java.math

Class MathContext

java.lang.Object

java.math.MathContext

All Implemented Interfaces:

Serializable

public final class MathContext
extends Object
implements Serializable

Immutable objects describing settings such as rounding mode and digit precision for the numerical operations provided by class BigDecimal.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static MathContext	DECIMAL128 A MathContext which corresponds to the IEEE 754 quadruple decimal precision format: 34 digit precision and RoundingMode.HALF_EVEN rounding.
static MathContext	DECIMAL32 A MathContext which corresponds to the IEEE 754 single decimal precision format: 7 digit precision and RoundingMode.HALF_EVEN rounding.
static MathContext	DECIMAL64 A MathContext which corresponds to the IEEE 754 double decimal precision format: 16 digit precision and RoundingMode.HALF_EVEN rounding.
static MathContext	UNLIMITED A MathContext for unlimited precision with RoundingMode.HALF_UP rounding.

Constructor Summary

Constructors

Constructor and Description
MathContext(int precision) Constructs a new MathContext with the specified precision and with the rounding mode HALF_UP.
MathContext(int precision, RoundingMode roundingMode) Constructs a new MathContext with the specified precision and with the specified rounding mode.
MathContext(String s) Constructs a new MathContext from a string.

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object x) Returns true if x is a MathContext with the same precision setting and the same rounding mode as this MathContext instance.
int	getPrecision() Returns the precision.
RoundingMode	getRoundingMode() Returns the rounding mode.
int	hashCode() Returns the hash code for this MathContext instance.
String	toString() Returns the string representation for this MathContext instance.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

DECIMAL128

public static final MathContext DECIMAL128

A MathContext which corresponds to the IEEE 754 quadruple decimal precision format: 34 digit precision and RoundingMode.HALF_EVEN rounding.

DECIMAL32

public static final MathContext DECIMAL32

A MathContext which corresponds to the IEEE 754 single decimal precision format: 7 digit precision and RoundingMode.HALF_EVEN rounding.

DECIMAL64

public static final MathContext DECIMAL64

A MathContext which corresponds to the IEEE 754 double decimal precision format: 16 digit precision and RoundingMode.HALF_EVEN rounding.

UNLIMITED

public static final MathContext UNLIMITED

A MathContext for unlimited precision with RoundingMode.HALF_UP rounding.

Constructor Detail

MathContext

public MathContext(int precision)

Constructs a new MathContext with the specified precision and with the rounding mode HALF_UP. If the precision passed is zero, then this implies that the computations have to be performed exact, the rounding mode in this case is irrelevant.

Parameters:

precision - the precision for the new MathContext.

Throws:

IllegalArgumentException - if precision < 0.

MathContext

public MathContext(int precision,
                   RoundingMode roundingMode)

Constructs a new MathContext with the specified precision and with the specified rounding mode. If the precision passed is zero, then this implies that the computations have to be performed exact, the rounding mode in this case is irrelevant.

Parameters:

precision - the precision for the new MathContext.

roundingMode - the rounding mode for the new MathContext.

Throws:

IllegalArgumentException - if precision < 0.

NullPointerException - if roundingMode is null.

MathContext

public MathContext(String s)

Constructs a new MathContext from a string. The string has to specify the precision and the rounding mode to be used and has to follow the following syntax: "precision=<precision> roundingMode=<roundingMode>" This is the same form as the one returned by the toString() method.

Throws:

IllegalArgumentException - if the string is not in the correct format or if the precision specified is < 0.

Method Detail

getPrecision

public int getPrecision()

Returns the precision. The precision is the number of digits used for an operation. Results are rounded to this precision. The precision is guaranteed to be non negative. If the precision is zero, then the computations have to be performed exact, results are not rounded in this case.

Returns:

the precision.

getRoundingMode

public RoundingMode getRoundingMode()

Returns the rounding mode. The rounding mode is the strategy to be used to round results.

The rounding mode is one of RoundingMode.UP, RoundingMode.DOWN, RoundingMode.CEILING, RoundingMode.FLOOR, RoundingMode.HALF_UP, RoundingMode.HALF_DOWN, RoundingMode.HALF_EVEN, or RoundingMode.UNNECESSARY.

Returns:

the rounding mode.

equals

public boolean equals(Object x)

Returns true if x is a MathContext with the same precision setting and the same rounding mode as this MathContext instance.

Overrides:

equals in class Object

Parameters:

x - object to be compared.

Returns:

true if this MathContext instance is equal to the x argument; false otherwise.

See Also:

Object.hashCode()

hashCode

public int hashCode()

Returns the hash code for this MathContext instance.

Overrides:

hashCode in class Object

Returns:

the hash code for this MathContext.

See Also:

Object.equals(java.lang.Object)

toString

public String toString()

Returns the string representation for this MathContext instance. The string has the form "precision=<precision> roundingMode=<roundingMode>" where <precision> is an integer describing the number of digits used for operations and <roundingMode> is the string representation of the rounding mode.

Overrides:

toString in class Object

Returns:

a string representation for this MathContext instance