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java.lang.Objectit.unimi.dsi.fastutil.objects.AbstractObjectCollection<K>
it.unimi.dsi.fastutil.objects.AbstractObjectSet<K>
it.unimi.dsi.fastutil.objects.ObjectOpenCustomHashSet<K>
public class ObjectOpenCustomHashSet<K>
A hash set with 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 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).
Hash
,
HashCommon
,
Serialized FormNested 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 | |
---|---|
ObjectOpenCustomHashSet(java.util.Collection<? extends K> c,
float f,
Hash.Strategy<K> strategy)
Creates a new hash set copying a given collection. |
|
ObjectOpenCustomHashSet(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. |
|
ObjectOpenCustomHashSet(Hash.Strategy<K> strategy)
Creates a new hash set with Hash.DEFAULT_INITIAL_SIZE elements
and Hash.DEFAULT_LOAD_FACTOR as load factor. |
|
ObjectOpenCustomHashSet(int n,
float f,
Hash.Strategy<K> strategy)
Creates a new hash set. |
|
ObjectOpenCustomHashSet(int n,
Hash.Strategy<K> strategy)
Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor. |
|
ObjectOpenCustomHashSet(K[] a,
float f,
Hash.Strategy<K> strategy)
Creates a new hash set copying the elements of an array. |
|
ObjectOpenCustomHashSet(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. |
|
ObjectOpenCustomHashSet(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. |
|
ObjectOpenCustomHashSet(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. |
|
ObjectOpenCustomHashSet(ObjectCollection<? extends K> c,
float f,
Hash.Strategy<K> strategy)
Creates a new hash set copying a given type-specific collection. |
|
ObjectOpenCustomHashSet(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. |
|
ObjectOpenCustomHashSet(ObjectIterator<K> i,
float f,
Hash.Strategy<K> strategy)
Creates a new hash set using elements provided by a type-specific iterator. |
|
ObjectOpenCustomHashSet(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. |
boolean |
contains(java.lang.Object k)
|
int |
growthFactor()
Gets the growth factor. |
void |
growthFactor(int growthFactor)
Sets the growth factor. |
int |
hashCode()
Returns a hash code for this set. |
boolean |
isEmpty()
|
ObjectIterator<K> |
iterator()
Returns a type-specific iterator on the elements of this collection. |
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. |
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.AbstractObjectSet |
---|
equals |
Methods inherited from class it.unimi.dsi.fastutil.objects.AbstractObjectCollection |
---|
addAll, containsAll, objectIterator, 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 |
---|
objectIterator, toArray |
Methods inherited from interface java.util.Set |
---|
addAll, containsAll, removeAll, retainAll, toArray, toArray |
Field Detail |
---|
public static final long serialVersionUID
Constructor Detail |
---|
public ObjectOpenCustomHashSet(int n, float f, Hash.Strategy<K> strategy)
n
/f
.
n
- the expected number of elements in the hash set.f
- the load factor.strategy
- the strategy.Hash.PRIMES
public ObjectOpenCustomHashSet(int n, Hash.Strategy<K> strategy)
Hash.DEFAULT_LOAD_FACTOR
as load factor.
n
- the expected number of elements in the hash set.strategy
- the strategy.public ObjectOpenCustomHashSet(Hash.Strategy<K> strategy)
Hash.DEFAULT_INITIAL_SIZE
elements
and Hash.DEFAULT_LOAD_FACTOR
as load factor.
strategy
- the strategy.public ObjectOpenCustomHashSet(java.util.Collection<? extends K> c, float f, Hash.Strategy<K> strategy)
c
- a Collection
to be copied into the new hash set.f
- the load factor.strategy
- the strategy.public ObjectOpenCustomHashSet(java.util.Collection<? extends K> c, Hash.Strategy<K> strategy)
Hash.DEFAULT_LOAD_FACTOR
as load factor
copying a given collection.
