Class IntArrayList
- All Implemented Interfaces:
IntCollection
,IntIterable
,IntList
,IntStack
,Stack<java.lang.Integer>
,java.io.Serializable
,java.lang.Cloneable
,java.lang.Comparable<java.util.List<? extends java.lang.Integer>>
,java.lang.Iterable<java.lang.Integer>
,java.util.Collection<java.lang.Integer>
,java.util.List<java.lang.Integer>
,java.util.RandomAccess
public class IntArrayList extends AbstractIntList implements java.util.RandomAccess, java.lang.Cloneable, java.io.Serializable
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
increasing its current length by 50%), 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.ints.AbstractIntList
AbstractIntList.IntRandomAccessSubList, AbstractIntList.IntSubList
-
Field Summary
Fields Modifier and Type Field Description static int
DEFAULT_INITIAL_CAPACITY
The initial default capacity of an array list. -
Constructor Summary
Constructors Constructor Description IntArrayList()
Creates a new array list withDEFAULT_INITIAL_CAPACITY
capacity.IntArrayList(int capacity)
Creates a new array list with given capacity.IntArrayList(int[] a)
Creates a new array list and fills it with the elements of a given array.IntArrayList(int[] a, int offset, int length)
Creates a new array list and fills it with the elements of a given array.IntArrayList(IntCollection c)
Creates a new array list and fills it with a given type-specific collection.IntArrayList(IntIterator i)
Creates a new array list and fills it with the elements returned by a type-specific iterator..IntArrayList(IntList l)
Creates a new array list and fills it with a given type-specific list.IntArrayList(java.util.Collection<? extends java.lang.Integer> c)
Creates a new array list and fills it with a given collection.IntArrayList(java.util.Iterator<? extends java.lang.Integer> i)
Creates a new array list and fills it with the elements returned by an iterator.. -
Method Summary
Modifier and Type Method Description boolean
add(int k)
Ensures that this collection contains the specified element (optional operation).void
add(int index, int k)
Inserts the specified element at the specified position in this list (optional operation).boolean
addAll(int index, IntCollection c)
Inserts all of the elements in the specified type-specific collection into this type-specific list at the specified position (optional operation).boolean
addAll(int index, IntList l)
Inserts all of the elements in the specified type-specific list into this type-specific list at the specified position (optional operation).void
addElements(int index, int[] a, int offset, int length)
Adds elements to this type-specific list using optimized system calls.void
clear()
IntArrayList
clone()
int
compareTo(IntArrayList l)
Compares this array list to another array list.int
compareTo(java.util.List<? extends java.lang.Integer> l)
Compares this list to another object.int[]
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(IntArrayList l)
Compares this type-specific array list to another one.boolean
equals(java.lang.Object o)
void
forEach(java.util.function.IntConsumer action)
Performs the given action for each element of this type-specificIterable
until all elements have been processed or the action throws an exception.void
getElements(int from, int[] a, int offset, int length)
Copies element of this type-specific list into the given array using optimized system calls.int
getInt(int index)
Returns the element at the specified position in this list.int
indexOf(int k)
Returns the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element.boolean
isEmpty()
Checks whether the stack is empty.int
lastIndexOf(int k)
Returns the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element.IntListIterator
listIterator(int index)
Returns a type-specific list iterator on the list starting at a given index.static IntArrayList
of()
Creates a new empty array list.static IntArrayList
of(int... init)
Creates an array list using an array of elements.boolean
rem(int k)
Removes a single instance of the specified element from this collection, if it is present (optional operation).boolean
removeAll(IntCollection c)
Remove from this collection all elements in the given type-specific collection.void
removeElements(int from, int to)
Removes elements of this type-specific list using optimized system calls.int
removeInt(int index)
Removes the element at the specified position in this list (optional operation).int
set(int index, int k)
Replaces the element at the specified position in this list with the specified element (optional operation).void
setElements(int index, int[] a, int offset, int length)
Sets elements to this type-specific list using optimized system calls.int
size()
void
size(int size)
Sets the size of this list.void
sort(IntComparator comp)
Sort a list using a type-specific comparator.IntSpliterator
spliterator()
Returns a type-specific spliterator on the elements of this list.IntList
subList(int from, int to)
