edu.ucla.sspace.util

Interface SparseArray<T>

All Known Subinterfaces:

SparseNumericArray<T>

All Known Implementing Classes:

IntegerMap, SparseDoubleArray, SparseHashArray, SparseIntArray, SparseIntHashArray, SparseLongArray

public interface SparseArray<T>

A interface for array-like classes that use a sparse internal representation to save space. The exact details of performance are specified by the implementation themselves.

Although interfaces cannot enforce constructors, it is suggested that instances implement an additional constructor with an array parameter of the required type. This constructor should make a copy of the array so that changes to one are not propagated.

In addition, it is suggested that instances that wrap Java primitive-type arrays provide two additional methods, getPrimitive and setPrimitive, which operate directly on the primitive types rather than their object equivalents. This allows users to save any performance costs from auto-boxing the primitives.

Method Summary

Methods

Modifier and Type	Method and Description
int	cardinality() Returns the number of non-zero values in this sparse array
T	get(int index) Returns the value of this array at the index.
int[]	getElementIndices() Returns the indices of the array that contain non-null values.
int	length() Returns length of this array.
void	set(int index, T obj) Sets the object as the value at the index.
<E> E[]	toArray(E[] array) Fills the provided array with the values contained in this array that fit within the length of the provided array.

Method Detail

cardinality

int cardinality()

Returns the number of non-zero values in this sparse array

get

T get(int index)

Returns the value of this array at the index.

Parameters:

index - the position in the array

Returns:

the object at the position

getElementIndices

int[] getElementIndices()

Returns the indices of the array that contain non-null values.

Returns:

the indices that contain values

length

int length()

Returns length of this array. Note that implementations may define this according to a preset, fixed length, or using the highest index set in this array.

set

void set(int index,
       T obj)

Sets the object as the value at the index.

Parameters:

index - an index in the array

obj - the value

toArray

<E> E[] toArray(E[] array)

Fills the provided array with the values contained in this array that fit within the length of the provided array.

Throws:

ClassCastException - if the contents of this sparse array are not compatible with the type of the provided array