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 java.lang.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.

Since:

0.5.0

Author:

Erich Schubert

Field Summary

Fields

Modifier and Type	Field and Description
static NumberArrayAdapter<java.lang.Double,double[]>	DOUBLEARRAYADAPTER Use a double array in the array API.
static FeatureVectorAdapter<?>	FEATUREVECTORADAPTER Static instance.
static NumberArrayAdapter<java.lang.Float,float[]>	FLOATARRAYADAPTER Use a float array in the array API.
private static ListArrayAdapter<java.lang.Object>	LISTADAPTER Static instance for lists.
private static NumberListArrayAdapter<java.lang.Number>	NUMBERLISTADAPTER Static instance for lists of numbers.
static NumberVectorAdapter	NUMBERVECTORADAPTER Use a number vector in the array API.

Constructor Summary

Constructors

Modifier	Constructor and Description
private	ArrayLikeUtil() Fake constructor.

Method Summary

Modifier and Type	Method and Description
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> ArrayAdapter<T,java.util.List<? extends T>>	listAdapter(java.util.List<? extends T> dummy) Cast the static instance.
static <T extends java.lang.Number> NumberArrayAdapter<T,java.util.List<? extends T>>	numberListAdapter(java.util.List<? extends T> dummy) Cast the static instance.
static <A> double[]	toPrimitiveDoubleArray(A array, NumberArrayAdapter<?,? super A> adapter) Convert a numeric array-like to a double[].
static double[]	toPrimitiveDoubleArray(java.util.List<? extends java.lang.Number> array) Convert a list of numbers to double[].
static double[]	toPrimitiveDoubleArray(NumberVector 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(java.util.List<? extends java.lang.Number> array) Convert a list of numbers to float[].
static float[]	toPrimitiveFloatArray(NumberVector obj) Convert a number vector to float[].
static <A> int[]	toPrimitiveIntegerArray(A array, NumberArrayAdapter<?,? super A> adapter) Convert a numeric array-like to a int[].
static int[]	toPrimitiveIntegerArray(java.util.List<? extends java.lang.Number> array) Convert a list of numbers to int[].
static int[]	toPrimitiveIntegerArray(NumberVector obj) Convert a number vector to int[].

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<java.lang.Object> LISTADAPTER

Static instance for lists.

NUMBERLISTADAPTER

private static final NumberListArrayAdapter<java.lang.Number> NUMBERLISTADAPTER

Static instance for lists of numbers.

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<java.lang.Double,double[]> DOUBLEARRAYADAPTER

Use a double array in the array API.

FLOATARRAYADAPTER

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

Use a float array in the array API.

Constructor Detail

ArrayLikeUtil

private ArrayLikeUtil()

Fake constructor. Do not instantiate!

Method Detail

listAdapter

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

Cast the static instance.

Parameters:

dummy - Dummy variable, for type inference

Returns:

Static instance

numberListAdapter

public static <T extends java.lang.Number> NumberArrayAdapter<T,java.util.List<? extends T>> numberListAdapter(java.util.List<? extends T> dummy)

Cast the static instance.

Parameters:

dummy - Dummy variable, 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

getIndexOfMaximum

public static <A> int getIndexOfMaximum(A array,
                                        NumberArrayAdapter<?,A> adapter)
                                 throws java.lang.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:

java.lang.IndexOutOfBoundsException - if the length of the array is 0.

getIndexOfMaximum

public static int getIndexOfMaximum(double[] array)
                             throws java.lang.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:

java.lang.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(java.util.List<? extends java.lang.Number> array)

Convert a list of numbers to double[].

Parameters:

array - List of numbers

Returns:

double array

toPrimitiveDoubleArray

public static double[] toPrimitiveDoubleArray(NumberVector 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(java.util.List<? extends java.lang.Number> array)

Convert a list of numbers to float[].

Parameters:

array - List of numbers

Returns:

float array

toPrimitiveFloatArray

public static float[] toPrimitiveFloatArray(NumberVector obj)

Convert a number vector to float[].

Parameters:

obj - Object to convert

Returns:

primitive float array

toPrimitiveIntegerArray

public static <A> int[] toPrimitiveIntegerArray(A array,
                                                NumberArrayAdapter<?,? super A> adapter)

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

Parameters:

array - Array-like

adapter - Adapter

Returns:

primitive double array

toPrimitiveIntegerArray

public static int[] toPrimitiveIntegerArray(java.util.List<? extends java.lang.Number> array)

Convert a list of numbers to int[].

Parameters:

array - List of numbers

Returns:

double array

toPrimitiveIntegerArray

public static int[] toPrimitiveIntegerArray(NumberVector obj)

Convert a number vector to int[].

Parameters:

obj - Object to convert

Returns:

primitive double array