Class ObjectArrayList<K>
- java.lang.Object
-
- java.util.AbstractCollection<K>
-
- it.unimi.dsi.fastutil.objects.AbstractObjectCollection<K>
-
- it.unimi.dsi.fastutil.objects.AbstractObjectList<K>
-
- it.unimi.dsi.fastutil.objects.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
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 doubling the current length), 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 ofjava.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 thatelements()
can return an array of the same type of the original array: the comments about efficiency made inObjectArrays
apply here. Moreover, you must take into consideration that assignment to an array not of typeObject[]
is slower due to type checking.This class implements the bulk methods
removeElements()
,addElements()
andgetElements()
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.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
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description void
add(int index, K k)
boolean
add(K k)
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.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.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(K... init)
Creates an array list using a list 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)
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, addAll, addElements, compareTo, contains, equals, hashCode, iterator, listIterator, peek, pop, push, subList, top, toString
-
Methods inherited from interface java.util.List
containsAll, replaceAll, retainAll, spliterator, toArray, toArray
-
Methods inherited from interface it.unimi.dsi.fastutil.objects.ObjectList
setElements, setElements
-
-
-
-
Field Detail
-
DEFAULT_INITIAL_CAPACITY
public static final int DEFAULT_INITIAL_CAPACITY
The initial default capacity of an array list.- See Also:
- Constant Field Values
-
-
Constructor Detail
-
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
public ObjectArrayList(java.util.Collection<? extends K> 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.
-
ObjectArrayList
public ObjectArrayList(ObjectCollection<? extends K> 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.
-
ObjectArrayList
public ObjectArrayList(ObjectList<? extends K> 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.
-
ObjectArrayList
public ObjectArrayList(K[] 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.
-
ObjectArrayList
public ObjectArrayList(K[] 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.
-
ObjectArrayList
public ObjectArrayList(java.util.Iterator<? extends K> 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.
-
ObjectArrayList
public ObjectArrayList(ObjectIterator<? extends K> 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 K[] 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
public static <K> ObjectArrayList<K> wrap(K[] a, int length)
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
public static <K> ObjectArrayList<K> wrap(K[] a)
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
@SafeVarargs public static <K> ObjectArrayList<K> of(K... init)
Creates an array list using a list of elements.- Parameters:
init
- a list of elements that will be used to initialize the list.- Returns:
- a new array list containing the given elements.
-
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, K k)
Description copied from class:AbstractObjectList
This implementation always throws an
UnsupportedOperationException
.- Specified by:
add
in interfacejava.util.List<K>
- Overrides:
add
in classAbstractObjectList<K>
-
add
public boolean add(K k)
Description copied from class:AbstractObjectList
This implementation delegates to the type-specific version of
List.add(int, Object)
.- Specified by:
add
in interfacejava.util.Collection<K>
- Specified by:
add
in interfacejava.util.List<K>
- Overrides:
add
in classAbstractObjectList<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
public K remove(int index)
Description copied from class:AbstractObjectList
This implementation always throws an
UnsupportedOperationException
.- Specified by:
remove
in interfacejava.util.List<K>
- Overrides:
remove
in classAbstractObjectList<K>
-
remove
public boolean remove(java.lang.Object k)
-
set
public K set(int index, K k)
Description copied from class:AbstractObjectList
This implementation always throws an
UnsupportedOperationException
.- Specified by:
set
in interfacejava.util.List<K>
- Overrides:
set
in classAbstractObjectList<K>
-
clear
public void clear()
Description copied from class:AbstractObjectList
This implementation delegates to
AbstractObjectList.removeElements(int, int)
.- 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.
-
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
public void addElements(int index, K[] a, int offset, int length)
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
public void setElements(int index, K[] a, int offset, int length)
Sets elements to this type-specific list using optimized system calls.- Specified by:
setElements
in interfaceObjectList<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.
-
removeAll
public boolean removeAll(java.util.Collection<?> c)
-
listIterator
public ObjectListIterator<K> listIterator(int index)
Description copied from class:AbstractObjectList
Returns a type-specific list iterator on the list starting at a given index.This implementation is based on the random-access methods.
- Specified by:
listIterator
in interfacejava.util.List<K>
- Specified by:
listIterator
in interfaceObjectList<K>
- Overrides:
listIterator
in classAbstractObjectList<K>
- See Also:
List.listIterator(int)
-
sort
public void sort(java.util.Comparator<? super K> comp)
- Specified by:
sort
in interfacejava.util.List<K>
-
unstableSort
public void unstableSort(java.util.Comparator<? super K> comp)
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.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
public ObjectArrayList<K> clone()
-
equals
public boolean equals(ObjectArrayList<K> 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(ObjectArrayList<? extends K> 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.
-
-