it.unimi.dsi.fastutil.objects
Class ObjectLinkedOpenCustomHashSet<K>

java.lang.Object
  extended by it.unimi.dsi.fastutil.objects.AbstractObjectCollection<K>
      extended by it.unimi.dsi.fastutil.objects.AbstractObjectSet<K>
          extended by it.unimi.dsi.fastutil.objects.AbstractObjectSortedSet<K>
              extended by it.unimi.dsi.fastutil.objects.ObjectLinkedOpenCustomHashSet<K>
All Implemented Interfaces:
Hash, ObjectCollection<K>, ObjectIterable<K>, ObjectSet<K>, ObjectSortedSet<K>, java.io.Serializable, java.lang.Cloneable, java.lang.Iterable<K>, java.util.Collection<K>, java.util.Set<K>, java.util.SortedSet<K>

public class ObjectLinkedOpenCustomHashSet<K>
extends AbstractObjectSortedSet<K>
implements java.io.Serializable, java.lang.Cloneable, Hash

A type-specific linked hash set with with a fast, small-footprint implementation.

Instances of this class use a hash table to represent a set. The table is enlarged as needed 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.

The enlargement speed is controlled by the growth factor, a positive number. If the growth factor is p, then the table is enlarged each time roughly by a factor 2p/16. By default, p is Hash.DEFAULT_GROWTH_FACTOR, which means that the table is doubled at each enlargement, but one can easily set more or less aggressive policies by calling growthFactor(int) (note that the growth factor is not serialized: deserialized tables gets the default growth factor).

This class implements the interface of a sorted set, so to allow easy access of the iteration order: for instance, you can get the first element in iteration order with first() without having to create an iterator; however, this class partially violates the SortedSet contract because all subset methods throw an exception and comparator() returns always null.

The iterators provided by this class are type-specific list iterators. However, creation of an iterator using a starting point is going to be very expensive, as the chosen starting point must be linearly searched for, unless it is last(), in which case the iterator is created in constant time.

Note that deletions in a linked table require scanning the list until the element to be removed is found. The only exceptions are the first element, the last element, and deletions performed using an iterator.

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
static long serialVersionUID
           
 
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
ObjectLinkedOpenCustomHashSet(java.util.Collection<? extends K> c, float f, Hash.Strategy<K> strategy)
          Creates a new hash set copying a given collection.
ObjectLinkedOpenCustomHashSet(java.util.Collection<? extends K> c, Hash.Strategy<K> strategy)
          Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given collection.
ObjectLinkedOpenCustomHashSet(Hash.Strategy<K> strategy)
          Creates a new hash set with Hash.DEFAULT_INITIAL_SIZE elements and Hash.DEFAULT_LOAD_FACTOR as load factor.
ObjectLinkedOpenCustomHashSet(int n, float f, Hash.Strategy<K> strategy)
          Creates a new hash set.
ObjectLinkedOpenCustomHashSet(int n, Hash.Strategy<K> strategy)
          Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor.
ObjectLinkedOpenCustomHashSet(K[] a, float f, Hash.Strategy<K> strategy)
          Creates a new hash set copying the elements of an array.
ObjectLinkedOpenCustomHashSet(K[] a, Hash.Strategy<K> strategy)
          Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor copying the elements of an array.
ObjectLinkedOpenCustomHashSet(K[] a, int offset, int length, float f, Hash.Strategy<K> strategy)
          Creates a new hash set and fills it with the elements of a given array.
ObjectLinkedOpenCustomHashSet(K[] a, int offset, int length, Hash.Strategy<K> strategy)
          Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor and fills it with the elements of a given array.
ObjectLinkedOpenCustomHashSet(ObjectCollection<? extends K> c, float f, Hash.Strategy<K> strategy)
          Creates a new hash set copying a given type-specific collection.
ObjectLinkedOpenCustomHashSet(ObjectCollection<? extends K> c, Hash.Strategy<K> strategy)
          Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific collection.
ObjectLinkedOpenCustomHashSet(ObjectIterator<K> i, float f, Hash.Strategy<K> strategy)
          Creates a new hash set using elements provided by a type-specific iterator.
ObjectLinkedOpenCustomHashSet(ObjectIterator<K> i, Hash.Strategy<K> strategy)
          Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor using elements provided by a type-specific iterator.
 
