org.foray.fotree.value
Class DtFrequency

java.lang.Object
  org.foray.fotree.value.Expr
      org.foray.fotree.value.ExprAdditive
          org.foray.fotree.value.ExprMultiplicative
              org.foray.fotree.value.ExprUnary
                  org.foray.fotree.value.ExprPrimary
                      org.foray.fotree.value.Datatype
                          org.foray.fotree.value.DtFrequency

All Implemented Interfaces:

PropertyValue

public class DtFrequency
extends Datatype

A "frequency" datatype in XSL. See XSL-FO Specification 1.0, Section 5.11.

Field Summary

static byte	UNITS_HERTZ Constant indicating a unit type of hertz.
static byte	UNITS_KILOHERTZ Constant indicating a unit type of kilohertz.

Fields inherited from class org.foray.fotree.value.Expr

OPERATION_ADD, OPERATION_DIVIDE, OPERATION_MOD, OPERATION_MULTIPLY, OPERATION_NEGATION, OPERATION_SUBTRACT, UNIT_POWER_AREA, UNIT_POWER_LENGTH, UNIT_POWER_NON_NUMERIC, UNIT_POWER_NUMERIC

Constructor Summary

DtFrequency(double quantity, byte units)
Constructor.

Method Summary

boolean	canEvalColor() Indicates whether this property value has the ability to express itself as a Color.
boolean	canEvalInteger() Indicates whether this property value has the ability to express itself as an integer Numeric item.
boolean	canEvalKeyword() Indicates whether this property value can evaluate to a keyword.
boolean	canEvalLength() Indicates whether this expression can be evaluated to a unit power = 1 (length) or not.
boolean	canEvalNumeric() Indicates whether this property value has the ability to express itself as a Numeric item.
boolean	canEvalPercentage() Indicates whether this property value can evaluate to a percentage.
Color	evalColor() Return the color value of "this".
int	evalInteger() Return this value as an int.
PvKeyword	evalKeyword() Returns the keyword value of this property value.
int	evalLength(int pointSize) Evaluates the expression to a unit power of 1 (length).
double	evalNumeric() Return the raw numeric value of "this", without regard to unit power.
float	evalPercentage() Returns the percentage value of this property value.
byte	getUnitPower() Each numeric has a "unit power".
double	getValue() Returns the value, normalized to a unit of Hertz.
boolean	lengthRequiresFontSize() Indicates whether the computation of the length will require an accurate font-size parameter.
static DtFrequency	makeFrequencyDT(String input) Factory method for creating a FrequencyDT from a String input.

Methods inherited from class org.foray.fotree.value.Datatype

convertValueToFoValue

Methods inherited from class org.foray.fotree.value.Expr

evalColorException, evalIntegerException, evalKeywordException, evalLengthException, evalNumericException, evalPercentageException

Methods inherited from class java.lang.Object

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

Field Detail

UNITS_HERTZ

public static final byte UNITS_HERTZ

Constant indicating a unit type of hertz.

See Also:

Constant Field Values

UNITS_KILOHERTZ

public static final byte UNITS_KILOHERTZ

Constant indicating a unit type of kilohertz.

See Also:

Constant Field Values

Constructor Detail

DtFrequency

public DtFrequency(double quantity,
                   byte units)
            throws PropertyException

Constructor.

Parameters:

quantity - The quantity of units.

units - The unit type, either UNITS_HERTZ or UNITS_KILOHERTZ.

Throws:

PropertyException - For an invalid units value.

Method Detail

getValue

public double getValue()

Returns the value, normalized to a unit of Hertz.

Returns:

The value, normalized to a unit of Hertz.

makeFrequencyDT

public static DtFrequency makeFrequencyDT(String input)

Factory method for creating a FrequencyDT from a String input.

Parameters:

input - The String from which a FrequencyDT should be constructed.

Returns:

The FrequencyDT instance constructed, or null if input is not valid.

canEvalNumeric

public boolean canEvalNumeric()

Description copied from interface: PropertyValue

Indicates whether this property value has the ability to express itself as a Numeric item.

