fabric.common.util
Class LongHashSet

java.lang.Object
  fabric.common.util.AbstractLongCollection
      fabric.common.util.AbstractLongSet
          fabric.common.util.LongHashSet

All Implemented Interfaces:

LongCollection, LongIterable, LongSet

public class LongHashSet
extends AbstractLongSet
implements LongSet

This class provides a HashMap-backed implementation of the Set interface.

Most operations are O(1), assuming no hash collisions. In the worst case (where all hashes collide), operations are O(n). Setting the initial capacity too low will force many resizing operations, but setting the initial capacity too high (or loadfactor too low) leads to wasted memory and slower iteration.

HashSet accepts the null key and null values. It is not synchronized, so if you need multi-threaded access, consider using:
Set s = Collections.synchronizedSet(new HashSet(...));

The iterators are fail-fast, meaning that any structural modification, except for remove() called on the iterator itself, cause the iterator to throw a ConcurrentModificationException rather than exhibit non-deterministic behavior.

Since:

1.2

Author:

Jon Zeppieri, Eric Blake (ebb9@email.byu.edu)

See Also:

LongCollection, LongSet, LongKeyHashMap

Constructor Summary

LongHashSet()
Construct a new, empty HashSet whose backing HashMap has the default capacity (11) and loadFacor (0.75).

LongHashSet(int initialCapacity)
Construct a new, empty HashSet whose backing HashMap has the supplied capacity and the default load factor (0.75).

LongHashSet(int initialCapacity, float loadFactor)
Construct a new, empty HashSet whose backing HashMap has the supplied capacity and load factor.

LongHashSet(LongCollection c)
Construct a new HashSet with the same elements as are in the supplied collection (eliminating any duplicates, of course).

Method Summary

boolean	add(long v) Adds the given Object to the set if it is not already in the Set.
void	clear() Empties this Set of all elements; this takes constant time.
boolean	contains(long v) Returns true if the supplied element is in this Set.
boolean	isEmpty() Returns true if this set has no elements in it.
LongIterator	iterator() Returns an Iterator over the elements of this Set, which visits the elements in no particular order.
boolean	remove(long v) Removes the supplied Object from this Set if it is in the Set.
int	size() Returns the number of elements in this Set (its cardinality).

Methods inherited from class fabric.common.util.AbstractLongSet

equals, hashCode, removeAll

Methods inherited from class fabric.common.util.AbstractLongCollection

addAll, containsAll, retainAll, toArray, toArray, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface fabric.common.util.LongSet

addAll, containsAll, equals, hashCode, removeAll, retainAll, toArray, toArray

Constructor Detail

LongHashSet

public LongHashSet()

Construct a new, empty HashSet whose backing HashMap has the default capacity (11) and loadFacor (0.75).

LongHashSet

public LongHashSet(int initialCapacity)

Construct a new, empty HashSet whose backing HashMap has the supplied capacity and the default load factor (0.75).

Parameters:

initialCapacity - the initial capacity of the backing HashMap

Throws:

java.lang.IllegalArgumentException - if the capacity is negative

LongHashSet

public LongHashSet(int initialCapacity,
                   float loadFactor)

Construct a new, empty HashSet whose backing HashMap has the supplied capacity and load factor.

Parameters:

initialCapacity - the initial capacity of the backing HashMap

loadFactor - the load factor of the backing HashMap

Throws:

java.lang.IllegalArgumentException - if either argument is negative, or if loadFactor is POSITIVE_INFINITY or NaN

LongHashSet

public LongHashSet(LongCollection c)

Construct a new HashSet with the same elements as are in the supplied collection (eliminating any duplicates, of course). The backing storage has twice the size of the collection, or the default size of 11, whichever is greater; and the default load factor (0.75).

Parameters:

c - a collection of initial set elements

Throws:

java.lang.NullPointerException - if c is null

Method Detail

add

public boolean add(long v)

Adds the given Object to the set if it is not already in the Set. This set permits a null element.

Specified by:

add in interface LongCollection

Specified by:

add in interface LongSet

Overrides:

add in class AbstractLongCollection

Parameters:

v - the Object to add to this Set

Returns:

true if the set did not already contain v

clear

public void clear()

Empties this Set of all elements; this takes constant time.

Specified by:

clear in interface LongCollection

Specified by:

clear in interface LongSet

Overrides:

clear in class AbstractLongCollection

See Also:

LongIterator.remove()

contains

public boolean contains(long v)

Returns true if the supplied element is in this Set.

Specified by:

contains in interface LongCollection

Specified by:

contains in interface LongSet

Overrides:

contains in class AbstractLongCollection

Parameters:

v - the long to look for

Returns:

true if v is in the set

isEmpty

public boolean isEmpty()

Returns true if this set has no elements in it.

Specified by:

isEmpty in interface LongCollection

Specified by:

isEmpty in interface LongSet

Overrides:

isEmpty in class AbstractLongCollection

Returns:

size() == 0.

See Also:

AbstractLongCollection.size()

iterator

public LongIterator iterator()

Returns an Iterator over the elements of this Set, which visits the elements in no particular order. For this class, the Iterator allows removal of elements. The iterator is fail-fast, and will throw a ConcurrentModificationException if the set is modified externally.

Specified by:

iterator in interface LongCollection

Specified by:

iterator in interface LongIterable

Specified by:

iterator in interface LongSet

Specified by:

iterator in class AbstractLongCollection

Returns:

a set iterator

remove

public boolean remove(long v)

Removes the supplied Object from this Set if it is in the Set.

Specified by:

remove in interface LongCollection

Specified by:

remove in interface LongSet

Overrides:

remove in class AbstractLongCollection

Parameters:

v - the long to remove

Returns:

true if an element was removed

See Also:

LongIterator.remove()

size

public int size()

Returns the number of elements in this Set (its cardinality).

Specified by:

size in interface LongCollection

Specified by:

size in interface LongSet

Specified by:

size in class AbstractLongCollection

Returns:

the size of the set