org.geotoolkit.util.converter
Class Numbers

Object
  Static
      Numbers

public final class Numbers
extends Static

Miscellaneous static methods working on Number objects, and a few primitive types by extension.

Since:

3.18 (derived from 2.5)

Version:

3.18

Author:

Martin Desruisseaux (IRD, Geomatys)

Module:

utility/geotk-utility (download)

View source code for this class

Field Summary

static byte	BOOLEAN Constants to be used in switch statements.
static byte	BYTE Constants to be used in switch statements.
static byte	CHARACTER Constants to be used in switch statements.
static byte	DOUBLE Constants to be used in switch statements.
static byte	FLOAT Constants to be used in switch statements.
static byte	INTEGER Constants to be used in switch statements.
static byte	LONG Constants to be used in switch statements.
static byte	OTHER Constants to be used in switch statements.
static byte	SHORT Constants to be used in switch statements.

Method Summary

static <N extends Number> N	cast(Number n, Class<N> c) Casts a number to the specified class.
static Class<? extends Number>	finestClass(Class<? extends Number> c1, Class<? extends Number> c2) Returns the finest of the given types.
static Class<? extends Number>	finestClass(double value) Returns the smallest class capable to hold the specified value.
static Class<? extends Number>	finestClass(long value) Returns the smallest class capable to hold the specified value.
static Class<? extends Number>	finestClass(Number value) Returns the smallest class capable to hold the specified value.
static Class<? extends Number>	finestClass(Number n1, Number n2) Returns the finest type of two numbers.
static Number	finestNumber(double value) Returns the number of the smallest class capable to hold the specified value.
static Number	finestNumber(long value) Returns the number of the smallest type capable to hold the specified value.
static Number	finestNumber(Number value) Returns the number of the smallest class capable to hold the specified value.
static Number	finestNumber(String value) Returns the smallest number capable to hold the specified value.
static byte	getEnumConstant(Class<?> type) Returns one of DOUBLE, FLOAT, LONG, INTEGER, SHORT, BYTE, CHARACTER, BOOLEAN or OTHER constants for the given type.
static boolean	isFloat(Class<?> type) Returns true if the given type is a floating point type.
static boolean	isInteger(Class<?> type) Returns true if the given type is an integer type.
static int	primitiveBitCount(Class<?> type) Returns the number of bits used by primitive of the specified type.
static Class<?>	primitiveToWrapper(Class<?> type) Changes a primitive class to its wrapper (for example int to Integer).
static <T> T	valueOf(Class<T> type, String value) Converts the specified string into a value object.
static <T> T	valueOfNil(Class<T> type) Returns a NaN, zero, empty or null value of the given type.
static Class<? extends Number>	widestClass(Class<? extends Number> c1, Class<? extends Number> c2) Returns the widest of the given types.
static Class<? extends Number>	widestClass(Number n1, Number n2) Returns the widest type of two numbers.
static Class<?>	wrapperToPrimitive(Class<?> type) Changes a wrapper class to its primitive (for example Integer to int).

Methods inherited from class Object

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

Field Detail

DOUBLE

public static final byte DOUBLE

Constants to be used in switch statements.

See Also:

Constant Field Values

FLOAT

public static final byte FLOAT

Constants to be used in switch statements.

See Also:

Constant Field Values

LONG

public static final byte LONG

Constants to be used in switch statements.

See Also:

Constant Field Values

INTEGER

public static final byte INTEGER

Constants to be used in switch statements.

See Also:

Constant Field Values

SHORT

public static final byte SHORT

Constants to be used in switch statements.

See Also:

Constant Field Values

BYTE

public static final byte BYTE

Constants to be used in switch statements.

See Also:

Constant Field Values

CHARACTER

public static final byte CHARACTER

Constants to be used in switch statements.

See Also:

Constant Field Values

BOOLEAN

public static final byte BOOLEAN

Constants to be used in switch statements.

See Also:

Constant Field Values

OTHER

public static final byte OTHER

Constants to be used in switch statements.

See Also:

Constant Field Values

Method Detail

isFloat

public static boolean isFloat(Class<?> type)

Returns true if the given type is a floating point type.

Parameters:

type - The type to test (may be null).

Returns:

true if type is the primitive or wrapper class of Float or Double.

See Also:

isInteger(Class)

isInteger

public static boolean isInteger(Class<?> type)

Returns true if the given type is an integer type. The integer types are Long, long, Integer, int, Short, short, Byte, byte and BigInteger.

Parameters:

type - The type to test (may be null).

Returns:

true if type is an integer type.

See Also:

isFloat(Class)

primitiveBitCount

public static int primitiveBitCount(Class<?> type)
                             throws IllegalArgumentException

Returns the number of bits used by primitive of the specified type. The given type must be a primitive type or its wrapper class.

Parameters:

type - The primitive type (may be null).

