Class ObjectArrayList<K>
- All Implemented Interfaces:
ObjectCollection<K>
,ObjectIterable<K>
,ObjectList<K>
,Stack<K>
,java.io.Serializable
,java.lang.Cloneable
,java.lang.Comparable<java.util.List<? extends K>>
,java.lang.Iterable<K>
,java.util.Collection<K>
,java.util.List<K>
,java.util.RandomAccess
public class ObjectArrayList<K> extends AbstractObjectList<K> 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. If an
instance of this class was created by
wrapping, backing-array reallocations will be performed using reflection, so
that elements()
can return an array of the same type of the original
array: the comments about efficiency made in
ObjectArrays
apply here. Moreover, you
must take into consideration that assignment to an array not of type
Object[]
is slower due to type checking.
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.objects.AbstractObjectList
AbstractObjectList.ObjectRandomAccessSubList<K>, AbstractObjectList.ObjectSubList<K>
-
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 ObjectArrayList()
Creates a new array list withDEFAULT_INITIAL_CAPACITY
capacity.ObjectArrayList(int capacity)
Creates a new array list with given capacity.ObjectArrayList(ObjectCollection<? extends K> c)
Creates a new array list and fills it with a given type-specific collection.ObjectArrayList(ObjectIterator<? extends K> i)
Creates a new array list and fills it with the elements returned by a type-specific iterator..ObjectArrayList(ObjectList<? extends K> l)
Creates a new array list and fills it with a given type-specific list.ObjectArrayList(java.util.Collection<? extends K> c)
Creates a new array list and fills it with a given collection.ObjectArrayList(java.util.Iterator<? extends K> i)
Creates a new array list and fills it with the elements returned by an iterator..ObjectArrayList(K[] a)
Creates a new array list and fills it with the elements of a given array.ObjectArrayList(K[] a, int offset, int length)
Creates a new array list and fills it with the elements of a given array. -
Method Summary
Modifier and Type Method Description void
add(int index, K k)
boolean
add(K k)
boolean
addAll(int index, ObjectList<? extends K> l)
Inserts all of the elements in the specified type-specific list into this type-specific list at the specified position (optional operation).boolean
addAll(int index, java.util.Collection<? extends K> c)
Adds all of the elements in the specified collection to this list (optional operation).void
addElements(int index, K[] a, int offset, int length)
Adds elements to this type-specific list using optimized system calls.void
clear()
ObjectArrayList<K>
clone()
int
compareTo(ObjectArrayList<? extends K> l)
Compares this array list to another array list.int
compareTo(java.util.List<? extends K> l)
Compares this list to another object.K[]
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(ObjectArrayList<K> l)
Compares this type-specific array list to another one.boolean
equals(java.lang.Object o)
void
forEach(java.util.function.Consumer<? super K> action)
K
get(int index)
void
getElements(int from, java.lang.Object[] a, int offset, int length)
Copies element of this type-specific list into the given array using optimized system calls.int
indexOf(java.lang.Object k)
boolean
isEmpty()
Checks whether the stack is empty.int
lastIndexOf(java.lang.Object k)
ObjectListIterator<K>
listIterator(int index)
Returns a type-specific list iterator on the list starting at a given index.static <K> ObjectArrayList<K>
of()
Creates a new empty array list.static <K> ObjectArrayList<K>
of(K... init)
Creates an array list using an array of elements.K
remove(int index)
boolean
remove(java.lang.Object k)
boolean
removeAll(java.util.Collection<?> c)
void
removeElements(int from, int to)
Removes elements of this type-specific list using optimized system calls.K
set(int index, K k)
void
setElements(int index, K[] 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(java.util.Comparator<? super K> comp)
Sorts this list using a sort assured to be stable.ObjectSpliterator<K>
spliterator()
Returns a type-specific spliterator on the elements of this list.ObjectList<K>
subList(int from, int to)
Returns a type-specific view of the portion of this list from the indexfrom
, inclusive, to the indexto
, exclusive.java.lang.Object[]
toArray()
<K> K[]
toArray(K[] a)
static <K> java.util.stream.Collector<K,?,ObjectArrayList<K>>
toList()
Returns aCollector
that collects aStream
