it.unimi.dsi.fastutil.longs

Class LongArrayList

java.lang.Object

java.util.AbstractCollection<Long>

it.unimi.dsi.fastutil.longs.AbstractLongCollection

it.unimi.dsi.fastutil.longs.AbstractLongList

it.unimi.dsi.fastutil.longs.LongArrayList

All Implemented Interfaces:

LongCollection, LongIterable, LongList, LongStack, Stack<Long>, Serializable, Cloneable, Comparable<List<? extends Long>>, Iterable<Long>, Collection<Long>, List<Long>, RandomAccess

public class LongArrayList
extends AbstractLongList
implements RandomAccess, Cloneable, Serializable

A type-specific array-based list; provides some additional methods that use polymorphism to avoid (un)boxing.

This class implements a lightweight, fast, open, optimized, reuse-oriented version of array-based lists. Instances of this class represent a list with an array that is enlarged as needed when new entries are created (by dividing the current length by the golden ratio), but is never made smaller (even on a clear()). A family of trimming methods lets you control the size of the backing array; this is particularly useful if you reuse instances of this class. Range checks are equivalent to those of java.util's classes, but they are delayed as much as possible. The backing array is exposed by the elements() method.

This class implements the bulk methods removeElements(), addElements() and getElements() using high-performance system calls (e.g., System.arraycopy() instead of expensive loops.

See Also:

ArrayList, Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class it.unimi.dsi.fastutil.longs.AbstractLongList

AbstractLongList.LongSubList

Field Summary

Fields

Modifier and Type	Field and Description
protected long[]	a The backing array.
static int	DEFAULT_INITIAL_CAPACITY The initial default capacity of an array list.
protected static long	ONEOVERPHI The inverse of the golden ratio times 216.
static long	serialVersionUID
protected int	size The current actual size of the list (never greater than the backing-array length).

Constructor Summary

Constructors

Modifier	Constructor and Description
	LongArrayList() Creates a new array list with DEFAULT_INITIAL_CAPACITY capacity.
	LongArrayList(Collection<? extends Long> c) Creates a new array list and fills it with a given collection.
	LongArrayList(int capacity) Creates a new array list with given capacity.
	LongArrayList(Iterator<? extends Long> i) Creates a new array list and fills it with the elements returned by an iterator..
	LongArrayList(long[] a) Creates a new array list and fills it with the elements of a given array.
protected	LongArrayList(long[] a, boolean dummy) Creates a new array list using a given array.
	LongArrayList(long[] a, int offset, int length) Creates a new array list and fills it with the elements of a given array.
	LongArrayList(LongCollection c) Creates a new array list and fills it with a given type-specific collection.
	LongArrayList(LongIterator i) Creates a new array list and fills it with the elements returned by a type-specific iterator..
	LongArrayList(LongList l) Creates a new array list and fills it with a given type-specific list.

Method Summary

Methods

Modifier and Type	Method and Description
void	add(int index, long k)
boolean	add(long k)
boolean	addAll(int index, LongCollection c) Delegates to a more generic method.
boolean	addAll(int index, LongList l) Delegates to a more generic method.
void	addElements(int index, long[] a, int offset, int length) Adds elements to this type-specific list using optimized system calls.
void	clear()
LongArrayList	clone()
int	compareTo(LongArrayList l) Compares this array list to another array list.
long[]	elements() Returns the backing array of this list.
void	ensureCapacity(int capacity) Ensures that this array list can contain the given number of entries without resizing.
boolean	equals(LongArrayList l) Compares this type-specific array list to another one.
void	getElements(int from, long[] a, int offset, int length) Copies element of this type-specific list into the given array using optimized system calls.
long	getLong(int index)
int	indexOf(long k)
boolean	isEmpty() Checks whether the stack is empty.
int	lastIndexOf(long k)
LongListIterator	listIterator(int index) Returns a type-specific list iterator on the list starting at a given index.
boolean	rem(long k) Note that this method should be called remove(), but the clash with the similarly named index-based method in the List interface forces us to use a distinguished name.
void	removeElements(int from, int to) Removes elements of this type-specific list using optimized system calls.
long	removeLong(int index)
long	set(int index, long k)
int	size()
void	size(int size) Sets the size of this list.
long[]	toLongArray(long[] a) Returns a primitive type array containing the items of this collection.
void	trim() Trims this array list so that the capacity is equal to the size.
void	trim(int n) Trims the backing array if it is too large.
static LongArrayList	wrap(long[] a) Wraps a given array into an array list.
static LongArrayList	wrap(long[] a, int length) Wraps a given array into an array list of given size.