Method Summary
 boolean add(K k)
           
 void clear()
           
 java.lang.Object clone()
          Returns a deep copy of this set.
 java.util.Comparator<? super K> comparator()
           
 boolean contains(java.lang.Object k)
           
 K first()
          Returns the first element of this set in iteration order.
 int growthFactor()
          Gets the growth factor.
 void growthFactor(int growthFactor)
          Sets the growth factor.
 int hashCode()
          Returns a hash code for this set.
 ObjectSortedSet<K> headSet(K to)
          Returns a view of the portion of this sorted set whose elements are strictly less than toElement.
 boolean isEmpty()
           
 ObjectBidirectionalIterator<K> iterator()
          Returns a type-specific iterator on the elements of this collection.
 ObjectBidirectionalIterator<K> iterator(K from)
          Returns a type-specific list iterator on the elements in this set, starting from a given element of the set.
 K last()
          Returns the last element of this set in iteration order.
 boolean rehash()
          Rehashes this set without changing the table size.
 boolean remove(java.lang.Object k)
          Removes an element from this set.
 int size()
           
 Hash.Strategy<K> strategy()
          Returns the hashing strategy.
 ObjectSortedSet<K> subSet(K from, K to)
          Returns a view of the portion of this sorted set whose elements range from fromElement, inclusive, to toElement, exclusive.
 ObjectSortedSet<K> tailSet(K from)
          Returns a view of the portion of this sorted set whose elements are greater than or equal to fromElement.
 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.objects.AbstractObjectSortedSet
objectIterator
 
Methods inherited from class it.unimi.dsi.fastutil.objects.AbstractObjectSet
equals
 
Methods inherited from class it.unimi.dsi.fastutil.objects.AbstractObjectCollection
addAll, containsAll, removeAll, retainAll, toArray, toArray, toString
 
Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface it.unimi.dsi.fastutil.objects.ObjectCollection
toArray
 
Methods inherited from interface java.util.Set
addAll, containsAll, equals, removeAll, retainAll, toArray, toArray
 
Methods inherited from interface java.util.Set
addAll, containsAll, equals, removeAll, retainAll, toArray, toArray
 

Field Detail

serialVersionUID

public static final long serialVersionUID
See Also:
Constant Field Values
Constructor Detail

ObjectLinkedOpenCustomHashSet

public ObjectLinkedOpenCustomHashSet(int n,
                                     float f,
                                     Hash.Strategy<K> strategy)
Creates a new hash set. The actual table size is the least available prime greater than n/f.

Parameters:
n - the expected number of elements in the hash set.
f - the load factor.
strategy - the strategy.
See Also:
Hash.PRIMES

ObjectLinkedOpenCustomHashSet

public ObjectLinkedOpenCustomHashSet(int n,
                                     Hash.Strategy<K> strategy)
Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor.

Parameters:
n - the expected number of elements in the hash set.
strategy - the strategy.

ObjectLinkedOpenCustomHashSet

public ObjectLinkedOpenCustomHashSet(Hash.Strategy<K> strategy)
Creates a new hash set with Hash.DEFAULT_INITIAL_SIZE elements and Hash.DEFAULT_LOAD_FACTOR as load factor.

Parameters:
strategy - the strategy.

ObjectLinkedOpenCustomHashSet

public ObjectLinkedOpenCustomHashSet(java.util.Collection<? extends K> c,
                                     float f,
                                     Hash.Strategy<K> 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.

ObjectLinkedOpenCustomHashSet

public ObjectLinkedOpenCustomHashSet(java.util.Collection<? extends K> c,
                                     Hash.Strategy<K> 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.

ObjectLinkedOpenCustomHashSet

public ObjectLinkedOpenCustomHashSet(ObjectCollection<? extends K> c,
                                     float f,
                                     Hash.Strategy<K> 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.

ObjectLinkedOpenCustomHashSet

public ObjectLinkedOpenCustomHashSet(ObjectCollection<? extends K> c,
                                     Hash.Strategy<K> 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.

ObjectLinkedOpenCustomHashSet

public ObjectLinkedOpenCustomHashSet(ObjectIterator<K> i,
                                     float f,
                                     Hash.Strategy<K> 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.

ObjectLinkedOpenCustomHashSet

public ObjectLinkedOpenCustomHashSet(ObjectIterator<K> i,
                                     Hash.Strategy<K> 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.

ObjectLinkedOpenCustomHashSet

public ObjectLinkedOpenCustomHashSet(K[] a,
                                     int offset,
                                     int length,
                                     float f,
                                     Hash.Strategy<K> 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.

ObjectLinkedOpenCustomHashSet

public ObjectLinkedOpenCustomHashSet(K[] a,
                                     int offset,
                                     int length,
                                     Hash.Strategy<K> 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.

ObjectLinkedOpenCustomHashSet

public ObjectLinkedOpenCustomHashSet(K[] a,
                                     float f,
                                     Hash.Strategy<K> 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.

ObjectLinkedOpenCustomHashSet

public ObjectLinkedOpenCustomHashSet(K[] a,
                                     Hash.Strategy<K> 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 Hash.Strategy<K> strategy()
Returns the hashing strategy.

Returns:
the hashing strategy of this custom hash set.

growthFactor

public void growthFactor(int growthFactor)
Sets the growth factor. Subsequent enlargements will increase the table size roughly by a multiplicative factor of 2p/16.

Parameters:
growthFactor - the new growth factor; it must be positive.

growthFactor

public int growthFactor()
Gets the growth factor.

