MathContext (Java Platform SE 6) (original) (raw)

java.math

Class MathContext

java.lang.Object java.math.MathContext

All Implemented Interfaces:

Serializable

public final class MathContext

extends Object

implements Serializable

Immutable objects which encapsulate the context settings which describe certain rules for numerical operators, such as those implemented by the BigDecimal class.

The base-independent settings are:

1. precision: the number of digits to be used for an operation; results are rounded to this precision
2. roundingMode: a RoundingMode object which specifies the algorithm to be used for rounding.

Since:

1.5

See Also:

BigDecimal, RoundingMode, Serialized Form

UNLIMITED

public static final MathContext UNLIMITED

A MathContext object whose settings have the values required for unlimited precision arithmetic. The values of the settings are: precision=0 roundingMode=HALF_UP

DECIMAL32

public static final MathContext DECIMAL32

A MathContext object with a precision setting matching the IEEE 754R Decimal32 format, 7 digits, and a rounding mode of HALF_EVEN, the IEEE 754R default.

DECIMAL64

public static final MathContext DECIMAL64

A MathContext object with a precision setting matching the IEEE 754R Decimal64 format, 16 digits, and a rounding mode of HALF_EVEN, the IEEE 754R default.

DECIMAL128

public static final MathContext DECIMAL128

A MathContext object with a precision setting matching the IEEE 754R Decimal128 format, 34 digits, and a rounding mode of HALF_EVEN, the IEEE 754R default.

MathContext

public MathContext(int setPrecision)

Constructs a new MathContext with the specified precision and the HALF_UP rounding mode.

Parameters:

setPrecision - The non-negative int precision setting.

Throws:

[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang") - if the setPrecision parameter is less than zero.

MathContext

public MathContext(int setPrecision, RoundingMode setRoundingMode)

Constructs a new MathContext with a specified precision and rounding mode.

Parameters:

setPrecision - The non-negative int precision setting.

setRoundingMode - The rounding mode to use.

Throws:

[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang") - if the setPrecision parameter is less than zero.

[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang") - if the rounding mode argument is null

MathContext

public MathContext(String val)

Constructs a new MathContext from a string. The string must be in the same format as that produced by thetoString() method.

An IllegalArgumentException is thrown if the precision section of the string is out of range (< 0) or the string is not in the format created by the toString() method.

Parameters:

val - The string to be parsed

Throws:

[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang") - if the precision section is out of range or of incorrect format

[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang") - if the argument is null

getPrecision

public int getPrecision()

Returns the precision setting. This value is always non-negative.

Returns:

an int which is the value of the precision setting

getRoundingMode

public RoundingMode getRoundingMode()

Returns the roundingMode setting. This will be one ofRoundingMode.CEILING,RoundingMode.DOWN,RoundingMode.FLOOR,RoundingMode.HALF_DOWN,RoundingMode.HALF_EVEN,RoundingMode.HALF_UP,RoundingMode.UNNECESSARY, orRoundingMode.UP.

Returns:

a RoundingMode object which is the value of theroundingMode setting

equals

public boolean equals(Object x)

Compares this MathContext with the specifiedObject for equality.

Overrides:

[equals](../../java/lang/Object.html#equals%28java.lang.Object%29) in class [Object](../../java/lang/Object.html "class in java.lang")

Parameters:

x - Object to which this MathContext is to be compared.

Returns:

true if and only if the specified Object is a MathContext object which has exactly the same settings as this object

See Also:

Object.hashCode(), Hashtable

hashCode

public int hashCode()

Returns the hash code for this MathContext.

Overrides:

[hashCode](../../java/lang/Object.html#hashCode%28%29) in class [Object](../../java/lang/Object.html "class in java.lang")

Returns:

hash code for this MathContext

See Also:

Object.equals(java.lang.Object), Hashtable

toString

public String toString()

Returns the string representation of this MathContext. The String returned represents the settings of theMathContext object as two space-delimited words (separated by a single space character, '\u0020', and with no leading or trailing white space), as follows:

1. The string "precision=", immediately followed by the value of the precision setting as a numeric string as if generated by the Integer.toString method.
2. The string "roundingMode=", immediately followed by the value of the roundingMode setting as a word. This word will be the same as the name of the corresponding public constant in the RoundingMode enum.

For example:

precision=9 roundingMode=HALF_UP

Additional words may be appended to the result oftoString in the future if more properties are added to this class.

Overrides:

[toString](../../java/lang/Object.html#toString%28%29) in class [Object](../../java/lang/Object.html "class in java.lang")

Returns:

a String representing the context settings

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For further API reference and developer documentation, see Java SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

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