's elements into a new ArrayList.static <K> java.util.stream.Collector<K,?,ObjectArrayList<K>>
toListWithExpectedSize(int expectedSize)
Returns aCollector
that collects aStream
's elements 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(java.util.Comparator<? super K> comp)
Sorts this list using a sort not assured to be stable.static <K> ObjectArrayList<K>
wrap(K[] a)
Wraps a given array into an array list.static <K> ObjectArrayList<K>
wrap(K[] a, int length)
Wraps a given array into an array list of given size.Methods inherited from class it.unimi.dsi.fastutil.objects.AbstractObjectList
addAll, addElements, contains, hashCode, iterator, listIterator, peek, pop, push, top, toString
Methods inherited from class java.util.AbstractCollection
containsAll, retainAll
Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait
Methods inherited from interface java.util.Collection
parallelStream, removeIf, stream, toArray
Methods inherited from interface java.util.List
containsAll, replaceAll, retainAll
Methods inherited from interface it.unimi.dsi.fastutil.objects.ObjectList
addAll, setElements, setElements
-
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
-
ObjectArrayList
public ObjectArrayList(int capacity)Creates a new array list with given capacity.- Parameters:
capacity
- the initial capacity of the array list (may be 0).
-
ObjectArrayList
public ObjectArrayList()Creates a new array list withDEFAULT_INITIAL_CAPACITY
capacity. -
ObjectArrayList
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.
-
ObjectArrayList
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.
-
ObjectArrayList
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.
-
ObjectArrayList
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.
-
ObjectArrayList
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.
-
ObjectArrayList
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.
-
ObjectArrayList
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
Returns the backing array of this list.If this array list was created by wrapping a given array, it is guaranteed that the type of the returned array will be the same. Otherwise, the returned array will be of type
Object[]
(in spite of the declared return type).Warning: This behaviour may cause (unfathomable) run-time errors if a method expects an array actually of type
K[]
, but this methods returns an array of typeObject[]
.- 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(K[], int)
-
toList
Returns aCollector
that collects aStream
's elements into a new ArrayList. -
toListWithExpectedSize
public static <K> java.util.stream.Collector<K,?,ObjectArrayList<K>> toListWithExpectedSize(int expectedSize)Returns aCollector
that collects aStream
's elements into a new ArrayList, potentially pre-allocated to handle the given size. -
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
Description copied from class:AbstractObjectList
- Specified by:
add
in interfacejava.util.List<K>
- Overrides:
add
in classAbstractObjectList<K>
-
add
Description copied from class:AbstractObjectList
- Specified by:
add
in interfacejava.util.Collection<K>
- Specified by:
add
in interfacejava.util.List<K>
- Overrides:
add
in classAbstractObjectList<K>
-
get
- Specified by:
get
in interfacejava.util.List<K>
-
indexOf
public int indexOf(java.lang.Object k)- Specified by:
indexOf
in interfacejava.util.List<K>
- Overrides:
indexOf
in classAbstractObjectList<K>
-
lastIndexOf
public int lastIndexOf(java.lang.Object k)- Specified by:
lastIndexOf
in interfacejava.util.List<K>
- Overrides:
lastIndexOf
in classAbstractObjectList<K>
-
remove
Description copied from class:AbstractObjectList
- Specified by:
remove
in interfacejava.util.List<K>
- Overrides:
remove
in classAbstractObjectList<K>
-
remove
public boolean remove(java.lang.Object k) -
set
Description copied from class:AbstractObjectList
- Specified by:
set
in interfacejava.util.List<K>
- Overrides:
set
in classAbstractObjectList<K>
-
clear
public void clear()Description copied from class:AbstractObjectList
- Specified by:
clear
in interfacejava.util.Collection<K>
- Specified by:
clear
in interfacejava.util.List<K>
- Overrides:
clear
in classAbstractObjectList<K>
-
size
public int size() -
size
public void size(int size)Description copied from interface:ObjectList
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 interfaceObjectList<K>
- Overrides:
size
in classAbstractObjectList<K>
- Parameters:
size
- the new size.
