org.graphstream.algorithm
Class FixedArrayList<E>

java.lang.Object
  org.graphstream.algorithm.FixedArrayList<E>

All Implemented Interfaces:

Iterable<E>, Collection<E>, RandomAccess

public class FixedArrayList<E>
extends Object
implements Collection<E>, RandomAccess

Array list with immutable element indices.

A fixed array list is like an array list, but it ensures the property that each element will always stay at the same index, even if elements are removed in between. The counterpart of this property is that the array handles by itself the insertion of new elements (since when an element is removed in the middle, this position can be reused), and therefore indices cannot be chosen (i.e. only the add(Object) and addAll(Collection) methods are usable to insert new elements in the array).

This is the reason why this does not implement the List interface, because the add(int,E) method cannot be implemented.

Furthermore, this array cannot contain null values, because it marks unused positions within the array using the null value.

Since:

20040912

Author:

Antoine Dutot

Constructor Summary

FixedArrayList()

FixedArrayList(int capacity)

Method Summary

boolean	add(E element) Add one element in the array.
boolean	addAll(Collection<? extends E> c)
boolean	addAt(int i, E element) This operation set the i-th cell with the given value.
void	clear()
boolean	contains(Object o)
boolean	containsAll(Collection<?> c)
boolean	equals(Object o)
E	get(int i) I-th element.
int	getLastIndex() Last index used by the add(Object) method.
int	getNextAddIndex() The index that will be used in case of a next insertion in this array.
boolean	hasIndex(int i) True if the given index i references a value.
boolean	isEmpty()
Iterator<E>	iterator()
int	realSize() Real size of the array, counting elements that have been erased.
E	remove(int i) Remove the element at index i.
boolean	remove(Object e) Remove the element e.
boolean	removeAll(Collection<?> c)
boolean	retainAll(Collection<?> c)
int	size() Number of elements in the array.
Object[]	toArray()
<T> T[]	toArray(T[] a)
E	unsafeGet(int i) I-th element.

Methods inherited from class java.lang.Object

getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Collection

hashCode

Constructor Detail

FixedArrayList

public FixedArrayList()

FixedArrayList

public FixedArrayList(int capacity)

Method Detail

size

public int size()

Number of elements in the array.

Specified by:

size in interface Collection<E>

Returns:

The number of elements in the array.

realSize

public int realSize()

Real size of the array, counting elements that have been erased.

See Also:

unsafeGet(int)

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface Collection<E>

hasIndex

public boolean hasIndex(int i)

True if the given index i references a value.

Parameters:

i - The index to test.

Returns:

True if a value exists at the given index.

get

public E get(int i)

I-th element.

Parameters:

i - The element index.

Returns:

The element at index i.

unsafeGet

public E unsafeGet(int i)

I-th element. Like the get(int) method but it does not check the element does not exists at the given index.

Parameters:

i - The element index.

Returns:

The element at index i.

contains

public boolean contains(Object o)

Specified by:

contains in interface Collection<E>

containsAll

public boolean containsAll(Collection<?> c)

Specified by:

containsAll in interface Collection<E>

equals

public boolean equals(Object o)

Specified by:

equals in interface Collection<E>

Overrides:

equals in class Object

iterator

public Iterator<E> iterator()

Specified by:

iterator in interface Iterable<E>

Specified by:

iterator in interface Collection<E>

getLastIndex

public int getLastIndex()

Last index used by the add(Object) method.

Returns:

The last insertion index.

getNextAddIndex

public int getNextAddIndex()

The index that will be used in case of a next insertion in this array.

Returns:

toArray

public Object[] toArray()

Specified by:

toArray in interface Collection<E>

toArray

public <T> T[] toArray(T[] a)

Specified by:

toArray in interface Collection<E>

add

public boolean add(E element)
            throws NullPointerException

Add one element in the array. The index used for inserting the element is then available using getLastIndex(). This method complexity is O(1).

Specified by:

add in interface Collection<E>

Parameters:

element - The element to add.

Returns:

Always true.

Throws:

NullPointerException - If a null value is inserted.

See Also:

getLastIndex()

addAll

public boolean addAll(Collection<? extends E> c)
               throws UnsupportedOperationException

Specified by:

addAll in interface Collection<E>

Throws:

UnsupportedOperationException

addAt

public boolean addAt(int i,
                     E element)

This operation set the i-th cell with the given value. This works only if the cell is empty, or if i is larger or equal to the size of the array (if larger, empty cells are added to fill the gap, and free indices will be used by the add() method). If the cell is not empty, the return value is false. This method is a convenience method, and its complexity is not O(1) like the add() and remove() methods. At worse the complexity is O(n). It is optimized so that when adding the element whose id is the one given by getNextAddIndex() its complexity is O(1).

Parameters:

i - The index of the cell to change.

element - The value to set.

Returns:

false If the insertion was not successful (there was already something in the set).

remove

public E remove(int i)

Remove the element at index i. This method complexity is O(1).

Parameters:

i - Index of the element to remove.

Returns:

The removed element.

remove

public boolean remove(Object e)

Remove the element e. At worse the complexity is O(n).

Specified by:

remove in interface Collection<E>

Parameters:

e - The element to remove.

Returns:

True if removed.

removeAll

public boolean removeAll(Collection<?> c)

Specified by:

removeAll in interface Collection<E>

retainAll

public boolean retainAll(Collection<?> c)

Specified by:

retainAll in interface Collection<E>

clear

public void clear()

Specified by:

clear in interface Collection<E>