com.hp.util

Class Interval<D extends Comparable<D>>

java.lang.Object

com.hp.util.Interval<D>

Type Parameters:

D - Interval domain.

All Implemented Interfaces:

Serializable

public final class Interval<D extends Comparable<D>>
extends Object
implements Serializable

Intervals (of real numbers ) can be classified into different types. Let a and b be real numbers where with a < b:

• Empty: (a, a) = (a, a] = [a, a) = {} = empty. [b, a] is considered as an empty interval in the literature, but this class do not support it
• Degenerate: [a, a] = {a}
• Open: (a, b) = {x | a < x < b}
• Closed: [a, b] = {x | a <= x <= b}
• Left-closed, right-open: [a, b) = {x | a <= x < b}
• Left-open, right-closed: (a, b] = {x | a < x <= b}
• Left open right unbounded: (a, infinite) = {x | x > a}
• Left closed right unbounded: [a, infinite) = {x | x >= a}
• Left unbounded right open: (infinite, b) = {x | x < b}
• Left unbounded right closed: (infinite, b] = {x | x <= b}
• Unbounded: (infinite, infinite) = {x | x is a real number}

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Interval.Type

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Interval(D leftEndpoint, D rightEndpoint, Interval.Type type) Constructs an interval.

Method Summary

Modifier and Type	Method and Description
boolean	contains(D element) Verifies whether the given element belongs to the interval.
static <T extends Comparable<T>> Interval<T>	createClosed(T leftEndpoint, T rightEndpoint) Creates a closed-type interval based on the nullability of leftEndpoint and rightEndpoint: Closed: if neither leftEndpoint and rightEndpoint are null Left unbounded right closed: if leftEndpoint is null but rightEndpoint isn't Left closed right unbounded: if leftEndpoint is not null but rightEndpoint is Unbounded: if both leftEndpoint and rightEndpoint are null
static <T extends Comparable<T>> Interval<T>	createOpen(T leftEndpoint, T rightEndpoint) Creates an open-type interval based on the nullability of leftEndpoint and rightEndpoint: Open: if neither leftEndpoint and rightEndpoint are null Left unbounded right open: if leftEndpoint is null but rightEndpoint isn't Left open right unbounded: if leftEndpoint is not null but rightEndpoint is Unbounded: if both leftEndpoint and rightEndpoint are null
boolean	equals(Object obj)
D	getLeftEndpoint() Gets the interval left end point.
D	getRightEndpoint() Gets the interval right end point.
Interval.Type	getType() Gets the interval type.
int	hashCode()
boolean	isEmpty() Returns whether this interval is empty or not:
String	toString()
static <T extends Comparable<T>> Interval<T>	valueOfClosed(T leftEndpoint, T rightEndpoint) Creates a closed interval: [a, b] = {x | a <= x <= b}
static <T extends Comparable<T>> Interval<T>	valueOfLeftClosedRightOpen(T leftEndpoint, T rightEndpoint) Creates a left-closed right-open interval: (a, b] = {x | a < x <= b}
static <T extends Comparable<T>> Interval<T>	valueOfLeftClosedRightUnbounded(T leftEndpoint) Creates a Left closed right unbounded interval: [a, infinite) = {x | x >= a}
static <T extends Comparable<T>> Interval<T>	valueOfLeftOpenRightClosed(T leftEndpoint, T rightEndpoint) Creates a left-open right-closed interval: (a, b] = {x | a <= x < b}
static <T extends Comparable<T>> Interval<T>	valueOfLeftOpenRightUnbounded(T leftEndpoint) Creates a left open right unbounded interval: (a, infinite) = {x | x > a}
static <T extends Comparable<T>> Interval<T>	valueOfLeftUnboundedRightClosed(T rightEndpoint) Creates a left unbounded right closed interval: (infinite, b] = {x | x <= b}
static <T extends Comparable<T>> Interval<T>	valueOfLeftUnboundedRightOpen(T rightEndpoint) Creates a left unbounded right open interval: (infinite, b) = {x | x < b}
static <T extends Comparable<T>> Interval<T>	valueOfOpen(T leftEndpoint, T rightEndpoint) Creates a open interval: (a, b) = {x | a < x < b}
static <T extends Comparable<T>> Interval<T>	valueOfUnbounded() Creates an unbounded interval: (infinite, infinite) = {x | x is a real number}

Methods inherited from class java.lang.Object

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

Constructor Detail

Interval

protected Interval(D leftEndpoint,
                   D rightEndpoint,
                   Interval.Type type)
            throws NullPointerException,
                   IllegalArgumentException

Constructs an interval.

Parameters:

leftEndpoint - Left end point.

rightEndpoint - Right end point.

type - Interval type.

Throws:

NullPointerException - If interval type is null.

IllegalArgumentException - If interval validation fails based on the interval type.

Method Detail

valueOfOpen

public static <T extends Comparable<T>> Interval<T> valueOfOpen(T leftEndpoint,
                                                                T rightEndpoint)

Creates a open interval: (a, b) = {x | a < x < b}

Parameters:

leftEndpoint - Left end point.

rightEndpoint - Right end point.

