it.unimi.dsi.fastutil.bytes
Class ByteLinkedOpenHashSet

java.lang.Object
  extended by java.util.AbstractCollection<java.lang.Byte>
      extended by it.unimi.dsi.fastutil.bytes.AbstractByteCollection
          extended by it.unimi.dsi.fastutil.bytes.AbstractByteSet
              extended by it.unimi.dsi.fastutil.bytes.AbstractByteSortedSet
                  extended by it.unimi.dsi.fastutil.bytes.ByteLinkedOpenHashSet
All Implemented Interfaces:
ByteCollection, ByteIterable, ByteSet, ByteSortedSet, Hash, java.io.Serializable, java.lang.Cloneable, java.lang.Iterable<java.lang.Byte>, java.util.Collection<java.lang.Byte>, java.util.Set<java.lang.Byte>, java.util.SortedSet<java.lang.Byte>

public class ByteLinkedOpenHashSet
extends AbstractByteSortedSet
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 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.

Iterators generated by this set will enumerate elements in the same order in which they have been added to the set (addition of elements already present in the set does not change the iteration order). Note that this order has nothing in common with the natural order of the keys. The order is kept by means of a doubly linked list, represented via an array of longs parallel to the table.

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 AbstractByteSortedSet.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.

Additional methods, such as addAndMoveToFirst(), make it easy to use instances of this class as a cache (e.g., with LRU policy).

The iterators provided by this class are type-specific list iterators, and can be started at any element which is in the set (if the provided element is not in the set, a NoSuchElementException exception will be thrown). If, however, the provided element is not the first or last element in the set, the first access to the list index will require linear time, as in the worst case the entire set must be scanned in iteration order to retrieve the positional index of the starting element. If you use just the methods of a type-specific BidirectionalIterator, however, all operations will be performed in constant time.

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
ByteLinkedOpenHashSet()
          Creates a new hash set with initial expected Hash.DEFAULT_INITIAL_SIZE elements and Hash.DEFAULT_LOAD_FACTOR as load factor.
ByteLinkedOpenHashSet(byte[] a)
          Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor copying the elements of an array.
ByteLinkedOpenHashSet(byte[] a, float f)
          Creates a new hash set copying the elements of an array.
ByteLinkedOpenHashSet(byte[] 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.
ByteLinkedOpenHashSet(byte[] a, int offset, int length, float f)
          Creates a new hash set and fills it with the elements of a given array.
ByteLinkedOpenHashSet(ByteCollection c)
          Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific collection.
ByteLinkedOpenHashSet(ByteCollection c, float f)
          Creates a new hash set copying a given type-specific collection.
ByteLinkedOpenHashSet(ByteIterator i)
          Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor using elements provided by a type-specific iterator.
ByteLinkedOpenHashSet(ByteIterator i, float f)
          Creates a new hash set using elements provided by a type-specific iterator.
ByteLinkedOpenHashSet(java.util.Collection<? extends java.lang.Byte> c)
          Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given collection.
ByteLinkedOpenHashSet(java.util.Collection<? extends java.lang.Byte> c, float f)
          Creates a new hash set copying a given collection.
ByteLinkedOpenHashSet(int expected)
          Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor.
ByteLinkedOpenHashSet(int expected, float f)
          Creates a new hash set.
ByteLinkedOpenHashSet(java.util.Iterator<?> i)
          Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor using elements provided by an iterator.
ByteLinkedOpenHashSet(java.util.Iterator<?> i, float f)
          Creates a new hash set using elements provided by an iterator.
 
Method Summary
 boolean add(byte k)
           
 boolean addAndMoveToFirst(byte k)
          Adds a key to the set; if the key is already present, it is moved to the first position of the iteration order.
 boolean addAndMoveToLast(byte k)
          Adds a key to the set; if the key is already present, it is moved to the last position of the iteration order.
 void clear()
           
 ByteLinkedOpenHashSet clone()
          Returns a deep copy of this set.
 ByteComparator comparator()
          Returns the comparator associated with this sorted set, or null if it uses its elements' natural ordering.
 boolean contains(byte k)
           
 byte firstByte()
          Returns the first element of this set in iteration order.
 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.
 ByteSortedSet headSet(byte to)
           
 boolean isEmpty()
           
 ByteListIterator iterator()
          Returns a type-specific iterator on the elements of this collection.
 ByteListIterator iterator(byte from)
          Returns a type-specific list iterator on the elements in this set, starting from a given element of the set.
 byte lastByte()
          Returns the last element of this set in iteration order.
 boolean rehash()
          Deprecated. A no-op.
 boolean remove(byte k)
          Removes an element from this set.
 byte removeFirstByte()
          Removes the first key in iteration order.
 byte removeLastByte()
          Removes the the last key in iteration order.
 int size()
           
 ByteSortedSet subSet(byte from, byte to)
           
 ByteSortedSet tailSet(byte from)
           
 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.bytes.AbstractByteSortedSet
byteIterator, first, headSet, last, subSet, tailSet
 
Methods inherited from class it.unimi.dsi.fastutil.bytes.AbstractByteSet
equals, rem, remove
 
Methods inherited from class it.unimi.dsi.fastutil.bytes.AbstractByteCollection
add, addAll, addAll, contains, containsAll, containsAll, rem, removeAll, removeAll, retainAll, retainAll, toArray, toArray, toArray, toByteArray, toByteArray, toString
 
Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface it.unimi.dsi.fastutil.bytes.ByteCollection
addAll, containsAll, rem, removeAll, retainAll, toArray, toArray, toByteArray, toByteArray
 
Methods inherited from interface java.util.Set
add, addAll, contains, containsAll, equals, remove, removeAll, retainAll, toArray, toArray
 

Constructor Detail

ByteLinkedOpenHashSet

public ByteLinkedOpenHashSet(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.