Methods inherited from class it.unimi.dsi.fastutil.longs.AbstractLongList

add, addAll, addAll, addAll, addAll, addElements, compareTo, contains, ensureIndex, ensureRestrictedIndex, equals, get, hashCode, indexOf, iterator, lastIndexOf, listIterator, longListIterator, longListIterator, longSubList, peek, peekLong, pop, popLong, push, push, remove, remove, set, subList, top, topLong, toString

Methods inherited from class it.unimi.dsi.fastutil.longs.AbstractLongCollection

add, contains, containsAll, containsAll, longIterator, rem, removeAll, removeAll, retainAll, retainAll, toArray, toArray, toArray, toLongArray

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.List

add, contains, containsAll, removeAll, retainAll, toArray, toArray

Methods inherited from interface it.unimi.dsi.fastutil.longs.LongCollection

containsAll, longIterator, removeAll, retainAll, toArray, toArray, toLongArray

Field Detail

serialVersionUID

public static final long serialVersionUID

See Also:

Constant Field Values

DEFAULT_INITIAL_CAPACITY

public static final int DEFAULT_INITIAL_CAPACITY

The initial default capacity of an array list.

See Also:

Constant Field Values

ONEOVERPHI

protected static final long ONEOVERPHI

The inverse of the golden ratio times 2¹⁶.

See Also:

Constant Field Values

a

protected transient long[] a

The backing array.

size

protected int size

The current actual size of the list (never greater than the backing-array length).

Constructor Detail

LongArrayList

protected LongArrayList(long[] a,
             boolean dummy)

Creates a new array list using a given array.

This constructor is only meant to be used by the wrapping methods.

Parameters:

a - the array that will be used to back this array list.

LongArrayList

public LongArrayList(int capacity)

Creates a new array list with given capacity.

Parameters:

capacity - the initial capacity of the array list (may be 0).

LongArrayList

public LongArrayList()

Creates a new array list with DEFAULT_INITIAL_CAPACITY capacity.

LongArrayList

public LongArrayList(Collection<? extends Long> c)

Creates a new array list and fills it with a given collection.

Parameters:

c - a collection that will be used to fill the array list.

LongArrayList

public LongArrayList(LongCollection c)

Creates a new array list and fills it with a given type-specific collection.

Parameters:

c - a type-specific collection that will be used to fill the array list.

LongArrayList

public LongArrayList(LongList l)

Creates a new array list and fills it with a given type-specific list.

Parameters:

l - a type-specific list that will be used to fill the array list.

LongArrayList

public LongArrayList(long[] a)

Creates a new array list and fills it with the elements of a given array.

Parameters:

a - an array whose elements will be used to fill the array list.

LongArrayList

public LongArrayList(long[] a,
             int offset,
             int length)

Creates a new array list and fills it with the elements of a given array.

Parameters:

a - an array whose elements will be used to fill the array list.

offset - the first element to use.

length - the number of elements to use.

LongArrayList

public LongArrayList(Iterator<? extends Long> i)

Creates a new array list and fills it with the elements returned by an iterator..

Parameters:

i - an iterator whose returned elements will fill the array list.

LongArrayList

public LongArrayList(LongIterator i)

Creates a new array list and fills it with the elements returned by a type-specific iterator..

Parameters:

i - a type-specific iterator whose returned elements will fill the array list.

Method Detail

elements

public long[] elements()

Returns the backing array of this list.

Returns:

the backing array.

wrap

public static LongArrayList wrap(long[] a,
                 int length)

Wraps a given array into an array list of given size.

Parameters:

a - an array to wrap.

length - the length of the resulting array list.

Returns:

a new array list of the given size, wrapping the given array.

wrap

public static LongArrayList wrap(long[] a)

Wraps a given array into an array list.

Parameters:

a - an array to wrap.

Returns:

a new array list wrapping the given array.

ensureCapacity

public void ensureCapacity(int capacity)

Ensures that this array list can contain the given number of entries without resizing.

Parameters:

capacity - the new minimum capacity for this array list.

add

public void add(int index,
       long k)

Specified by:

add in interface LongList

Overrides:

add in class AbstractLongList

See Also:

List.add(int,Object)

add

public boolean add(long k)

Specified by:

add in interface LongCollection

Specified by:

add in interface LongList

Overrides:

add in class AbstractLongList

See Also:

Collection.add(Object)

getLong

public long getLong(int index)

Specified by:

getLong in interface LongList

See Also:

List.get(int)

indexOf

public int indexOf(long k)

Specified by:

indexOf in interface LongList

Overrides:

indexOf in class AbstractLongList

See Also:

List.indexOf(Object)

lastIndexOf

public int lastIndexOf(long k)

Specified by:

lastIndexOf in interface LongList

Overrides:

lastIndexOf in class AbstractLongList

See Also:

List.lastIndexOf(Object)

removeLong

public long removeLong(int index)

Specified by:

removeLong in interface LongList

Overrides:

removeLong in class AbstractLongList

See Also:

List.remove(int)

rem

public boolean rem(long k)

Description copied from interface: LongCollection

Note that this method should be called remove(), but the clash with the similarly named index-based method in the List interface forces us to use a distinguished name. For simplicity, the set interfaces reinstates remove().