Returns a type-specific view of the portion of this list from the indexfrom
, inclusive, to the indexto
, exclusive.int[]
toArray(int[] a)
Returns an array containing all of the elements in this collection; the runtime type of the returned array is that of the specified array.static IntArrayList
toList(java.util.stream.IntStream stream)
Collects the result of a primitiveStream
into a new ArrayList.static IntArrayList
toListWithExpectedSize(java.util.stream.IntStream stream, int expectedSize)
Collects the result of a primitiveStream
into a new ArrayList, potentially pre-allocated to handle the given size.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.void
unstableSort(IntComparator comp)
Sorts this list using a sort not assured to be stable.static IntArrayList
wrap(int[] a)
Wraps a given array into an array list.static IntArrayList
wrap(int[] a, int length)
Wraps a given array into an array list of given size.Methods inherited from class it.unimi.dsi.fastutil.ints.AbstractIntList
addAll, addAll, addAll, addElements, contains, hashCode, iterator, listIterator, peekInt, popInt, push, replaceAll, toIntArray, topInt, toString
Methods inherited from class it.unimi.dsi.fastutil.ints.AbstractIntCollection
add, contains, containsAll, containsAll, forEach, remove, removeAll, removeIf, retainAll, retainAll, toIntArray
Methods inherited from class java.util.AbstractCollection
toArray, toArray
Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait
Methods inherited from interface java.util.Collection
toArray
Methods inherited from interface it.unimi.dsi.fastutil.ints.IntCollection
containsAll, intIterator, intParallelStream, intSpliterator, intStream, parallelStream, removeIf, removeIf, removeIf, retainAll, stream, toIntArray
Methods inherited from interface it.unimi.dsi.fastutil.ints.IntIterable
forEach, forEach
Methods inherited from interface it.unimi.dsi.fastutil.ints.IntList
add, add, addAll, contains, get, indexOf, lastIndexOf, remove, remove, replaceAll, replaceAll, set, setElements, setElements, sort, unstableSort
Methods inherited from interface java.util.List
containsAll, removeAll, retainAll, toArray, toArray
-
Field Details
-
DEFAULT_INITIAL_CAPACITY
public static final int DEFAULT_INITIAL_CAPACITYThe initial default capacity of an array list.- See Also:
- Constant Field Values
-
-
Constructor Details
-
IntArrayList
public IntArrayList(int capacity)Creates a new array list with given capacity.- Parameters:
capacity
- the initial capacity of the array list (may be 0).
-
IntArrayList
public IntArrayList()Creates a new array list withDEFAULT_INITIAL_CAPACITY
capacity. -
IntArrayList
public IntArrayList(java.util.Collection<? extends java.lang.Integer> 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.
-
IntArrayList
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.
-
IntArrayList
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.
-
IntArrayList
public IntArrayList(int[] 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.
-
IntArrayList
public IntArrayList(int[] 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.
-
IntArrayList
public IntArrayList(java.util.Iterator<? extends java.lang.Integer> 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.
-
IntArrayList
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 Details
-
elements
public int[] elements()Returns the backing array of this list.- Returns:
- the backing array.
-
wrap
Wraps a given array into an array list of given size.Note it is guaranteed that the type of the array returned by
elements()
will be the same (see the comments in the class documentation).- 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
Wraps a given array into an array list.Note it is guaranteed that the type of the array returned by
elements()
will be the same (see the comments in the class documentation).- Parameters:
a
- an array to wrap.- Returns:
- a new array list wrapping the given array.
-
of
Creates a new empty array list.- Returns:
- a new empty array list.
-
of
Creates an array list using an array of elements.- Parameters:
init
- a the array the will become the new backing array of the array list.- Returns:
- a new array list backed by the given array.
- See Also:
wrap(int[], int)
-
toList
Collects the result of a primitiveStream
into a new ArrayList.This method performs a terminal operation on the given
Stream
- API Notes:
- Taking a primitive stream instead of returning something like a
Collector
is necessary because there is no primitiveCollector
equivalent in the Java API.
-
toListWithExpectedSize
public static IntArrayList toListWithExpectedSize(java.util.stream.IntStream stream, int expectedSize)Collects the result of a primitiveStream
into a new ArrayList, potentially pre-allocated to handle the given size.This method performs a terminal operation on the given
Stream
- API Notes:
- Taking a primitive stream instead returning something like a
Collector
is necessary because there is no primitiveCollector
equivalent in the Java API.