Returns:

The number of bits, or 0 if type is null.

Throws:

IllegalArgumentException - if the given type is unknown.

primitiveToWrapper

public static Class<?> primitiveToWrapper(Class<?> type)

Changes a primitive class to its wrapper (for example int to Integer). If the specified class is not a primitive type, then it is returned unchanged.

Parameters:

type - The primitive type (may be null).

Returns:

The type as a wrapper.

See Also:

wrapperToPrimitive(Class)

wrapperToPrimitive

public static Class<?> wrapperToPrimitive(Class<?> type)

Changes a wrapper class to its primitive (for example Integer to int). If the specified class is not a wrapper type, then it is returned unchanged.

Parameters:

type - The wrapper type (may be null).

Returns:

The type as a primitive.

See Also:

primitiveToWrapper(Class)

widestClass

public static Class<? extends Number> widestClass(Number n1,
                                                  Number n2)
                                           throws IllegalArgumentException

Returns the widest type of two numbers. Numbers n1 and n2 can be instance of Byte, Short, Integer, Long, Float, Double, BigInteger or BigDecimal types.

If one of the given argument is null, then this method returns the class of the non-null argument. If both arguments are null, then this method returns null.

Parameters:

n1 - The first number, or null.

n2 - The second number, or null.

Returns:

The widest type of the given numbers, or null if not n1 and n2 are null.

Throws:

IllegalArgumentException - If a number is not of a known type.

See Also:

widestClass(Number, Number), finestClass(Number, Number)

widestClass

public static Class<? extends Number> widestClass(Class<? extends Number> c1,
                                                  Class<? extends Number> c2)
                                           throws IllegalArgumentException

Returns the widest of the given types. Classes c1 and c2 can be Byte, Short, Integer, Long, Float, Double, BigInteger or BigDecimal types.

If one of the given argument is null, then this method returns the non-null argument. If both arguments are null, then this method returns null.

Example:

widestClass(Short.class, Long.class);

returns Long.class.

Parameters:

c1 - The first number type, or null.

c2 - The second number type, or null.

Returns:

The widest of the given types, or null if both c1 and c2 are null.

Throws:

IllegalArgumentException - If one of the given types is unknown.

See Also:

widestClass(Class, Class), finestClass(Number, Number)

finestClass

public static Class<? extends Number> finestClass(Number n1,
                                                  Number n2)
                                           throws IllegalArgumentException

Returns the finest type of two numbers. Numbers n1 and n2 must be instance of any of Byte, Short, Integer, Long, Float Double, BigInteger or BigDecimal types.

Parameters:

n1 - The first number.

n2 - The second number.

Returns:

The finest type of the given numbers.

Throws:

IllegalArgumentException - If a number is not of a known type.

See Also:

finestClass(Class, Class), widestClass(Class, Class)

finestClass

public static Class<? extends Number> finestClass(Class<? extends Number> c1,
                                                  Class<? extends Number> c2)
                                           throws IllegalArgumentException

Returns the finest of the given types. Classes c1 and c2 can be Byte, Short, Integer, Long, Float, Double, BigInteger or BigDecimal types.

If one of the given argument is null, then this method returns the non-null argument. If both arguments are null, then this method returns null.

Example:

finestClass(Short.class, Long.class);

returns Short.class.

Parameters:

c1 - The first number type, or null.

c2 - The second number type, or null.

Returns:

The finest of the given types, or null if both c1 and c2 are null.

Throws:

IllegalArgumentException - If one of the given types is unknown.

See Also:

finestClass(Number, Number), widestClass(Class, Class)

finestClass

public static Class<? extends Number> finestClass(Number value)

Returns the smallest class capable to hold the specified value. If the given value is null, then this method returns null. Otherwise this method delegates to finestClass(double) or finestClass(long) depending on the value type.

Parameters:

value - The value to be wrapped in a finer (if possible) Number.

Returns:

The finest type capable to hold the given value.

Since:

3.06

See Also:

finestNumber(Number)

finestClass

public static Class<? extends Number> finestClass(double value)

Returns the smallest class capable to hold the specified value. This is similar to finestClass(long), but extended to floating point values.

Parameters:

value - The value to be wrapped in a Number.

Returns:

The finest type capable to hold the given value.

See Also:

finestNumber(double)

finestClass

public static Class<? extends Number> finestClass(long value)

Returns the smallest class capable to hold the specified value. This method makes the following choice:

• If the given value is between -128 and 127, then this method returns Byte.class;
• If the given value is between -32768 and 32767, then this method returns Short.class;
• If the given value is between -2147483648 and 2147483647, then this method returns Integer.class;
• Otherwise this method returns Long.class;

Parameters:

value - The value to be wrapped in a Number.

Returns:

The finest type capable to hold the given value.