Returns:
the growth factor of this set.
See Also:
growthFactor(int)

add

public boolean add(K k)
Specified by:
add in interface java.util.Collection<K>
Specified by:
add in interface java.util.Set<K>
Overrides:
add in class AbstractObjectCollection<K>

remove

public boolean remove(java.lang.Object k)
Description copied from interface: ObjectSet
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 ObjectSet<K>
Specified by:
remove in interface java.util.Collection<K>
Specified by:
remove in interface java.util.Set<K>
Overrides:
remove in class AbstractObjectSet<K>
See Also:
Collection.remove(Object)

contains

public boolean contains(java.lang.Object k)
Specified by:
contains in interface java.util.Collection<K>
Specified by:
contains in interface java.util.Set<K>

clear

public void clear()
Specified by:
clear in interface java.util.Collection<K>
Specified by:
clear in interface java.util.Set<K>
Overrides:
clear in class AbstractObjectCollection<K>

first

public K first()
Returns the first element of this set in iteration order.

Specified by:
first in interface java.util.SortedSet<K>
Returns:
the first element in iteration order.

last

public K last()
Returns the last element of this set in iteration order.

Specified by:
last in interface java.util.SortedSet<K>
Returns:
the last element in iteration order.

tailSet

public ObjectSortedSet<K> tailSet(K from)
Description copied from interface: ObjectSortedSet
Returns a view of the portion of this sorted set whose elements are greater than or equal to fromElement.

Note that this specification strengthens the one given in SortedSet.tailSet(Object).

Specified by:
tailSet in interface ObjectSortedSet<K>
Specified by:
tailSet in interface java.util.SortedSet<K>
See Also:
SortedSet.tailSet(Object)

headSet

public ObjectSortedSet<K> headSet(K to)
Description copied from interface: ObjectSortedSet
Returns a view of the portion of this sorted set whose elements are strictly less than toElement.

Note that this specification strengthens the one given in SortedSet.headSet(Object).

Specified by:
headSet in interface ObjectSortedSet<K>
Specified by:
headSet in interface java.util.SortedSet<K>
See Also:
SortedSet.headSet(Object)

subSet

public ObjectSortedSet<K> subSet(K from,
                                 K to)
Description copied from interface: ObjectSortedSet
Returns a view of the portion of this sorted set whose elements range from fromElement, inclusive, to toElement, exclusive.

Note that this specification strengthens the one given in SortedSet.subSet(Object,Object).

Specified by:
subSet in interface ObjectSortedSet<K>
Specified by:
subSet in interface java.util.SortedSet<K>
See Also:
SortedSet.subSet(Object,Object)

comparator

public java.util.Comparator<? super K> comparator()
Specified by:
comparator in interface java.util.SortedSet<K>

iterator

public ObjectBidirectionalIterator<K> iterator(K from)
Returns a type-specific list iterator on the elements in this set, starting from a given element of the set.

This method provides an iterator positioned immediately after the given element. That is, the next call to previous() will return from, whereas the next call to next() will return the element immediately after from. This allows to call iterator(last()) and obtain an iterator starting from the end of the iteration order.

Because of the way linking is implemented, generating an iterator using this method requires constant time only if the argument is last(). In all other cases, a linear search for the given element will be necessary.

Note that this method returns a bidirectional iterator, which, however, can be safely cast to a type-specific list iterator.

Specified by:
iterator in interface ObjectSortedSet<K>
Parameters:
from - an element to start from.
Returns:
a type-specific list iterator starting at the given element.
Throws:
java.lang.IllegalArgumentException - if from does not belong to the set.

iterator

public ObjectBidirectionalIterator<K> iterator()
Description copied from interface: ObjectCollection
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 ObjectCollection<K>
Specified by:
iterator in interface ObjectIterable<K>
Specified by:
iterator in interface ObjectSet<K>
Specified by:
iterator in interface ObjectSortedSet<K>
Specified by:
iterator in interface java.lang.Iterable<K>
Specified by:
iterator in interface java.util.Collection<K>
Specified by:
iterator in interface java.util.Set<K>
Specified by:
iterator in class AbstractObjectSortedSet<K>
Returns:
a type-specific iterator on the elements of this collection.

rehash

public boolean rehash()
Rehashes this set without changing the table size.

This method should be called when the set underwent numerous deletions and insertions. In this case, free entries become rare, and unsuccessful searches require probing all entries. For reasonable load factors this method is linear in the number of entries. You will need as much additional free memory as that occupied by the table.

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

Returns:
true if there was enough memory to rehash the set, false otherwise.
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 (by collecting deleted entries) and size.

If the table size is already the minimum possible, this method does nothing. If you want to guarantee rehashing, use rehash().

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

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(), rehash()

size

public int size()
Specified by:
size in interface java.util.Collection<K>
Specified by:
size in interface java.util.Set<K>

isEmpty

public boolean isEmpty()
Specified by:
isEmpty in interface java.util.Collection<K>
Specified by:
isEmpty in interface java.util.Set<K>
Overrides:
isEmpty in class AbstractObjectCollection<K>

clone

public java.lang.Object 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<K>
Specified by:
hashCode in interface java.util.Set<K>
Overrides:
hashCode in class AbstractObjectSet<K>
Returns:
a hash code for this set.