ptolemy.data
Class FloatToken

java.lang.Object
  ptolemy.data.Token
      ptolemy.data.ScalarToken
          ptolemy.data.FloatToken

All Implemented Interfaces:

java.io.Serializable, BitwiseOperationToken

public class FloatToken
extends ScalarToken

A token that contains a 32-bit signed mantissa, signed exponent single precision floating-point number (IEEE 754). This class handles overflow and underflow as does normal java arithmetic on floats.

Note that a float cannot be losslessly converted to an int, and vice versa, as both have 32-bit representations in Java.

Since:

Ptolemy II 6.1

Version:

$Id: FloatToken.java 57040 2010-01-27 20:52:32Z cxh $

Author:

Ben Lickly; Based on DoubleToken by Neil Smyth, Yuhong Xiong, Christopher Hylands, Steve Neuendorffer

See Also:

Token, Serialized Form

Accepted Rating:

Red (blickly)

Proposed Rating:

Red (blickly) nil token, ONE, ZERO

Field Summary

private float	_value
static FloatToken	NIL A token that represents a missing value.
static FloatToken	ONE A FloatToken with the value 1.0.
static FloatToken	ZERO A FloatToken with the value 0.0.

Fields inherited from class ptolemy.data.ScalarToken

_unitCategoryExponents

Constructor Summary

FloatToken()
Construct a FloatToken with value 0.0.

FloatToken(float value)
Construct a FloatToken with the specified value.

FloatToken(java.lang.String init)
Construct a FloatToken from the specified string.

Method Summary

protected ScalarToken	_absolute() Return a ScalarToken containing the absolute value of the value of this token.
protected ScalarToken	_add(ScalarToken rightArgument) Return a new token whose value is the value of the argument Token added to the value of this Token.
protected ScalarToken	_bitwiseAnd(ScalarToken rightArgument) Returns a token representing the bitwise AND of this token and the given token.
protected ScalarToken	_bitwiseNot() Returns a token representing the bitwise NOT of this token.
protected ScalarToken	_bitwiseOr(ScalarToken rightArgument) Returns a token representing the bitwise OR of this token and the given token.
protected ScalarToken	_bitwiseXor(ScalarToken rightArgument) Returns a token representing the bitwise XOR of this token and the given token.
protected ScalarToken	_divide(ScalarToken divisor) Return a new token whose value is the value of this token divided by the value of the argument token.
protected BooleanToken	_isCloseTo(ScalarToken rightArgument, double epsilon) Test that the value of this token is close to the first argument, where "close" means that the distance between their values is less than or equal to the second argument.
protected BooleanToken	_isLessThan(ScalarToken rightArgument) Test for ordering of the values of this Token and the argument Token.
protected ScalarToken	_modulo(ScalarToken rightArgument) Return a new token whose value is the value of this token modulo the value of the argument token.
protected ScalarToken	_multiply(ScalarToken rightArgument) Return a new token whose value is the value of this token multiplied by the value of the argument token.
protected ScalarToken	_subtract(ScalarToken rightArgument) Return a new token whose value is the value of the argument token subtracted from the value of this token.
static FloatToken	convert(Token token) Convert the specified token into an instance of FloatToken.
double	doubleValue() Return the value in the token as a double.
boolean	equals(java.lang.Object object) Return true if the argument's class is FloatToken and it has the same values as this token.
float	floatValue() Return the value in the token as a flaot.
Type	getType() Return the type of this token.
int	hashCode() Return a hash code value for this token.
boolean	isNil() Return true if the token is nil, (aka null or missing).
Token	one() Returns a FloatToken with value 1.0.
java.lang.String	toString() Return the value of this token as a string that can be parsed by the expression language to recover a token with the same value.
Token	zero() Returns a FloatToken with value 0.0.

