it.unimi.dsi.fastutil.ints
Class IntArrayList

java.lang.Object
  extended by java.util.AbstractCollection<java.lang.Integer>
      extended by it.unimi.dsi.fastutil.ints.AbstractIntCollection
          extended by it.unimi.dsi.fastutil.ints.AbstractIntList
              extended by it.unimi.dsi.fastutil.ints.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

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 its 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 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.IntSubList
 
Field Summary
static int DEFAULT_INITIAL_CAPACITY
          The initial default capacity of an array list.
 
Constructor Summary
IntArrayList()
          Creates a new array list with DEFAULT_INITIAL_CAPACITY capacity.
IntArrayList(java.util.Collection<? extends java.lang.Integer> c)
          Creates a new array list and fills it with a given collection.
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.Iterator<? extends java.lang.Integer> i)
          Creates a new array list and fills it with the elements returned by an iterator..
 
Method Summary
 boolean add(int k)
           
 void add(int index, int k)
           
 boolean addAll(int index, IntCollection c)
          Delegates to a more generic method.
 boolean addAll(int index, IntList l)
          Delegates to a more generic method.
 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[] 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.
 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)
           
 int indexOf(int k)
           
 boolean isEmpty()
          Checks whether the stack is empty.
 int lastIndexOf(int k)
           
 IntListIterator listIterator(int index)
          Returns a type-specific list iterator on the list starting at a given index.
 boolean rem(int 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.
 int removeInt(int index)
           
 int set(int index, int k)
           
 int size()
           
 void size(int size)
          Sets the size of this list.
 int[] toIntArray(int[] 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 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
add, addAll, addAll, addAll, addAll, addElements, compareTo, contains, equals, get, hashCode, indexOf, intListIterator, intListIterator, intSubList, iterator, lastIndexOf, listIterator, peek, peekInt, pop, popInt, push, push, remove, remove, set, subList, top, topInt, toString
 
Methods inherited from class it.unimi.dsi.fastutil.ints.AbstractIntCollection
add, contains, containsAll, containsAll, intIterator, rem, removeAll, removeAll, retainAll, retainAll, toArray, toArray, toArray, toIntArray
 
Methods inherited from class java.lang.Object
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.ints.IntCollection
containsAll, intIterator, removeAll, retainAll, toArray, toArray, toIntArray
 

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

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 with DEFAULT_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

public IntArrayList(IntCollection 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.

IntArrayList

public IntArrayList(IntList 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.

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

public IntArrayList(IntIterator 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 int[] elements()
Returns the backing array of this list.

Returns:
the backing array.

wrap

public static IntArrayList wrap(int[] 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 IntArrayList wrap(int[] 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,
                int k)
Specified by:
add in interface IntList
Overrides:
add in class AbstractIntList
See Also:
List.add(int,Object)

add

public boolean add(int k)
Specified by:
add in interface IntCollection
Specified by:
add in interface IntList
Overrides:
add in class AbstractIntList
See Also:
Collection.add(Object)

getInt

public int getInt(int index)
Specified by:
getInt in interface IntList
See Also:
List.get(int)

indexOf

public int indexOf(int k)
Specified by:
indexOf in interface IntList
Overrides:
indexOf in class AbstractIntList
See Also:
List.indexOf(Object)

lastIndexOf

public int lastIndexOf(int k)
Specified by:
lastIndexOf in interface IntList
Overrides:
lastIndexOf in class AbstractIntList
See Also:
List.lastIndexOf(Object)

removeInt

public int removeInt(int index)
Specified by:
removeInt in interface IntList
Overrides:
removeInt in class AbstractIntList
See Also:
List.remove(int)

rem

public boolean rem(int k)
Description copied from interface: IntCollection
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 IntCollection
Overrides:
rem in class AbstractIntList
See Also:
Collection.remove(Object)

set

public int set(int index,
               int k)
Specified by:
set in interface IntList
Overrides:
set in class AbstractIntList
See Also:
List.set(int,Object)

clear

public void clear()
Specified by:
clear in interface java.util.Collection<java.lang.Integer>
Specified by:
clear in interface java.util.List<java.lang.Integer>
Overrides:
clear in class java.util.AbstractCollection<java.lang.Integer>

size

public int size()
Specified by:
size in interface java.util.Collection<java.lang.Integer>
Specified by:
size in interface java.util.List<java.lang.Integer>
Specified by:
size in class java.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 interface IntList
Overrides:
size in class AbstractIntList
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<java.lang.Integer>
Specified by:
isEmpty in interface java.util.Collection<java.lang.Integer>
Specified by:
isEmpty in interface java.util.List<java.lang.Integer>
Overrides:
isEmpty in class AbstractIntCollection
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,
                        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 interface IntList
Overrides:
getElements in class AbstractIntList
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 IntList
Overrides:
removeElements in class AbstractIntList
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 interface IntList
Overrides:
addElements in class AbstractIntList
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.

toIntArray

public int[] toIntArray(int[] a)
Description copied from interface: IntCollection
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:
toIntArray in interface IntCollection
Overrides:
toIntArray in class AbstractIntCollection
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,
                      IntCollection c)
Description copied from class: AbstractIntList
Delegates to a more generic method.

Specified by:
addAll in interface IntList
Overrides:
addAll in class AbstractIntList
See Also:
List.add(int,Object)

addAll

public boolean addAll(int index,
                      IntList l)
Description copied from class: AbstractIntList
Delegates to a more generic method.

Specified by:
addAll in interface IntList
Overrides:
addAll in class AbstractIntList
See Also:
List.add(int,Object)

listIterator

public IntListIterator listIterator(int index)
Description copied from interface: IntList
Returns a type-specific list iterator on the list starting at a given index.

Specified by:
listIterator in interface IntList
Specified by:
listIterator in interface java.util.List<java.lang.Integer>
Overrides:
listIterator in class AbstractIntList
See Also:
List.listIterator(int)

clone

public IntArrayList clone()
Overrides:
clone in class java.lang.Object

equals

public boolean equals(IntArrayList 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(IntArrayList 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.