Specified by:

rem in interface LongCollection

Overrides:

rem in class AbstractLongList

See Also:

Collection.remove(Object)

set

public long set(int index,
       long k)

Specified by:

set in interface LongList

Overrides:

set in class AbstractLongList

See Also:

List.set(int,Object)

clear

public void clear()

Specified by:

clear in interface Collection<Long>

Specified by:

clear in interface List<Long>

Overrides:

clear in class AbstractCollection<Long>

size

public int size()

Specified by:

size in interface Collection<Long>

Specified by:

size in interface List<Long>

Specified by:

size in class AbstractCollection<Long>

size

public void size(int size)

Description copied from interface: LongList

Sets the size of this list.

If the specified size is smaller than the current size, the last elements are discarded. Otherwise, they are filled with 0/null/false.

Specified by:

size in interface LongList

Overrides:

size in class AbstractLongList

Parameters:

size - the new size.

isEmpty

public boolean isEmpty()

Description copied from interface: Stack

Checks whether the stack is empty.

Specified by:

isEmpty in interface Stack<Long>

Specified by:

isEmpty in interface Collection<Long>

Specified by:

isEmpty in interface List<Long>

Overrides:

isEmpty in class AbstractLongCollection

Returns:

true if the stack is empty.

trim

public void trim()

Trims this array list so that the capacity is equal to the size.

See Also:

ArrayList.trimToSize()

trim

public void trim(int n)

Trims the backing array if it is too large. If the current array length is smaller than or equal to n, this method does nothing. Otherwise, it trims the array length to the maximum between n and size().

This method is useful when reusing lists. Clearing a list leaves the array length untouched. If you are reusing a list many times, you can call this method with a typical size to avoid keeping around a very large array just because of a few large transient lists.

Parameters:

n - the threshold for the trimming.

getElements

public void getElements(int from,
               long[] a,
               int offset,
               int length)

Copies element of this type-specific list into the given array using optimized system calls.

Specified by:

getElements in interface LongList

Overrides:

getElements in class AbstractLongList

Parameters:

from - the start index (inclusive).

a - the destination array.

offset - the offset into the destination array where to store the first element copied.

length - the number of elements to be copied.

removeElements

public void removeElements(int from,
                  int to)

Removes elements of this type-specific list using optimized system calls.

Specified by:

removeElements in interface LongList

Overrides:

removeElements in class AbstractLongList

Parameters:

from - the start index (inclusive).

to - the end index (exclusive).

addElements

public void addElements(int index,
               long[] a,
               int offset,
               int length)

Adds elements to this type-specific list using optimized system calls.

Specified by:

addElements in interface LongList

Overrides:

addElements in class AbstractLongList

Parameters:

index - the index at which to add elements.

a - the array containing the elements.

offset - the offset of the first element to add.

length - the number of elements to add.

toLongArray

public long[] toLongArray(long[] a)

Description copied from interface: LongCollection

Returns a primitive type array containing the items of this collection.

Note that, contrarily to Collection.toArray(Object[]), this methods just writes all elements of this collection: no special value will be added after the last one.

Specified by:

toLongArray in interface LongCollection

Overrides:

toLongArray in class AbstractLongCollection

Parameters:

a - if this array is big enough, it will be used to store this collection.

Returns:

a primitive type array containing the items of this collection.

See Also:

Collection.toArray(Object[])

addAll

public boolean addAll(int index,
             LongCollection c)

Description copied from class: AbstractLongList

Delegates to a more generic method.

Specified by:

addAll in interface LongList

Overrides:

addAll in class AbstractLongList

See Also:

List.add(int,Object)

addAll

public boolean addAll(int index,
             LongList l)

Description copied from class: AbstractLongList

Delegates to a more generic method.

Specified by:

addAll in interface LongList

Overrides:

addAll in class AbstractLongList

See Also:

List.add(int,Object)

listIterator

public LongListIterator listIterator(int index)

Description copied from interface: LongList

Returns a type-specific list iterator on the list starting at a given index.

Specified by:

listIterator in interface LongList

Specified by:

listIterator in interface List<Long>

Overrides:

listIterator in class AbstractLongList

See Also:

List.listIterator(int)

clone

public LongArrayList clone()

Overrides:

clone in class Object

equals

public boolean equals(LongArrayList l)

Compares this type-specific array list to another one.

This method exists only for sake of efficiency. The implementation inherited from the abstract implementation would already work.

Parameters:

l - a type-specific array list.

Returns:

true if the argument contains the same elements of this type-specific array list.

compareTo

public int compareTo(LongArrayList l)

Compares this array list to another array list.

This method exists only for sake of efficiency. The implementation inherited from the abstract implementation would already work.

Parameters:

l - an array list.

Returns:

a negative integer, zero, or a positive integer as this list is lexicographically less than, equal to, or greater than the argument.