Returns:

interval

valueOfClosed

public static <T extends Comparable<T>> Interval<T> valueOfClosed(T leftEndpoint,
                                                                  T rightEndpoint)

Creates a closed interval: [a, b] = {x | a <= x <= b}

Parameters:

leftEndpoint - Left end point.

rightEndpoint - Right end point.

Returns:

interval

valueOfLeftClosedRightOpen

public static <T extends Comparable<T>> Interval<T> valueOfLeftClosedRightOpen(T leftEndpoint,
                                                                               T rightEndpoint)

Creates a left-closed right-open interval: (a, b] = {x | a < x <= b}

Parameters:

leftEndpoint - Left end point.

rightEndpoint - Right end point.

Returns:

interval

valueOfLeftOpenRightClosed

public static <T extends Comparable<T>> Interval<T> valueOfLeftOpenRightClosed(T leftEndpoint,
                                                                               T rightEndpoint)

Creates a left-open right-closed interval: (a, b] = {x | a <= x < b}

Parameters:

leftEndpoint - Left end point.

rightEndpoint - Right end point.

Returns:

interval

valueOfLeftOpenRightUnbounded

public static <T extends Comparable<T>> Interval<T> valueOfLeftOpenRightUnbounded(T leftEndpoint)

Creates a left open right unbounded interval: (a, infinite) = {x | x > a}

Parameters:

leftEndpoint - Left end point.

Returns:

interval

valueOfLeftClosedRightUnbounded

public static <T extends Comparable<T>> Interval<T> valueOfLeftClosedRightUnbounded(T leftEndpoint)

Creates a Left closed right unbounded interval: [a, infinite) = {x | x >= a}

Parameters:

leftEndpoint - Left end point.

Returns:

interval

valueOfLeftUnboundedRightOpen

public static <T extends Comparable<T>> Interval<T> valueOfLeftUnboundedRightOpen(T rightEndpoint)

Creates a left unbounded right open interval: (infinite, b) = {x | x < b}

Parameters:

rightEndpoint - Right end point.

Returns:

interval

valueOfLeftUnboundedRightClosed

public static <T extends Comparable<T>> Interval<T> valueOfLeftUnboundedRightClosed(T rightEndpoint)

Creates a left unbounded right closed interval: (infinite, b] = {x | x <= b}

Parameters:

rightEndpoint - Right end point.

Returns:

interval

valueOfUnbounded

public static <T extends Comparable<T>> Interval<T> valueOfUnbounded()

Creates an unbounded interval: (infinite, infinite) = {x | x is a real number}

Returns:

interval

createOpen

public static <T extends Comparable<T>> Interval<T> createOpen(T leftEndpoint,
                                                               T rightEndpoint)
                                                        throws IllegalArgumentException

Creates an open-type interval based on the nullability of leftEndpoint and rightEndpoint:

• Open: if neither leftEndpoint and rightEndpoint are null
• Left unbounded right open: if leftEndpoint is null but rightEndpoint isn't
• Left open right unbounded: if leftEndpoint is not null but rightEndpoint is
• Unbounded: if both leftEndpoint and rightEndpoint are null

Parameters:

leftEndpoint - left endpoint

rightEndpoint - right endpoint

Returns:

one of the open-type intervals

Throws:

IllegalArgumentException - if neither leftEndpoint and rightEndpoint are null and leftEndpoint is be greater than rightEndpoint

createClosed

public static <T extends Comparable<T>> Interval<T> createClosed(T leftEndpoint,
                                                                 T rightEndpoint)
                                                          throws IllegalArgumentException

Creates a closed-type interval based on the nullability of leftEndpoint and rightEndpoint:

• Closed: if neither leftEndpoint and rightEndpoint are null
• Left unbounded right closed: if leftEndpoint is null but rightEndpoint isn't
• Left closed right unbounded: if leftEndpoint is not null but rightEndpoint is
• Unbounded: if both leftEndpoint and rightEndpoint are null

Parameters:

leftEndpoint - left endpoint

rightEndpoint - right endpoint

Returns:

one of the closed-type intervals

Throws:

IllegalArgumentException - if neither leftEndpoint and rightEndpoint are null and leftEndpoint is be greater than rightEndpoint

getLeftEndpoint

public D getLeftEndpoint()

Gets the interval left end point.

Returns:

the interval left end point or null

getRightEndpoint

public D getRightEndpoint()

Gets the interval right end point.

Returns:

the interval right end point or null

getType

public Interval.Type getType()

Gets the interval type.

Returns:

the interval type.

contains

public boolean contains(D element)

Verifies whether the given element belongs to the interval.

Parameters:

element - Element to verify.

Returns:

true if element belongs is inside the interval, false otherwise.

isEmpty

public boolean isEmpty()

Returns whether this interval is empty or not:

a, b are real numbers with a < b

empty: [b, a] = (a, a) = [a, a) = (a, a] = {}

Returns:

True if this interval is empty, false otherwise.

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object