Since:

3.00

See Also:

finestNumber(long)

finestNumber

public static Number finestNumber(Number value)

Returns the number of the smallest class capable to hold the specified value. If the given value is null, then this method returns null. Otherwise this method delegates to finestNumber(double) or finestNumber(long) depending on the value type.

Parameters:

value - The value to be wrapped in a finer (if possible) Number.

Returns:

The finest type capable to hold the given value.

Since:

3.06

See Also:

finestClass(Number)

finestNumber

public static Number finestNumber(double value)

Returns the number of the smallest class capable to hold the specified value. This is similar to finestNumber(long), but extended to floating point values.

Parameters:

value - The value to be wrapped in a Number.

Returns:

The finest type capable to hold the given value.

See Also:

finestClass(double)

finestNumber

public static Number finestNumber(long value)

Returns the number of the smallest type capable to hold the specified value. This method makes the following choice:

• If the given value is between -128 and 127, then it is wrapped in a Byte object.
• If the given value is between -32768 and 32767, then it is wrapped in a Short object.
• If the given value is between -2147483648 and 2147483647, then it is wrapped in an Integer object.
• Otherwise the value is wrapped in a Long object.

Parameters:

value - The value to be wrapped in a Number.

Returns:

The given value as a number of the finest type capable to hold it.

Since:

3.00

See Also:

finestClass(long)

finestNumber

public static Number finestNumber(String value)
                           throws NumberFormatException

Returns the smallest number capable to hold the specified value.

Parameters:

value - The value to be wrapped in a Number.

Returns:

The finest type capable to hold the given value.

Throws:

NumberFormatException - if the given value can not be parsed as a number.

Since:

3.00

See Also:

finestNumber(Number), finestNumber(double), finestNumber(long)

cast

public static <N extends Number> N cast(Number n,
                                        Class<N> c)
                             throws IllegalArgumentException

Casts a number to the specified class. The class must by one of Byte, Short, Integer, Long, Float or Double. This method makes the following choice:

• If the given type is Double.class, then this method returns Double.valueOf(n.doubleValue());
• If the given type is Float.class, then this method returns Float.valueOf(n.floatValue());
• And likewise for all remaining known types.

Note: This method is intentionally restricted to primitive types. Other types like BigDecimal are not the purpose of this method. See the ConverterRegistry class for a more generic method.

Type Parameters:

N - The class to cast to.

Parameters:

n - The number to cast.

c - The destination type.

Returns:

The number casted to the given type.

Throws:

IllegalArgumentException - If the given type is unknown.

valueOf

public static <T> T valueOf(Class<T> type,
                            String value)
                 throws IllegalArgumentException,
                        NumberFormatException

Converts the specified string into a value object. The value object can be an instance of Double, Float, Long, Integer, Short, Byte, Boolean, Character or String according the specified type. This method makes the following choice:

• If the given type is Double.class, then this method returns Double.valueOf(value);
• If the given type is Float.class, then this method returns Float.valueOf(value);
• And likewise for all remaining known types.

Note: This method is intentionally restricted to primitive types, with the addition of String which can be though as an identity operation. Other types like BigDecimal are not the purpose of this method. See the ConverterRegistry class for a more generic method.

Type Parameters:

T - The requested type.

Parameters:

type - The requested type.

value - the value to parse.

Returns:

The value object, or null if value was null.

Throws:

IllegalArgumentException - if type is not a recognized type.

NumberFormatException - if type is a subclass of Number and the string value is not parseable as a number of the specified type.

valueOfNil

public static <T> T valueOfNil(Class<T> type)

Returns a NaN, zero, empty or null value of the given type. This method tries to return the closest value that can be interpreted as "none", which is usually not the same than "zero". More specifically:

• If the given type is a floating point primitive type ({code float} or double), then this method returns Float.NaN or Double.NaN depending on the given type.
• If the given type is an integer primitive type or the character type (long, int, short, byte or char), then this method returns the zero value of the given type.
• If the given type is the boolean primitive type, then this method returns Boolean.FALSE.
• If the given type is an array or a collection, then this method returns an empty array or collection. The given type is honored on a best effort basis.
• For all other cases, including the wrapper classes of primitive types, this method returns null.

Despite being defined in the Numbers class, the scope of this method has been extended to array and collection types because those types can also be seen as mathematical objects.

Type Parameters:

T - The compile-time type of the requested object.

Parameters:

type - The type of the object for which to get a nil value.

Returns:

An object of the given type which represents a nil value, or null.

Since:

3.18

getEnumConstant

public static byte getEnumConstant(Class<?> type)

Returns one of DOUBLE, FLOAT, LONG, INTEGER, SHORT, BYTE, CHARACTER, BOOLEAN or OTHER constants for the given type. This is a commodity for usage in switch statements.

Parameters:

type - A type (usually either a primitive type or its wrapper).

Returns:

The constant for the given type, or OTHER if unknown.