de.lmu.ifi.dbs.elki.utilities.datastructures.arraylike

Class ArrayLikeUtil

java.lang.Object

de.lmu.ifi.dbs.elki.utilities.datastructures.arraylike.ArrayLikeUtil

public final class ArrayLikeUtil
extends Object

Utility class that allows plug-in use of various "array-like" types such as lists in APIs that can take any kind of array to safe the cost of reorganizing the objects into a real array.

Field Summary

Fields

Modifier and Type	Field and Description
static ArrayDBIDsAdapter	ARRAYDBIDADAPTER Use ArrayDBIDs as array.
static NumberArrayAdapter<Double,double[]>	DOUBLEARRAYADAPTER Use a double array in the array API.
static FeatureVectorAdapter<?>	FEATUREVECTORADAPTER Static instance.
static NumberArrayAdapter<Float,float[]>	FLOATARRAYADAPTER Use a float array in the array API.
private static IdentityArrayAdapter<?>	IDENTITYADAPTER Static instance.
private static ListArrayAdapter<Object>	LISTADAPTER Static instance for lists.
private static NumberListArrayAdapter<Number>	NUMBERLISTADAPTER Static instance for lists of numbers.
static NumberVectorAdapter<?>	NUMBERVECTORADAPTER Use a number vector in the array API.
static TDoubleListAdapter	TDOUBLELISTADAPTER Use a Trove double list as array.

Constructor Summary

Constructors

Modifier	Constructor and Description
private	ArrayLikeUtil() Fake constructor.

Method Summary

Methods

Modifier and Type	Method and Description
static NumberArrayAdapter<Double,double[]>	doubleArrayAdapter() Get the adapter for double arrays.
static <F> FeatureVectorAdapter<F>	featureVectorAdapter(FeatureVector<F> prototype) Get the static instance.
static <A> int	getIndexOfMaximum(A array, NumberArrayAdapter<?,A> adapter) Returns the index of the maximum of the given values.
static int	getIndexOfMaximum(double[] array) Returns the index of the maximum of the given values.
static <T> IdentityArrayAdapter<T>	identityAdapter(T dummy) Get the static instance.
static <T> ArrayAdapter<T,List<? extends T>>	listAdapter(List<? extends T> dummy) Cast the static instance.
static <T extends Number> NumberArrayAdapter<T,List<? extends T>>	numberListAdapter(List<? extends T> dummy) Cast the static instance.
static <N extends Number> NumberVectorAdapter<N>	numberVectorAdapter(NumberVector<N> prototype) Get the static instance.
static <A> double[]	toPrimitiveDoubleArray(A array, NumberArrayAdapter<?,? super A> adapter) Convert a numeric array-like to a double[].
static double[]	toPrimitiveDoubleArray(List<? extends Number> array) Convert a list of numbers to double[].
static <N extends Number> double[]	toPrimitiveDoubleArray(NumberVector<N> obj) Convert a number vector to double[].
static <A> float[]	toPrimitiveFloatArray(A array, NumberArrayAdapter<?,? super A> adapter) Convert a numeric array-like to a float[].
static float[]	toPrimitiveFloatArray(List<? extends Number> array) Convert a list of numbers to float[].
static <N extends Number> float[]	toPrimitiveFloatArray(NumberVector<N> obj) Convert a number vector to float[].

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

LISTADAPTER

private static final ListArrayAdapter<Object> LISTADAPTER

Static instance for lists.

NUMBERLISTADAPTER

private static final NumberListArrayAdapter<Number> NUMBERLISTADAPTER

Static instance for lists of numbers.

IDENTITYADAPTER

private static final IdentityArrayAdapter<?> IDENTITYADAPTER

Static instance.

FEATUREVECTORADAPTER

public static final FeatureVectorAdapter<?> FEATUREVECTORADAPTER

Static instance.

NUMBERVECTORADAPTER

public static final NumberVectorAdapter<?> NUMBERVECTORADAPTER

Use a number vector in the array API.

DOUBLEARRAYADAPTER

public static final NumberArrayAdapter<Double,double[]> DOUBLEARRAYADAPTER

Use a double array in the array API.