-
isEmpty
public boolean isEmpty()Description copied from interface:Stack
Checks whether 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:ObjectList
Returns a type-specific view of the portion of this list from the indexfrom
, inclusive, to the indexto
, exclusive.- Specified by:
subList
in interfacejava.util.List<K>
- Specified by:
subList
in interfaceObjectList<K>
- Overrides:
subList
in classAbstractObjectList<K>
- See Also:
List.subList(int,int)
-
getElements
public void getElements(int from, java.lang.Object[] a, int offset, int length)Copies element of this type-specific list into the given array using optimized system calls.- Specified by:
getElements
in interfaceObjectList<K>
- Overrides:
getElements
in classAbstractObjectList<K>
- 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 interfaceObjectList<K>
- Overrides:
removeElements
in classAbstractObjectList<K>
- Parameters:
from
- the start index (inclusive).to
- the end index (exclusive).
-
addElements
Adds elements to this type-specific list using optimized system calls.- Specified by:
addElements
in interfaceObjectList<K>
- Overrides:
addElements
in classAbstractObjectList<K>
- 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
Sets elements to this type-specific list using optimized system calls.- Specified by:
setElements
in interfaceObjectList<K>
- Overrides:
setElements
in classAbstractObjectList<K>
- 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
Description copied from class:AbstractObjectList
- Specified by:
forEach
in interfacejava.lang.Iterable<K>
- Overrides:
forEach
in classAbstractObjectList<K>
-
addAll
Description copied from class:AbstractObjectList
Adds all of the elements in the specified collection to this list (optional operation).- Specified by:
addAll
in interfacejava.util.List<K>
- Overrides:
addAll
in classAbstractObjectList<K>
-
addAll
Description copied from interface:ObjectList
Inserts all of the elements in the specified type-specific list into this type-specific list at the specified position (optional operation).- Specified by:
addAll
in interfaceObjectList<K>
- See Also:
List.addAll(int,Collection)
-
removeAll
public boolean removeAll(java.util.Collection<?> c) -
toArray
public java.lang.Object[] toArray()- Specified by:
toArray
in interfacejava.util.Collection<K>
- Specified by:
toArray
in interfacejava.util.List<K>
- Overrides:
toArray
in classAbstractObjectList<K>
-
toArray
public <K> K[] toArray(K[] a)- Specified by:
toArray
in interfacejava.util.Collection<K>
- Specified by:
toArray
in interfacejava.util.List<K>
- Overrides:
toArray
in classAbstractObjectList<K>
-
listIterator
Description copied from class:AbstractObjectList
Returns a type-specific list iterator on the list starting at a given index.- Specified by:
listIterator
in interfacejava.util.List<K>
- Specified by:
listIterator
in interfaceObjectList<K>
- Overrides:
listIterator
in classAbstractObjectList<K>
- 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<K>
- Specified by:
spliterator
in interfacejava.lang.Iterable<K>
- Specified by:
spliterator
in interfacejava.util.List<K>
- Specified by:
spliterator
in interfaceObjectCollection<K>
- Specified by:
spliterator
in interfaceObjectIterable<K>
- Specified by:
spliterator
in interfaceObjectList<K>
- Returns:
- a type-specific spliterator on the elements of this collection.
-
sort
Description copied from interface:ObjectList
Sorts this list using a sort assured to be stable.Pass
null
to sort using natural ordering.Unless a subclass specifies otherwise, the results of the method if the list is concurrently modified during the sort are unspecified.
- Specified by:
sort
in interfacejava.util.List<K>
- Specified by:
sort
in interfaceObjectList<K>
-
unstableSort
Description copied from interface:ObjectList
Sorts this list using a sort not assured to be stable. This differs fromList.sort(java.util.Comparator)
in that the results are not assured to be stable, but may be a bit faster.Pass
null
to sort using natural ordering.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 interfaceObjectList<K>
-
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<K>
- Specified by:
equals
in interfacejava.util.List<K>
- Overrides:
equals
in classAbstractObjectList<K>
-
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
Description copied from class:AbstractObjectList
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<K>
- Overrides:
compareTo
in classAbstractObjectList<K>
- 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.
-