Module org.apache.sis.util

Package org.apache.sis.measure

Class Range<E extends Comparable<? super E>>

Object

Range<E>

Type Parameters:

E - the type of range elements, typically a Number subclass or Date.

All Implemented Interfaces:

Serializable, Formattable, Checked­Container<E>, Emptiable

Direct Known Subclasses:

Number­Range

public class Range<E extends Comparable<? super E>>
extends Object
implements CheckedContainer<E>, Formattable, Emptiable, Serializable

A set of minimum and maximum values of a certain class, allowing a user to determine if a value of the same class is contained inside the range. The minimum and maximum values do not have to be included in the range, and can be null. If the minimum or maximum values are null, the range is said to be unbounded on that endpoint. If both the minimum and maximum are null, the range is completely unbounded and all values of that class are contained within the range. Null values are always considered exclusive, since iterations over the values will never reach the infinite endpoint.

The minimal and maximal values (the endpoints) may be inclusive or exclusive. Numeric ranges where both endpoints are inclusive are called closed intervals and are represented by square brackets, for example "[0 … 255]". Numeric ranges where both endpoints are exclusive are called open intervals and are represented by parenthesis, for example "(0 … 256)".

Type and value of range elements

To be a member of a Range, the <E> type defining the range must implement the Comparable interface. All argument values given to the methods of this class shall be or contain instances of that <E> type. The type is enforced by parameterized type, but some subclasses may put additional constraints. For example, Measurement­Range will additionally checks the units of measurement. Consequently, every methods defined in this class may throw an Illegal­Argument­Exception if a given argument does not met some constraint beyond the type.

Relationship with ISO 19123 definition of range

The ISO 19123 standard (Coverage geometry and functions) defines the range as the set (either finite or transfinite) of feature attribute values associated by a function (the coverage) with the elements of the coverage domain. In other words, if we see a coverage as a function, then a range is the set of possible return values.

The characteristics of the spatial domain are defined by the ISO 19123 standard whereas the characteristics of the attribute range are not part of that standard. In Apache SIS, those characteristics are described by the Sample­Dimension class, which may contain one or many Range instances. Consequently, this Range class is closely related, but not identical, to the ISO 19123 definition or range.

Ranges are not necessarily numeric. Numeric and non-numeric ranges can be associated to discrete coverages, while typically only numeric ranges can be associated to continuous coverages.

Immutability and thread safety

This class and the Number­Range / Measurement­Range subclasses are immutable, and thus inherently thread-safe. Other subclasses may or may not be immutable, at implementation choice. But implementers are encouraged to make sure that all subclasses remain immutable for more predictable behavior.

Since:

0.3

See Also:

• Range­Format
• Range­Set
• Serialized Form

Constructor Summary

Constructors

Constructor	Description
Range(Class<E> element­Type, E min­Value, boolean is­Min­Included, E max­Value, boolean is­Max­Included)	Creates a new range bounded by the given endpoint values.
Range(Range<E> range)	Constructs a range with the same type and the same values than the specified range.

Method Summary

Modifier and Type	Method	Description
boolean	contains(E value)	Returns true if this range contains the given value.
boolean	contains(Range<? extends E> range)	Returns true if the supplied range is fully contained within this range.
boolean	equals(Object object)	Compares this range with the given object for equality.
void	format­To(Formatter formatter, int flags, int width, int precision)	Formats this range using the provided formatter.
Class<E>	get­Element­Type()	Returns the base type of elements in this range.
E	get­Max­Value()	Returns the maximal value, or null if this range has no upper limit.
E	get­Min­Value()	Returns the minimal value, or null if this range has no lower limit.
int	hash­Code()	Returns a hash code value for this range.
Range<E>	intersect(Range<E> range)	Returns the intersection between this range and the given range.
boolean	intersects(Range<? extends E> range)	Returns true if this range intersects the given range.
boolean	is­Bounded()	Returns true if this range is both left-bounded and right-bounded.
final boolean	is­Empty()	Returns true if this range is empty.
boolean	is­Max­Included()	Returns true if the maximal value is inclusive, or false if exclusive.
boolean	is­Min­Included()	Returns true if the minimal value is inclusive, or false if exclusive.
Range<E>[]	subtract(Range<E> range)	Returns the range of values that are in this range but not in the given range.
String	to­String()	Returns a unlocalized string representation of this range.
Range<E>	union(Range<E> range)	Returns the union of this range with the given range.