Methods inherited from class ptolemy.data.ScalarToken

_addCategoryExponents, _areUnitsEqual, _copyOfCategoryExponents, _isEqualTo, _isUnitless, _subtractCategoryExponents, absolute, add, addReverse, bitwiseAnd, bitwiseNot, bitwiseOr, bitwiseXor, byteValue, complexValue, divide, divideReverse, fixValue, intValue, inUnitsOf, isCloseTo, isEqualTo, isGreaterThan, isLessThan, leftShift, logicalRightShift, longValue, modulo, moduloReverse, multiply, multiplyReverse, rightShift, setUnitCategory, shortValue, subtract, subtractReverse, unitsString

Methods inherited from class ptolemy.data.Token

isCloseTo, notSupportedConversionMessage, notSupportedIncomparableConversionMessage, notSupportedIncomparableMessage, notSupportedMessage, notSupportedNullNilStringMessage, pow, zeroReturnType

Methods inherited from class java.lang.Object

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

Field Detail

NIL

public static final FloatToken NIL

A token that represents a missing value. Null or missing tokens are common in analytical systems like R and SAS where they are used to handle sparsely populated data sources. In database parlance, missing tokens are sometimes called null tokens. Since null is a Java keyword, we use the term "nil". The toString() method on a nil token returns the string "nil".

ONE

public static final FloatToken ONE

A FloatToken with the value 1.0.

ZERO

public static final FloatToken ZERO

A FloatToken with the value 0.0.

_value

private float _value

Constructor Detail

FloatToken

public FloatToken()

Construct a FloatToken with value 0.0.

FloatToken

public FloatToken(float value)

Construct a FloatToken with the specified value.

Parameters:

value - The specified value.

FloatToken

public FloatToken(java.lang.String init)
           throws IllegalActionException

Construct a FloatToken from the specified string.

Parameters:

init - The initialization string, which is in a format suitable for java.lang.Float.parseFloat(String).

Throws:

IllegalActionException - If the Token could not be created with the given String.

Method Detail

convert

public static FloatToken convert(Token token)
                          throws IllegalActionException

Convert the specified token into an instance of FloatToken. This method does lossless conversion. The units of the returned token will be the same as the units of the given token. If the argument is already an instance of FloatToken, it is returned without any change. If the argument is a nil token, then NIL is returned. Otherwise, if the argument is below FloatToken in the type hierarchy, it is converted to an instance of FloatToken or one of the subclasses of FloatToken and returned. If none of the above condition is met, an exception is thrown.

Parameters:

token - The token to be converted to a FloatToken.

Returns:

A FloatToken.

Throws:

IllegalActionException - If the conversion cannot be carried out.

doubleValue

public double doubleValue()

Return the value in the token as a double.

Overrides:

doubleValue in class ScalarToken

Returns:

The value contained in this token represented as a double.

equals

public boolean equals(java.lang.Object object)

Return true if the argument's class is FloatToken and it has the same values as this token.

Overrides:

equals in class java.lang.Object

Parameters:

object - An instance of Object.

Returns:

True if the argument is a FloatToken with the same value. If either this object or the argument is a nil Token, return false.

floatValue

public float floatValue()

Return the value in the token as a flaot.

Overrides:

floatValue in class ScalarToken

Returns:

The value contained in this token as a float.

getType

public Type getType()

Return the type of this token.

Specified by:

getType in class ScalarToken

Returns:

BaseType.FLOAT

hashCode

public int hashCode()

Return a hash code value for this token. This method returns the integer portion of the contained float.

Overrides:

hashCode in class java.lang.Object

Returns:

A hash code value for this token.

isNil

public boolean isNil()

Return true if the token is nil, (aka null or missing). Nil or missing tokens occur when a data source is sparsely populated.

Overrides:

isNil in class Token

Returns:

True if the token is the NIL token.

one

public Token one()

Returns a FloatToken with value 1.0.

Overrides:

one in class Token

Returns:

A FloatToken with value 1.0.

toString

public java.lang.String toString()

Return the value of this token as a string that can be parsed by the expression language to recover a token with the same value. The exact form of the number depends on its value, and may be either decimal or exponential. In general, exponential is used for numbers whose magnitudes are very large or very small, except for zero which is always represented as 0.0. The behavior is roughly the same as Float.toString(), except that we limit the precision to seven fractional digits. If you really must have better precision, then use Float.toString(token.floatValue()). If this token has a unit, the return string also includes a unit string produced by the unitsString() method in the super class.

Overrides:

toString in class Token

Returns:

A String representing the float value and the units (if any) of this token.

See Also:

ScalarToken.unitsString()

zero

public Token zero()

Returns a FloatToken with value 0.0.

Overrides:

zero in class Token

Returns:

A FloatToken with value 0.0.

_absolute

protected ScalarToken _absolute()

Return a ScalarToken containing the absolute value of the value of this token. If this token contains a non-negative number, it is returned directly; otherwise, a new token is is return. Note that it is explicitly allowable to return this token, since the units are the same.

