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

java.lang.Object
  extended by java.util.AbstractCollection<K>
      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.ObjectOpenHashBigSet<K>
All Implemented Interfaces:
Hash, ObjectCollection<K>, ObjectIterable<K>, ObjectSet<K>, Size64, Serializable, Cloneable, Iterable<K>, Collection<K>, Set<K>

public class ObjectOpenHashBigSet<K>
extends AbstractObjectSet<K>
implements Serializable, Cloneable, Hash, Size64

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

Instances of this class use a hash table to represent a big set: the number of elements in the set is limited only by the amount of core memory. The table is backed by a big array and 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 method lets you control the size of the table; this is particularly useful if you reuse instances of this class.

The methods of this class are about 30% slower than those of the corresponding non-big set.

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
ObjectOpenHashBigSet()
          Creates a new hash big set with initial expected Hash.DEFAULT_INITIAL_SIZE elements and Hash.DEFAULT_LOAD_FACTOR as load factor.
ObjectOpenHashBigSet(Collection<? extends K> c)
          Creates a new hash big set with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given collection.
ObjectOpenHashBigSet(Collection<? extends K> c, float f)
          Creates a new hash big set copying a given collection.
ObjectOpenHashBigSet(K[] a)
          Creates a new hash big set with Hash.DEFAULT_LOAD_FACTOR as load factor copying the elements of an array.
ObjectOpenHashBigSet(K[] a, float f)
          Creates a new hash big set copying the elements of an array.
ObjectOpenHashBigSet(K[] a, int offset, int length)
          Creates a new hash big set with Hash.DEFAULT_LOAD_FACTOR as load factor and fills it with the elements of a given array.
ObjectOpenHashBigSet(K[] a, int offset, int length, float f)
          Creates a new hash big set and fills it with the elements of a given array.
ObjectOpenHashBigSet(long expected)
          Creates a new hash big set with Hash.DEFAULT_LOAD_FACTOR as load factor.
ObjectOpenHashBigSet(long expected, float f)
          Creates a new hash big set.
ObjectOpenHashBigSet(ObjectCollection<? extends K> c)
          Creates a new hash big set with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific collection.
ObjectOpenHashBigSet(ObjectCollection<? extends K> c, float f)
          Creates a new hash big set copying a given type-specific collection.
ObjectOpenHashBigSet(ObjectIterator<K> i)
          Creates a new hash big set with Hash.DEFAULT_LOAD_FACTOR as load factor using elements provided by a type-specific iterator.
ObjectOpenHashBigSet(ObjectIterator<K> i, float f)
          Creates a new hash big set using elements provided by a type-specific iterator.
 
Method Summary
 boolean add(K k)
           
 void clear()
           
 ObjectOpenHashBigSet<K> clone()
          Returns a deep copy of this big set.
 boolean contains(Object k)
           
 K get(Object k)
          Returns the element of this set that is equal to the given key, or null.
 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()
          Deprecated. A no-op.
 boolean remove(Object k)
          Removes an element from this set.
 int size()
          Deprecated. 
 long size64()
          Returns the size of this data structure as a long.
 boolean trim()
          Rehashes this set, making the table as small as possible.
 boolean trim(long 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

serialVersionUID

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

ObjectOpenHashBigSet

public ObjectOpenHashBigSet(long expected,
                            float f)
Creates a new hash big 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 set.
f - the load factor.

ObjectOpenHashBigSet

public ObjectOpenHashBigSet(long expected)
Creates a new hash big set with Hash.DEFAULT_LOAD_FACTOR as load factor.

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

ObjectOpenHashBigSet

public ObjectOpenHashBigSet()
Creates a new hash big set with initial expected Hash.DEFAULT_INITIAL_SIZE elements and Hash.DEFAULT_LOAD_FACTOR as load factor.


ObjectOpenHashBigSet

public ObjectOpenHashBigSet(Collection<? extends K> c,
                            float f)
Creates a new hash big set copying a given collection.