Returns:

True iff this property value is a numeric.

evalNumeric

public double evalNumeric()

Description copied from interface: PropertyValue

Return the raw numeric value of "this", without regard to unit power.

Returns:

A double representation of the value of "this". Type "double" is assumed to be the lowest-common-denominator of all numeric values.

canEvalLength

public boolean canEvalLength()

Description copied from interface: PropertyValue

Indicates whether this expression can be evaluated to a unit power = 1 (length) or not.

Returns:

True if the expression can be evaluated to a unit power of 1 (length).

getUnitPower

public byte getUnitPower()

Description copied from interface: PropertyValue

Each numeric has a "unit power". This number refers to the number of spatial dimensions in which the number operates. So, a number that has no relationship to space or refers to a point, has a length power of 0. A number that refers to length has a length power of 1 (1 dimension). Although there are none yet in XSL-FO, a number that referred to area (e.g. square inches) would, we suppose, have a length power of 2, and one referring to volume (e.g. cubic feet) would, we suppose have a length power of 3.

Returns:

The number of spatial dimensions in which this numeric item operates. For XSL-FO items, this should be either Expr.UNIT_POWER_NUMERIC or Expr.UNIT_POWER_LENGTH.

evalLength

public int evalLength(int pointSize)

Description copied from interface: PropertyValue

Evaluates the expression to a unit power of 1 (length).

Parameters:

pointSize - The point size, in millipoints, of the font. This is used in calculations that are relative to the point size. In cases where the computation of the font-size is expensive, check PropertyValue.lengthRequiresFontSize() first. If that method returns false, zero or some other constant can safely be passed, as it will be ignored anyway.

Returns:

The unit power 1 value (length) of this expression if the expression can be so evaluated, or Integer.MIN_VALUE otherwise. The value is expressed in millipoints.

canEvalColor

public boolean canEvalColor()

Description copied from interface: PropertyValue

Indicates whether this property value has the ability to express itself as a Color.

Returns:

True iff this property value is a color.

evalColor

public Color evalColor()

Description copied from interface: PropertyValue

Return the color value of "this".

Returns:

The color representation of the value of "this".

lengthRequiresFontSize

public boolean lengthRequiresFontSize()

Description copied from interface: PropertyValue

Indicates whether the computation of the length will require an accurate font-size parameter.

Returns:

True iff the computation of the length will require an accurate font-size parameter.

canEvalInteger

public boolean canEvalInteger()

Description copied from interface: PropertyValue

Indicates whether this property value has the ability to express itself as an integer Numeric item.

Returns:

True iff this property value is an integer.

evalInteger

public int evalInteger()

Description copied from interface: PropertyValue

Return this value as an int. This method should only be executed on instances where PropertyValue.canEvalInteger() returns true. Doing so on other instances may result in an IllegalStateException.

Returns:

This value as an int.

canEvalKeyword

public boolean canEvalKeyword()

Description copied from interface: PropertyValue

Indicates whether this property value can evaluate to a keyword.

Returns:

True iff this property value can evaluate to a keyword.

evalKeyword

public PvKeyword evalKeyword()

Description copied from interface: PropertyValue

Returns the keyword value of this property value. This method should only be executed on instances where PropertyValue.canEvalKeyword() returns true. Doing so on other instances may result in an IllegalStateException.

Returns:

The keyword value of this property value.

canEvalPercentage

public boolean canEvalPercentage()

Description copied from interface: PropertyValue

Indicates whether this property value can evaluate to a percentage.

Returns:

True iff this property value can evaluate to a percentage.

evalPercentage

public float evalPercentage()

Description copied from interface: PropertyValue

Returns the percentage value of this property value. This method should only be executed on instances where PropertyValue.canEvalPercentage() returns true. Doing so on other instances may result in an IllegalStateException.

Returns:

The percentage value of this property value.