FLOATARRAYADAPTER

public static final NumberArrayAdapter<Float,float[]> FLOATARRAYADAPTER

Use a float array in the array API.

TDOUBLELISTADAPTER

public static final TDoubleListAdapter TDOUBLELISTADAPTER

Use a Trove double list as array.

ARRAYDBIDADAPTER

public static final ArrayDBIDsAdapter ARRAYDBIDADAPTER

Use ArrayDBIDs as array.

Constructor Detail

ArrayLikeUtil

private ArrayLikeUtil()

Fake constructor. Do not instantiate!

Method Detail

listAdapter

public static <T> ArrayAdapter<T,List<? extends T>> listAdapter(List<? extends T> dummy)

Cast the static instance.

Parameters:

dummy - Dummy variable, for type inference

Returns:

Static instance

numberListAdapter

public static <T extends Number> NumberArrayAdapter<T,List<? extends T>> numberListAdapter(List<? extends T> dummy)

Cast the static instance.

Parameters:

dummy - Dummy variable, for type inference

Returns:

Static instance

identityAdapter

public static <T> IdentityArrayAdapter<T> identityAdapter(T dummy)

Get the static instance.

Parameters:

dummy - Dummy object for type inference

Returns:

Static instance

featureVectorAdapter

public static <F> FeatureVectorAdapter<F> featureVectorAdapter(FeatureVector<F> prototype)

Get the static instance.

Parameters:

prototype - Prototype value, for type inference

Returns:

Instance

numberVectorAdapter

public static <N extends Number> NumberVectorAdapter<N> numberVectorAdapter(NumberVector<N> prototype)

Get the static instance.

Parameters:

prototype - Prototype value, for type inference

Returns:

Instance

doubleArrayAdapter

public static NumberArrayAdapter<Double,double[]> doubleArrayAdapter()

Get the adapter for double arrays.

Returns:

double array adapter

getIndexOfMaximum

public static <A> int getIndexOfMaximum(A array,
                        NumberArrayAdapter<?,A> adapter)
                             throws IndexOutOfBoundsException

Returns the index of the maximum of the given values. If no value is bigger than the first, the index of the first entry is returned.

Type Parameters:

A - array type

Parameters:

array - Array to inspect

adapter - API adapter class

Returns:

the index of the maximum in the given values

Throws:

IndexOutOfBoundsException - if the length of the array is 0.

getIndexOfMaximum

public static int getIndexOfMaximum(double[] array)
                             throws IndexOutOfBoundsException

Returns the index of the maximum of the given values. If no value is bigger than the first, the index of the first entry is returned.

Parameters:

array - Array to inspect

Returns:

the index of the maximum in the given values

Throws:

IndexOutOfBoundsException - if the length of the array is 0.

toPrimitiveDoubleArray

public static <A> double[] toPrimitiveDoubleArray(A array,
                                  NumberArrayAdapter<?,? super A> adapter)

Convert a numeric array-like to a double[].

Parameters:

array - Array-like

adapter - Adapter

Returns:

primitive double array

toPrimitiveDoubleArray

public static double[] toPrimitiveDoubleArray(List<? extends Number> array)

Convert a list of numbers to double[].

Parameters:

array - List of numbers

Returns:

double array

toPrimitiveDoubleArray

public static <N extends Number> double[] toPrimitiveDoubleArray(NumberVector<N> obj)

Convert a number vector to double[].

Parameters:

obj - Object to convert

Returns:

primitive double array

toPrimitiveFloatArray

public static <A> float[] toPrimitiveFloatArray(A array,
                                NumberArrayAdapter<?,? super A> adapter)

Convert a numeric array-like to a float[].

Parameters:

array - Array-like

adapter - Adapter

Returns:

primitive float array

toPrimitiveFloatArray

public static float[] toPrimitiveFloatArray(List<? extends Number> array)

Convert a list of numbers to float[].

Parameters:

array - List of numbers

Returns:

float array

toPrimitiveFloatArray

public static <N extends Number> float[] toPrimitiveFloatArray(NumberVector<N> obj)

Convert a number vector to float[].

Parameters:

obj - Object to convert

Returns:

primitive float array