c
- a Collection
to be copied into the new hash set.strategy
- the strategy.public ObjectOpenCustomHashSet(ObjectCollection<? extends K> c, float f, Hash.Strategy<K> strategy)
c
- a type-specific collection to be copied into the new hash set.f
- the load factor.strategy
- the strategy.public ObjectOpenCustomHashSet(ObjectCollection<? extends K> c, Hash.Strategy<K> strategy)
Hash.DEFAULT_LOAD_FACTOR
as load factor
copying a given type-specific collection.
c
- a type-specific collection to be copied into the new hash set.strategy
- the strategy.public ObjectOpenCustomHashSet(ObjectIterator<K> i, float f, Hash.Strategy<K> strategy)
i
- a type-specific iterator whose elements will fill the set.f
- the load factor.strategy
- the strategy.public ObjectOpenCustomHashSet(ObjectIterator<K> i, Hash.Strategy<K> strategy)
Hash.DEFAULT_LOAD_FACTOR
as load factor using elements provided by a type-specific iterator.
i
- a type-specific iterator whose elements will fill the set.strategy
- the strategy.public ObjectOpenCustomHashSet(K[] a, int offset, int length, float f, Hash.Strategy<K> strategy)
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.public ObjectOpenCustomHashSet(K[] a, int offset, int length, Hash.Strategy<K> strategy)
Hash.DEFAULT_LOAD_FACTOR
as load factor and fills it with the elements of a given array.
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.public ObjectOpenCustomHashSet(K[] a, float f, Hash.Strategy<K> strategy)
a
- an array to be copied into the new hash set.f
- the load factor.strategy
- the strategy.public ObjectOpenCustomHashSet(K[] a, Hash.Strategy<K> strategy)
Hash.DEFAULT_LOAD_FACTOR
as load factor
copying the elements of an array.
a
- an array to be copied into the new hash set.strategy
- the strategy.Method Detail |
---|
public Hash.Strategy<K> strategy()
public void growthFactor(int growthFactor)
growthFactor
- the new growth factor; it must be positive.public int growthFactor()
growthFactor(int)
public boolean add(K k)
add
in interface java.util.Collection<K>
add
in interface java.util.Set<K>
add
in class AbstractObjectCollection<K>
public boolean remove(java.lang.Object k)
ObjectSet
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.
remove
in interface ObjectSet<K>
remove
in interface java.util.Collection<K>
remove
in interface java.util.Set<K>
remove
in class AbstractObjectSet<K>
Collection.remove(Object)
public boolean contains(java.lang.Object k)
contains
in interface java.util.Collection<K>
contains
in interface java.util.Set<K>
public void clear()
clear
in interface java.util.Collection<K>
clear
in interface java.util.Set<K>
clear
in class AbstractObjectCollection<K>
public ObjectIterator<K> iterator()
ObjectCollection
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
.
iterator
in interface ObjectCollection<K>
iterator
in interface ObjectIterable<K>
iterator
in interface ObjectSet<K>
iterator
in interface java.lang.Iterable<K>
iterator
in interface java.util.Collection<K>
iterator
in interface java.util.Set<K>
iterator
in class AbstractObjectSet<K>
public boolean rehash()
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()
.
trim()
public boolean trim()
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()
.
trim(int)
,
rehash()
public boolean trim(int n)
Let N be the smallest table size that can hold
max(n,
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.
size()
)
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.
n
- the threshold for the trimming.
trim()
,
rehash()
public int size()
size
in interface java.util.Collection<K>
size
in interface java.util.Set<K>
public boolean isEmpty()
isEmpty
in interface java.util.Collection<K>
isEmpty
in interface java.util.Set<K>
isEmpty
in class AbstractObjectCollection<K>
public java.lang.Object clone()
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.
clone
in class java.lang.Object
public int hashCode()
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.
hashCode
in interface java.util.Collection<K>
hashCode
in interface java.util.Set<K>
hashCode
in class AbstractObjectSet<K>
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