ByteLinkedOpenHashSet

public ByteLinkedOpenHashSet(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.

ByteLinkedOpenHashSet

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


ByteLinkedOpenHashSet

public ByteLinkedOpenHashSet(java.util.Collection<? extends java.lang.Byte> 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.

ByteLinkedOpenHashSet

public ByteLinkedOpenHashSet(java.util.Collection<? extends java.lang.Byte> 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.

ByteLinkedOpenHashSet

public ByteLinkedOpenHashSet(ByteCollection 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.

ByteLinkedOpenHashSet

public ByteLinkedOpenHashSet(ByteCollection 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.

ByteLinkedOpenHashSet

public ByteLinkedOpenHashSet(ByteIterator 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.

ByteLinkedOpenHashSet

public ByteLinkedOpenHashSet(ByteIterator 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.

ByteLinkedOpenHashSet

public ByteLinkedOpenHashSet(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.

ByteLinkedOpenHashSet

public ByteLinkedOpenHashSet(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.

ByteLinkedOpenHashSet

public ByteLinkedOpenHashSet(byte[] 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.

ByteLinkedOpenHashSet

public ByteLinkedOpenHashSet(byte[] 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.

ByteLinkedOpenHashSet

public ByteLinkedOpenHashSet(byte[] 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.

ByteLinkedOpenHashSet

public ByteLinkedOpenHashSet(byte[] 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

add

public boolean add(byte k)
Specified by:
add in interface ByteCollection
Overrides:
add in class AbstractByteCollection
See Also:
Collection.add(Object)

remove

public boolean remove(byte k)
Description copied from interface: ByteSet
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 ByteSet
Overrides:
remove in class AbstractByteSet
See Also:
Collection.remove(Object)

contains

public boolean contains(byte k)
Specified by:
contains in interface ByteCollection
Overrides:
contains in class AbstractByteCollection
See Also:
Collection.contains(Object)

removeFirstByte

public byte removeFirstByte()
Removes the first key in iteration order.

Returns:
the first key.
Throws:
java.util.NoSuchElementException - is this set is empty.

removeLastByte

public byte removeLastByte()
Removes the the last key in iteration order.

Returns:
the last key.
Throws:
java.util.NoSuchElementException - is this set is empty.

addAndMoveToFirst

public boolean addAndMoveToFirst(byte k)
Adds a key to the set; if the key is already present, it is moved to the first position of the iteration order.

Parameters:
k - the key.
Returns:
true if the key was not present.

addAndMoveToLast

public boolean addAndMoveToLast(byte k)
Adds a key to the set; if the key is already present, it is moved to the last position of the iteration order.

Parameters:
k - the key.
Returns:
true if the key was not present.

clear

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

size

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

isEmpty

public boolean isEmpty()
Specified by:
isEmpty in interface java.util.Collection<java.lang.Byte>
Specified by:
isEmpty in interface java.util.Set<java.lang.Byte>
Overrides:
isEmpty in class AbstractByteCollection

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)

firstByte

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

Specified by:
firstByte in interface ByteSortedSet
Returns:
the first element in iteration order.
See Also:
SortedSet.first()

lastByte

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

Specified by:
lastByte in interface ByteSortedSet
Returns:
the last element in iteration order.
See Also:
SortedSet.last()

tailSet

public ByteSortedSet tailSet(byte from)
Specified by:
tailSet in interface ByteSortedSet
See Also:
SortedSet.tailSet(Object)

headSet

public ByteSortedSet headSet(byte to)
Specified by:
headSet in interface ByteSortedSet
See Also:
SortedSet.headSet(Object)

subSet

public ByteSortedSet subSet(byte from,
                            byte to)
Specified by:
subSet in interface ByteSortedSet
See Also:
SortedSet.subSet(Object,Object)

comparator

public ByteComparator comparator()
Description copied from interface: ByteSortedSet
Returns the comparator associated with this sorted set, or null if it uses its elements' natural ordering.

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

Specified by:
comparator in interface ByteSortedSet
Specified by:
comparator in interface java.util.SortedSet<java.lang.Byte>
See Also:
SortedSet.comparator()

iterator

public ByteListIterator iterator(byte from)
Returns a type-specific list iterator on the elements in this set, starting from a given element of the set. Please see the class documentation for implementation details.

Specified by:
iterator in interface ByteSortedSet
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 ByteListIterator iterator()
Description copied from interface: ByteCollection
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 ByteCollection
Specified by:
iterator in interface ByteIterable
Specified by:
iterator in interface ByteSet
Specified by:
iterator in interface ByteSortedSet
Specified by:
iterator in interface java.lang.Iterable<java.lang.Byte>
Specified by:
iterator in interface java.util.Collection<java.lang.Byte>
Specified by:
iterator in interface java.util.Set<java.lang.Byte>
Specified by:
iterator in class AbstractByteSortedSet
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 ByteLinkedOpenHashSet 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.Byte>
Specified by:
hashCode in interface java.util.Set<java.lang.Byte>
Overrides:
hashCode in class AbstractByteSet
Returns:
a hash code for this set.