Specified by:

_absolute in class ScalarToken

Returns:

An FloatToken.

_add

protected ScalarToken _add(ScalarToken rightArgument)

Return a new token whose value is the value of the argument Token added to the value of this Token. It is assumed that the type of the argument is a FloatToken.

Specified by:

_add in class ScalarToken

Parameters:

rightArgument - The token to add to this token.

Returns:

A new FloatToken containing the result.

_bitwiseAnd

protected ScalarToken _bitwiseAnd(ScalarToken rightArgument)
                           throws IllegalActionException

Returns a token representing the bitwise AND of this token and the given token.

Specified by:

_bitwiseAnd in class ScalarToken

Parameters:

rightArgument - The FloatToken to bitwise AND with this one.

Returns:

The bitwise AND.

Throws:

IllegalActionException - Always thrown by this base class.

_bitwiseNot

protected ScalarToken _bitwiseNot()
                           throws IllegalActionException

Returns a token representing the bitwise NOT of this token.

Specified by:

_bitwiseNot in class ScalarToken

Returns:

The bitwise NOT of this token.

Throws:

IllegalActionException - Always thrown by this base class.

_bitwiseOr

protected ScalarToken _bitwiseOr(ScalarToken rightArgument)
                          throws IllegalActionException

Returns a token representing the bitwise OR of this token and the given token.

Specified by:

_bitwiseOr in class ScalarToken

Parameters:

rightArgument - The FloatToken to bitwise OR with this one.

Returns:

The bitwise OR.

Throws:

IllegalActionException - Always thrown by this base class.

_bitwiseXor

protected ScalarToken _bitwiseXor(ScalarToken rightArgument)
                           throws IllegalActionException

Returns a token representing the bitwise XOR of this token and the given token.

Specified by:

_bitwiseXor in class ScalarToken

Parameters:

rightArgument - The FloatToken to bitwise XOR with this one.

Returns:

The bitwise XOR.

Throws:

IllegalActionException - Always thrown by this base class.

_divide

protected ScalarToken _divide(ScalarToken divisor)

Return a new token whose value is the value of this token divided by the value of the argument token. It is assumed that the type of the argument is a FloatToken

Specified by:

_divide in class ScalarToken

Parameters:

divisor - The token to divide this token by.

Returns:

A new FloatToken containing the result.

_isCloseTo

protected BooleanToken _isCloseTo(ScalarToken rightArgument,
                                  double epsilon)

Test that the value of this token is close to the first argument, where "close" means that the distance between their values is less than or equal to the second argument. It is assumed that the type of the first argument is FloatToken.

Specified by:

_isCloseTo in class ScalarToken

Parameters:

rightArgument - The token to compare to this token.

epsilon - The distance.

Returns:

A token containing tue if the value of this token is close to that of the argument.

_isLessThan

protected BooleanToken _isLessThan(ScalarToken rightArgument)
                            throws IllegalActionException

Test for ordering of the values of this Token and the argument Token. It is assumed that the type of the argument is FloatToken.

Specified by:

_isLessThan in class ScalarToken

Parameters:

rightArgument - The token to compare to this token.

Returns:

A new Token containing the result.

Throws:

IllegalActionException - If this method is not supported by the derived class.

_modulo

protected ScalarToken _modulo(ScalarToken rightArgument)

Return a new token whose value is the value of this token modulo the value of the argument token. It is assumed that the type of the argument is a FloatToken.

Specified by:

_modulo in class ScalarToken

Parameters:

rightArgument - The token to modulo this token by.

Returns:

A new FloatToken containing the result.

_multiply

protected ScalarToken _multiply(ScalarToken rightArgument)

Return a new token whose value is the value of this token multiplied by the value of the argument token. It is assumed that the type of the argument is a FloatToken.

Specified by:

_multiply in class ScalarToken

Parameters:

rightArgument - The token to multiply this token by.

Returns:

A new FloatToken containing the result.

_subtract

protected ScalarToken _subtract(ScalarToken rightArgument)

Return a new token whose value is the value of the argument token subtracted from the value of this token. It is assumed that the type of the argument is a FloatToken.

Specified by:

_subtract in class ScalarToken

Parameters:

rightArgument - The token to subtract from this token.

Returns:

A new FloatToken containing the result.