Methods inherited from class Object

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

Constructor Details

Range

public Range(Range<E> range)

Constructs a range with the same type and the same values than the specified range. This is a copy constructor.

Parameters:

range - the range to copy.

Range

public Range(Class<E> elementType,
 E minValue,
 boolean isMinIncluded,
 E maxValue,
 boolean isMaxIncluded)

Creates a new range bounded by the given endpoint values. If the given minimum value is greater than the maximum value, then the range is empty.

Assertion

This constructor verifies the min­Value and max­Value arguments type if Java assertions are enabled. This verification is not performed in normal execution because theoretically unnecessary unless Java generic types have been tricked.

Parameters:

element­Type - the base type of the range elements.

min­Value - the minimal value, or null if none.

is­Min­Included - true if the minimal value is inclusive, or false if exclusive.

max­Value - the maximal value, or null if none.

is­Max­Included - true if the maximal value is inclusive, or false if exclusive.

Throws:

Assertion­Error - if assertions are enabled and the given values are not compatible with the given type.

Method Details

getElementType

public Class<E> getElementType()

Returns the base type of elements in this range. This is the type specified at construction time.

Specified by:

get­Element­Type in interface Checked­Container<E extends Comparable<? super E>>

Returns:

the element type.

getMinValue

public E getMinValue()

Returns the minimal value, or null if this range has no lower limit. If non-null, the returned value is either inclusive or exclusive depending on the boolean returned by is­Min­Included().

Returns:

the minimal value, or null if this range is unbounded on the lower side.

isMinIncluded

public boolean isMinIncluded()

Returns true if the minimal value is inclusive, or false if exclusive. Note that null values are always considered exclusive.

Returns:

true if the minimal value is inclusive, or false if exclusive.

getMaxValue

public E getMaxValue()

Returns the maximal value, or null if this range has no upper limit. If non-null, the returned value is either inclusive or exclusive depending on the boolean returned by is­Max­Included().

Returns:

the maximal value, or null if this range is unbounded on the upper side.

isMaxIncluded

public boolean isMaxIncluded()

Returns true if the maximal value is inclusive, or false if exclusive. Note that null values are always considered exclusive.

Returns:

true if the maximal value is inclusive, or false if exclusive.

isEmpty

public final boolean isEmpty()

Returns true if this range is empty. A range is empty if the minimum value is greater than the maximum value, or if they are equal while at least one of them is exclusive, or if both bounds are NaN.

API note

This method is final because often used by the internal implementation. Making the method final ensures that the other methods behave consistently.

Specified by:

is­Empty in interface Emptiable

Returns:

true if this range is empty.

isBounded

public boolean isBounded()

Returns true if this range is both left-bounded and right-bounded. A true return value guarantees that:

1. both get­Min­Value() and get­Max­Value() will return non-null values;
2. if minimum and maximum values are numbers, then those numbers are finite.

Returns:

whether this range is left- and right-bounded.

Since:

1.0

contains

public boolean contains(E value)

Returns true if this range contains the given value. A range never contains the null value. This is consistent with the class javadoc stating that null minimum or maximum values are exclusive.

Parameters:

value - the value to check for inclusion in this range.

Returns:

true if the given value is included in this range.

contains

public boolean contains(Range<? extends E> range)

Returns true if the supplied range is fully contained within this range.

Parameters:

range - the range to check for inclusion in this range.

Returns:

true if the given range is included in this range.

Throws:

Illegal­Argument­Exception - if the given range is incompatible, for example because of incommensurable units of measurement.

intersects

public boolean intersects(Range<? extends E> range)

Returns true if this range intersects the given range.

