it.unimi.dsi.fastutil.ints
Class IntOpenCustomHashSet

java.lang.Object
  extended by java.util.AbstractCollection<java.lang.Integer>
      extended by it.unimi.dsi.fastutil.ints.AbstractIntCollection
          extended by it.unimi.dsi.fastutil.ints.AbstractIntSet
              extended by 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 enlarged as needed by doubling its size when new entries are created, but it is never made smaller (even on a clear()). A family of trimming methods lets you control the size of the table; this is particularly useful if you reuse instances of this class.

Warning: The implementation of this class has significantly changed in fastutil 6.1.0. Please read the comments about this issue in the section “Faster Hash Tables” of the overview.

See Also:
Hash, HashCommon, Serialized Form

Nested Class Summary
 
Nested classes/interfaces inherited from interface it.unimi.dsi.fastutil.Hash
Hash.Strategy<K>
 
Field Summary
 
Fields inherited from interface it.unimi.dsi.fastutil.Hash
DEFAULT_GROWTH_FACTOR, DEFAULT_INITIAL_SIZE, DEFAULT_LOAD_FACTOR, FAST_LOAD_FACTOR, FREE, OCCUPIED, PRIMES, REMOVED, VERY_FAST_LOAD_FACTOR
 
Constructor Summary
IntOpenCustomHashSet(java.util.Collection<? extends java.lang.Integer> c, float f, IntHash.Strategy strategy)
          Creates a new hash set copying a given collection.
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.
IntOpenCustomHashSet(int[] a, float f, IntHash.Strategy strategy)
          Creates a new hash set copying the elements of an array.
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.
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.
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.
IntOpenCustomHashSet(IntCollection c, float f, IntHash.Strategy strategy)
          Creates a new hash set copying a given type-specific collection.
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.
IntOpenCustomHashSet(int expected, float f, IntHash.Strategy strategy)
          Creates a new hash set.
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.
IntOpenCustomHashSet(int expected, IntHash.Strategy strategy)
          Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor.
IntOpenCustomHashSet(IntIterator i, float f, IntHash.Strategy strategy)
          Creates a new hash set using elements provided by a type-specific iterator.
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.
IntOpenCustomHashSet(java.util.Iterator<?> i, float f, IntHash.Strategy strategy)
          Creates a new hash set using elements provided by an iterator.
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.
 
Method Summary
 boolean add(int k)
           
 void clear()
           
 IntOpenCustomHashSet clone()
          Returns a deep copy of this set.
 boolean contains(int k)
           
 int growthFactor()
          Deprecated. Since fastutil 6.1.0, hash tables are doubled when they are too full.
 void growthFactor(int growthFactor)
          Deprecated. Since fastutil 6.1.0, hash tables are doubled when they are too full.
 int hashCode()
          Returns a hash code for this set.
 boolean isEmpty()
           
 IntIterator iterator()
          Returns a type-specific iterator on the elements of this collection.
 boolean rehash()
          Deprecated. A no-op.
 boolean remove(int k)
          Removes an element from this set.
 int size()
           
 IntHash.Strategy strategy()
          Returns the hashing strategy.
 boolean trim()
          Rehashes this set, making the table as small as possible.
 boolean trim(int n)
          Rehashes this set if the table is too large.
 
Methods inherited from class it.unimi.dsi.fastutil.ints.AbstractIntSet
equals, rem, remove
 
Methods inherited from class it.unimi.dsi.fastutil.ints.AbstractIntCollection
add, addAll, addAll, contains, containsAll, containsAll, intIterator, rem, removeAll, removeAll, retainAll, retainAll, toArray, toArray, toArray, toIntArray, toIntArray, toString
 
Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface it.unimi.dsi.fastutil.ints.IntCollection
addAll, containsAll, intIterator, removeAll, retainAll, toArray, toArray, toIntArray, toIntArray
 
Methods inherited from interface java.util.Set
add, addAll, contains, containsAll, removeAll, retainAll, toArray, toArray
 

Constructor Detail

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 Detail

strategy

public IntHash.Strategy strategy()
Returns the hashing strategy.

Returns:
the hashing strategy of this custom hash set.

add

public boolean add(int k)
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 interface: IntSet
Removes an element from this set.

Note that the corresponding method of the type-specific collection is rem(). This unfortunate situation is caused by the clash with the similarly named index-based method in the List interface.

Specified by:
remove in interface IntSet
Overrides:
remove in class AbstractIntSet
See Also:
Collection.remove(Object)

contains

public boolean contains(int k)
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 AbstractIntCollection

growthFactor

@Deprecated
public void growthFactor(int growthFactor)
Deprecated. Since fastutil 6.1.0, hash tables are doubled when they are too full.

A no-op for backward compatibility.

Parameters:
growthFactor - unused.

growthFactor

@Deprecated
public int growthFactor()
Deprecated. Since fastutil 6.1.0, hash tables are doubled when they are too full.

Gets the growth factor (2).

Returns:
the growth factor of this set, which is fixed (2).
See Also:
growthFactor(int)

iterator

public IntIterator iterator()
Description copied from interface: IntCollection
Returns a type-specific iterator on the elements of this collection.

Note that this specification strengthens the one given in Iterable.iterator(), which was already strengthened in the corresponding type-specific class, but was weakened by the fact that this interface extends Collection.

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.Collection<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.

rehash

@Deprecated
public boolean rehash()
Deprecated. A no-op.

A no-op for backward compatibility. The kind of tables implemented by this class never need rehashing.

If you need to reduce the table size to fit exactly this set, use trim().

Returns:
true.
See Also:
trim()

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.

Overrides:
clone in class java.lang.Object
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.