-
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, int k)Description copied from class:AbstractIntList
Inserts the specified element at the specified position in this list (optional operation).- Specified by:
add
in interfaceIntList
- Overrides:
add
in classAbstractIntList
- See Also:
List.add(int,Object)
-
add
public boolean add(int k)Description copied from class:AbstractIntList
Ensures that this collection contains the specified element (optional operation).- Specified by:
add
in interfaceIntCollection
- Specified by:
add
in interfaceIntList
- Overrides:
add
in classAbstractIntList
- See Also:
Collection.add(Object)
-
getInt
public int getInt(int index)Description copied from interface:IntList
Returns the element at the specified position in this list. -
indexOf
public int indexOf(int k)Description copied from interface:IntList
Returns the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element.- Specified by:
indexOf
in interfaceIntList
- Overrides:
indexOf
in classAbstractIntList
- See Also:
List.indexOf(Object)
-
lastIndexOf
public int lastIndexOf(int k)Description copied from interface:IntList
Returns the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element.- Specified by:
lastIndexOf
in interfaceIntList
- Overrides:
lastIndexOf
in classAbstractIntList
- See Also:
List.lastIndexOf(Object)
-
removeInt
public int removeInt(int index)Description copied from class:AbstractIntList
Removes the element at the specified position in this list (optional operation).- Specified by:
removeInt
in interfaceIntList
- Overrides:
removeInt
in classAbstractIntList
- See Also:
List.remove(int)
-
rem
public boolean rem(int k)Description copied from class:AbstractIntList
Removes a single instance of the specified element from this collection, if it is present (optional operation).- Specified by:
rem
in interfaceIntCollection
- Overrides:
rem
in classAbstractIntList
- See Also:
List.remove(Object)
-
set
public int set(int index, int k)Description copied from class:AbstractIntList
Replaces the element at the specified position in this list with the specified element (optional operation).- Specified by:
set
in interfaceIntList
- Overrides:
set
in classAbstractIntList
- See Also:
List.set(int,Object)
-
clear
public void clear()Description copied from class:AbstractIntList
- Specified by:
clear
in interfacejava.util.Collection<java.lang.Integer>
- Specified by:
clear
in interfacejava.util.List<java.lang.Integer>
- Overrides:
clear
in classAbstractIntList
-
size
public int size()- Specified by:
size
in interfacejava.util.Collection<java.lang.Integer>
- Specified by:
size
in interfacejava.util.List<java.lang.Integer>
- Specified by:
size
in classjava.util.AbstractCollection<java.lang.Integer>
-
size
public void size(int size)Description copied from interface:IntList
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 interfaceIntList
- Overrides:
size
in classAbstractIntList
- Parameters:
size
- the new size.
-
isEmpty
public boolean isEmpty()Description copied from interface:Stack
Checks whether the stack is empty.- Specified by:
isEmpty
in interfacejava.util.Collection<java.lang.Integer>
- Specified by:
isEmpty
in interfacejava.util.List<java.lang.Integer>
- Specified by:
isEmpty
in interfaceStack<java.lang.Integer>
- Overrides:
isEmpty
in classjava.util.AbstractCollection<java.lang.Integer>
- 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 ton
, this method does nothing. Otherwise, it trims the array length to the maximum betweenn
andsize()
.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.
-
subList
Description copied from interface:IntList
Returns a type-specific view of the portion of this list from the indexfrom
, inclusive, to the indexto
, exclusive.- Specified by:
subList
in interfaceIntList
- Specified by:
subList
in interfacejava.util.List<java.lang.Integer>
- Overrides:
subList
in classAbstractIntList
- See Also:
List.subList(int,int)
-
getElements
public void getElements(int from, int[] a, int offset, int length)Copies element of this type-specific list into the given array using optimized system calls.- Specified by:
getElements
in interfaceIntList
- Overrides:
getElements
in classAbstractIntList
- 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 interfaceIntList
- Overrides:
removeElements
in classAbstractIntList
- Parameters:
from
- the start index (inclusive).to
- the end index (exclusive).
-
addElements
public void addElements(int index, int[] a, int offset, int length)Adds elements to this type-specific list using optimized system calls.- Specified by:
addElements
in interfaceIntList
- Overrides:
addElements
in classAbstractIntList
- 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.
-
setElements
public void setElements(int index, int[] a, int offset, int length)Sets elements to this type-specific list using optimized system calls.- Specified by:
setElements
in interfaceIntList
- Overrides:
setElements
in classAbstractIntList
- Parameters:
index
- the index at which to start setting elements.a
- the array containing the elements.offset
- the offset of the first element to add.length
- the number of elements to add.