Parameters:
c - a Collection to be copied into the new hash big set.
f - the load factor.

ObjectOpenHashBigSet

public ObjectOpenHashBigSet(Collection<? extends K> c)
Creates a new hash big set with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given collection.

Parameters:
c - a Collection to be copied into the new hash big set.

ObjectOpenHashBigSet

public ObjectOpenHashBigSet(ObjectCollection<? extends K> c,
                            float f)
Creates a new hash big set copying a given type-specific collection.

Parameters:
c - a type-specific collection to be copied into the new hash big set.
f - the load factor.

ObjectOpenHashBigSet

public ObjectOpenHashBigSet(ObjectCollection<? extends K> c)
Creates a new hash big 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 big set.

ObjectOpenHashBigSet

public ObjectOpenHashBigSet(ObjectIterator<K> i,
                            float f)
Creates a new hash big set using elements provided by a type-specific iterator.

Parameters:
i - a type-specific iterator whose elements will fill the new hash big set.
f - the load factor.

ObjectOpenHashBigSet

public ObjectOpenHashBigSet(ObjectIterator<K> i)
Creates a new hash big 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 new hash big set.

ObjectOpenHashBigSet

public ObjectOpenHashBigSet(K[] a,
                            int offset,
                            int length,
                            float f)
Creates a new hash big set and fills it with the elements of a given array.

Parameters:
a - an array whose elements will be used to fill the new hash big set.
offset - the first element to use.
length - the number of elements to use.
f - the load factor.

ObjectOpenHashBigSet

public ObjectOpenHashBigSet(K[] a,
                            int offset,
                            int length)
Creates a new hash big 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 new hash big set.
offset - the first element to use.
length - the number of elements to use.

ObjectOpenHashBigSet

public ObjectOpenHashBigSet(K[] a,
                            float f)
Creates a new hash big set copying the elements of an array.

Parameters:
a - an array to be copied into the new hash big set.
f - the load factor.

ObjectOpenHashBigSet

public ObjectOpenHashBigSet(K[] a)
Creates a new hash big 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 big set.
Method Detail

add

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

remove

public boolean remove(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 Collection<K>
Specified by:
remove in interface Set<K>
Overrides:
remove in class AbstractObjectSet<K>
See Also:
Collection.remove(Object)

contains

public boolean contains(Object k)
Specified by:
contains in interface Collection<K>
Specified by:
contains in interface Set<K>
Overrides:
contains in class AbstractCollection<K>

get

public K get(Object k)
Returns the element of this set that is equal to the given key, or null.

Returns:
the element of this set that is equal to the given key, or null.

clear

public void clear()
Specified by:
clear in interface Collection<K>
Specified by:
clear in interface Set<K>
Overrides:
clear in class AbstractCollection<K>

iterator

public ObjectIterator<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 Iterable<K>
Specified by:
iterator in interface Collection<K>
Specified by:
iterator in interface Set<K>
Specified by:
iterator in class AbstractObjectSet<K>
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(long)

trim

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

Let N be the smallest table size that can hold max(n,size64()) 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()

size

@Deprecated
public int size()
Deprecated. 

Description copied from interface: Size64
Returns the size of this data structure, minimized with Integer.MAX_VALUE.

Specified by:
size in interface Size64
Specified by:
size in interface Collection<K>
Specified by:
size in interface Set<K>
Specified by:
size in class AbstractCollection<K>
Returns:
the size of this data structure, minimized with Integer.MAX_VALUE.
See Also:
Collection.size()

size64

public long size64()
Description copied from interface: Size64
Returns the size of this data structure as a long.

Specified by:
size64 in interface Size64
Returns:
the size of this data structure.

isEmpty

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

clone

public ObjectOpenHashBigSet<K> clone()
Returns a deep copy of this big set.

This method performs a deep copy of this big 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 Object
Returns:
a deep copy of this big 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 Collection<K>
Specified by:
hashCode in interface Set<K>
Overrides:
hashCode in class AbstractObjectSet<K>
Returns:
a hash code for this set.