facets.util
Class NumberPolicy

java.lang.Object
  facets.util.Tracer
      facets.util.NumberPolicy

Direct Known Subclasses:

NumberPolicy.Ticked

public class NumberPolicy
extends Tracer

Validation and display of numbers.

NumberPolicy supplies the policy information required when validating a number or displaying it in the application surface.

Nested Class Summary

static class	NumberPolicy.Ticked Validation and tick-based display of numbers.
static class	NumberPolicy.ValueVariable NumberPolicy.Ticked that adjusts to changes in the value managed.

Field Summary

static int	COLUMNS_DEFAULT
static boolean	debug
static int	FORMAT_DECIMALS_0
static int	FORMAT_DECIMALS_1
static int	FORMAT_DECIMALS_2
static int	FORMAT_DECIMALS_3
static int	FORMAT_DECIMALS_4
static int	FORMAT_HEX
static double	MAX_VALUE
static double	MIN_VALUE
static double	UNIT_JUMP_DEFAULT

Constructor Summary

NumberPolicy(double min, double max)
Construct a policy that constrains valid values within the immutable range min to max.

Method Summary

boolean	canCycle() If true, values outside the range will be normalised to within it.
int	columns() The column width for text boxes in which values are to be displayed.
protected boolean	debug()
int	format() Hint on formatting the number.
java.lang.String[]	incrementTitles() Human-readable description of increment directions.
double	max() The highest possible value under the policy.
double	min() The lowest possible value under the policy.
protected boolean	reverseIncrements() Reverses the normal increment direction.
java.lang.String	toString()
double	unit() The smallest possible increment under the policy.
protected double	unitJump() Returns the multiple of unit defining the current minimum valid value change.
double	validIncrement(double existing, boolean positive) Returns a valid increment to existing in the direction given by positive, or zero if the incremented value is outside the range.
double	validValue(double existing, double proposed) Returns the nearest valid value to proposed.

Methods inherited from class facets.util.Tracer

trace, trace, trace, trace, trace, traceDebug, traceDebug, traceObjectText, traceOutput, traceOutputWithClass

Methods inherited from class java.lang.Object

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

Field Detail

MIN_VALUE

public static final double MIN_VALUE

See Also:

Constant Field Values

MAX_VALUE

public static final double MAX_VALUE

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Constant Field Values

debug

public static final boolean debug

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Constant Field Values

UNIT_JUMP_DEFAULT

public static double UNIT_JUMP_DEFAULT

COLUMNS_DEFAULT

public static int COLUMNS_DEFAULT

FORMAT_DECIMALS_0

public static final int FORMAT_DECIMALS_0

See Also:

Constant Field Values

FORMAT_DECIMALS_1

public static final int FORMAT_DECIMALS_1

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Constant Field Values

FORMAT_DECIMALS_2

public static final int FORMAT_DECIMALS_2

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Constant Field Values

FORMAT_DECIMALS_3

public static final int FORMAT_DECIMALS_3

See Also:

Constant Field Values

FORMAT_DECIMALS_4

public static final int FORMAT_DECIMALS_4

See Also:

Constant Field Values

FORMAT_HEX

public static final int FORMAT_HEX

See Also:

Constant Field Values

Constructor Detail

NumberPolicy

public NumberPolicy(double min,
                    double max)

Construct a policy that constrains valid values within the immutable range min to max.

Method Detail

max

public double max()

The highest possible value under the policy.

Set immutably during construction but only accessed via this method, enabling subclasses to define it dynamically by overriding.

min

public double min()

The lowest possible value under the policy.

Set immutably during construction but only accessed via this method, enabling subclasses to define it dynamically by overriding.

validIncrement

public final double validIncrement(double existing,
                                   boolean positive)

Returns a valid increment to existing in the direction given by positive, or zero if the incremented value is outside the range.

Calculation of the increment takes into account unit, unitJump, and reverseIncrements and its sum with existing is validated using valueValue.

validValue

public double validValue(double existing,
                         double proposed)

Returns the nearest valid value to proposed.

Though not used in the basic implementation, specifying existing as a parameter allows for non-linear validation in subclasses.

debug

protected boolean debug()

unit

public double unit()

The smallest possible increment under the policy.

The default implementation deduces this value from format().

canCycle

public boolean canCycle()

If true, values outside the range will be normalised to within it.

Default is false.

format

public int format()

Hint on formatting the number.

These are defined by the class FORMAT_x constants, which are mutually exclusive.

For FORMAT_PLACES_x constants the format should normally be consistent with unit.

columns

public int columns()

The column width for text boxes in which values are to be displayed.

Follows AWT convention.

incrementTitles

public java.lang.String[] incrementTitles()

Human-readable description of increment directions.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

reverseIncrements

protected boolean reverseIncrements()

Reverses the normal increment direction.

Used by validIncrement, default is false.

unitJump

protected double unitJump()

Returns the multiple of unit defining the current minimum valid value change.