serializable, java.lang.Cloneable, java.lang.Iterable<java.lang.Character>, java.util.Collection<java.lang.Character>, java.util.Set<java.lang.Character>

    public class CharOpenHashSet
    extends AbstractCharSet
    implements java.io.Serializable, java.lang.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:
    Hash, HashCommon, Serialized Form
    • Constructor Detail

      • CharOpenHashSet

        public CharOpenHashSet​(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.
      • CharOpenHashSet

        public CharOpenHashSet​(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.
      • CharOpenHashSet

        public CharOpenHashSet​(java.util.Collection<? extends java.lang.Character> 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.
      • CharOpenHashSet

        public CharOpenHashSet​(java.util.Collection<? extends java.lang.Character> 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.
      • CharOpenHashSet

        public CharOpenHashSet​(CharCollection 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.
      • CharOpenHashSet

        public CharOpenHashSet​(CharCollection 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.
      • CharOpenHashSet

        public CharOpenHashSet​(CharIterator 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.
      • CharOpenHashSet

        public CharOpenHashSet​(CharIterator 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.
      • CharOpenHashSet

        public CharOpenHashSet​(java.util.Iterator<?> i,
                               float f)
        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.
      • CharOpenHashSet

        public CharOpenHashSet​(java.util.Iterator<?> i)
        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.
      • CharOpenHashSet

        public CharOpenHashSet​(char[] 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.
      • CharOpenHashSet

        public CharOpenHashSet​(char[] 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.
      • CharOpenHashSet

        public CharOpenHashSet​(char[] 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.
      • CharOpenHashSet

        public CharOpenHashSet​(char[] 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 Detail

      • of

        public static CharOpenHashSet of()
        Creates a new empty hash set.
        Returns:
        a new empty hash set.
      • of

        public static CharOpenHashSet of​(char e0,
                                         char e1)
        Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor using the elements given.
        Parameters:
        e0 - the first element.
        e1 - the second element.
        Returns:
        a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor containing e0 and e1.
        Throws:
        java.lang.IllegalArgumentException - if there were duplicate entries.
      • of

        public static CharOpenHashSet of​(char e0,
                                         char e1,
                                         char e2)
        Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor using the elements given.
        Parameters:
        e0 - the first element.
        e1 - the second element.
        e2 - the third element.
        Returns:
        a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor containing e0, e1, and e2.
        Throws:
        java.lang.IllegalArgumentException - if there were duplicate entries.
      • of

        public static CharOpenHashSet of​(char... a)
        Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor using a list of elements.
        Parameters:
        a - a list of elements that will be used to initialize the new hash set.
        Returns:
        a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor containing the elements of a.
        Throws:
        java.lang.IllegalArgumentException - if a duplicate entry was encountered.
      • ensureCapacity

        public void ensureCapacity​(int capacity)
        Ensures that this set can hold a certain number of elements without rehashing.
        Parameters:
        capacity - a number of elements; there will be no rehashing unless the set size exceeds this number.
      • addAll

        public boolean addAll​(CharCollection c)
        Description copied from interface: CharCollection
        Adds all elements of the given type-specific collection to this collection.
        Specified by:
        addAll in interface CharCollection
        Overrides:
        addAll in class AbstractCharCollection
        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.Character> c)
        Description copied from class: AbstractCharCollection
        Specified by:
        addAll in interface java.util.Collection<java.lang.Character>
        Specified by:
        addAll in interface java.util.Set<java.lang.Character>
        Overrides:
        addAll in class AbstractCharCollection
      • remove

        public boolean remove​(char k)
        Description copied from class: AbstractCharSet
        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 CharSet
        Overrides:
        remove in class AbstractCharSet
        See Also:
        Collection.remove(Object)
      • clear

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

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

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

        public CharIterator iterator()
        Description copied from interface: CharCollection
        Returns a type-specific iterator on the elements of this collection.
        Specified by:
        iterator in interface CharCollection
        Specified by:
        iterator in interface CharIterable
        Specified by:
        iterator in interface CharSet
        Specified by:
        iterator in interface java.util.Collection<java.lang.Character>
        Specified by:
        iterator in interface java.lang.Iterable<java.lang.Character>
        Specified by:
        iterator in interface java.util.Set<java.lang.Character>
        Specified by:
        iterator in class AbstractCharSet
        Returns:
        a type-specific iterator on the elements of this collection.
        See Also:
        Iterable.iterator()
      • spliterator

        public CharSpliterator spliterator()
        Description copied from interface: CharSet
        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 CharCollection
        Specified by:
        spliterator in interface CharIterable
        Specified by:
        spliterator in interface CharSet
        Specified by:
        spliterator in interface java.util.Collection<java.lang.Character>
        Specified by:
        spliterator in interface java.lang.Iterable<java.lang.Character>
        Specified by:
        spliterator in interface java.util.Set<java.lang.Character>
        Returns:
        a type-specific spliterator on the elements of this collection.
      • forEach

        public void forEach​(CharConsumer action)
        Description copied from interface: CharIterable
        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 CharIterable
        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 CharOpenHashSet 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.Character>
        Specified by:
        hashCode in interface java.util.Set<java.lang.Character>
        Overrides:
        hashCode in class AbstractCharSet
        Returns:
        a hash code for this set.