-
forEach
public void forEach(java.util.function.IntConsumer action)Description copied from class:AbstractIntList
Performs the given action for each element of this type-specificIterable
until all elements have been processed or the action throws an exception.- Specified by:
forEach
in interfaceIntIterable
- Overrides:
forEach
in classAbstractIntList
- Parameters:
action
- the action to be performed for each element.- See Also:
Iterable.forEach(java.util.function.Consumer)
-
addAll
Description copied from interface:IntList
Inserts all of the elements in the specified type-specific collection into this type-specific list at the specified position (optional operation).- Specified by:
addAll
in interfaceIntList
- Overrides:
addAll
in classAbstractIntList
- See Also:
List.addAll(int,java.util.Collection)
-
addAll
Description copied from interface:IntList
Inserts all of the elements in the specified type-specific list into this type-specific list at the specified position (optional operation). -
removeAll
Description copied from interface:IntCollection
Remove from this collection all elements in the given type-specific collection.- Specified by:
removeAll
in interfaceIntCollection
- Overrides:
removeAll
in classAbstractIntCollection
- Parameters:
c
- a type-specific collection.- Returns:
true
if this collection changed as a result of the call.- See Also:
Collection.removeAll(Collection)
-
toArray
public int[] toArray(int[] a)Description copied from interface:IntCollection
Returns an array containing all of the elements in this collection; the runtime type of the returned array is that of the specified array.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:
toArray
in interfaceIntCollection
- Overrides:
toArray
in classAbstractIntList
- 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[])
-
listIterator
Description copied from class:AbstractIntList
Returns a type-specific list iterator on the list starting at a given index.- Specified by:
listIterator
in interfaceIntList
- Specified by:
listIterator
in interfacejava.util.List<java.lang.Integer>
- Overrides:
listIterator
in classAbstractIntList
- See Also:
List.listIterator(int)
-
spliterator
Returns a type-specific spliterator on the elements of this list.List spliterators must report at least
Spliterator.SIZED
andSpliterator.ORDERED
.See
List.spliterator()
for more documentation on the requirements of the returned spliterator.The returned spliterator is late-binding; it will track structural changes after the current index, up until the first
trySplit()
, at which point the maximum index will be fixed.
Structural changes before the current index or after the firsttrySplit()
will result in unspecified behavior.- Specified by:
spliterator
in interfacejava.util.Collection<java.lang.Integer>
- Specified by:
spliterator
in interfaceIntCollection
- Specified by:
spliterator
in interfaceIntIterable
- Specified by:
spliterator
in interfaceIntList
- Specified by:
spliterator
in interfacejava.lang.Iterable<java.lang.Integer>
- Specified by:
spliterator
in interfacejava.util.List<java.lang.Integer>
- Returns:
- a type-specific spliterator on the elements of this collection.
-
sort
Description copied from interface:IntList
Sort a list using a type-specific comparator.Pass
null
to sort using natural ordering. -
unstableSort
Description copied from interface:IntList
Sorts this list using a sort not assured to be stable.Pass
null
to sort using natural ordering.This differs from
List.sort(java.util.Comparator)
in that the results are not assured to be stable, but may be a bit faster.Unless a subclass specifies otherwise, the results of the method if the list is concurrently modified during the sort are unspecified.
- Specified by:
unstableSort
in interfaceIntList
-
clone
-
equals
Compares this type-specific array list to another one.- Parameters:
l
- a type-specific array list.- Returns:
- true if the argument contains the same elements of this type-specific array list.
- API Notes:
- This method exists only for sake of efficiency. The implementation inherited from the abstract implementation would already work.
-
equals
public boolean equals(java.lang.Object o)- Specified by:
equals
in interfacejava.util.Collection<java.lang.Integer>
- Specified by:
equals
in interfacejava.util.List<java.lang.Integer>
- Overrides:
equals
in classAbstractIntList
-
compareTo
Compares this array list to another array list.- 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.
- API Notes:
- This method exists only for sake of efficiency. The implementation inherited from the abstract implementation would already work.
-
compareTo
public int compareTo(java.util.List<? extends java.lang.Integer> l)Description copied from class:AbstractIntList
Compares this list to another object. If the argument is aList
, this method performs a lexicographical comparison; otherwise, it throws aClassCastException
.- Specified by:
compareTo
in interfacejava.lang.Comparable<java.util.List<? extends java.lang.Integer>>
- Overrides:
compareTo
in classAbstractIntList
- Parameters:
l
- a list.- Returns:
- if the argument is a
List
, a negative integer, zero, or a positive integer as this list is lexicographically less than, equal to, or greater than the argument.
-