Parameters:

range - the range to check for intersection with this range.

Returns:

true if the given range intersects this range.

Throws:

Illegal­Argument­Exception - if the given range is incompatible, for example because of incommensurable units of measurement.

intersect

public Range<E> intersect(Range<E> range)

Returns the intersection between this range and the given range.

Parameters:

range - the range to intersect.

Returns:

the intersection of this range with the given range.

Throws:

Illegal­Argument­Exception - if the given range is incompatible, for example because of incommensurable units of measurement.

union

public Range<E> union(Range<E> range)

Returns the union of this range with the given range.

Parameters:

range - the range to add to this range.

Returns:

the union of this range with the given range.

Throws:

Illegal­Argument­Exception - if the given range is incompatible, for example because of incommensurable units of measurement.

subtract

public Range<E>[] subtract(Range<E> range)

Returns the range of values that are in this range but not in the given range. This method returns an array of length 0, 1 or 2:

• If the given range contains fully this range, returns an array of length 0.
• If the given range is in the middle of this range, then the subtraction results in two disjoint ranges which will be returned as two elements in the array.
• Otherwise returns an array of length 1.

Parameters:

range - the range to subtract.

Returns:

this range without the given range, as an array of length 0, 1 or 2.

Throws:

Illegal­Argument­Exception - if the given range is incompatible, for example because of incommensurable units of measurement.

equals

public boolean equals(Object object)

Compares this range with the given object for equality. Two ranges are considered equal if they met the following conditions:

• They are of the same class.
• They have the same element type.
• Both ranges are empty, or (if at least one range is non-empty):
  • They have equal minimum value in the sense of Object.equals(Object).
  • They have equal maximum value in the sense of Object.equals(Object).
  • They have equal inclusive minimum flag.
  • They have equal inclusive maximum flag.
• Any other requirement added by subclasses. In particular Measurement­Range compares also the units of measurement.

Note that this method may return true even if the bounds are not strictly identical. In particular this method returns true if the ranges are empty regardless their minimum and maximum values, and also returns true if the bounds are wrappers for some Float.Na­N or Double.Na­N values even if their raw bits pattern are not the same. The latter is because Float.equals(Object) and Double.equals(Object) consider all NaN values as equal.

Overrides:

equals in class Object

Parameters:

object - the object to compare with this range for equality.

Returns:

true if the given object is equal to this range.

hashCode

public int hashCode()

Returns a hash code value for this range.

Overrides:

hash­Code in class Object

toString

public String toString()

Returns a unlocalized string representation of this range. This method complies to the format described in the ISO 31-11 standard, except that the minimal and maximal values are separated by the "…" character instead of coma. More specifically, the string representation is defined as below:

• If the range is empty, then this method returns "{}".
• Otherwise if the minimal value is equal to the maximal value, then the string representation of that value is returned inside braces as in "{value}".
• Otherwise the string representation of the minimal and maximal values are formatted like "[min … max]" for inclusive endpoints or "(min … max)" for exclusive endpoints, or a mix of both styles. The "∞" symbol is used in place of min or max for unbounded ranges.

If this range is a Measurement­Range, then the unit of measurement is appended to the above string representation except for empty ranges.

Overrides:

to­String in class Object

See Also:

• Range­Format
• Wikipedia: ISO 31-11

formatTo

public void formatTo(Formatter formatter,
 int flags,
 int width,
 int precision)

Formats this range using the provided formatter. This method is invoked when a Range object is formatted using the "%s" conversion specifier of Formatter. Users don't need to invoke this method explicitly.

If the alternate flags is present (as in "%#s"), then the range will be formatted using the alternate form for exclusive bounds.

Specified by:

format­To in interface Formattable

Parameters:

formatter - the formatter in which to format this range.

flags - Formattable­Flags.LEFT_JUSTIFY for left alignment, or 0 for right alignment.

width - minimal number of characters to write, padding with ' ' if necessary.

precision - maximal number of characters to write, or -1 if no limit.