org.protempa.proposition.value

Enum ValueComparator

java.lang.Object

java.lang.Enum<ValueComparator>

org.protempa.proposition.value.ValueComparator

All Implemented Interfaces:

Serializable, Comparable<ValueComparator>

public enum ValueComparator
extends Enum<ValueComparator>

Represents the possible valid comparisons between two Value objects. Some rules:

• Values are always NOT_EQUAL_TO null.
• Values are always NOT_EQUAL_TO a value of another type, except for the numeric types.
• Two null values are EQUAL_TO each other.
• A null value is NOT_EQUAL_TO any non-null value.

Author:

Andrew Post

Enum Constant Summary

Enum Constants

Enum Constant and Description
EQUAL_TO The two values are equal (=).
GREATER_THAN The first value is greater than (>) the second.
GREATER_THAN_OR_EQUAL_TO The first value is greater than or equal to (>=) the second.
IN The value is in the list.
LESS_THAN The first value is less than (<) the second.
LESS_THAN_OR_EQUAL_TO The first value is less than or equal to (<=) the second.
NOT_EQUAL_TO The two values are not equal (!=).
NOT_IN The value is not in the list.
UNKNOWN Unknown, meaning that Protempa cannot tell, for example, if a value may be less than another value but Protempa cannot tell with complete certainty.

Method Summary

Modifier and Type	Method and Description
boolean	compare(Value lhsValue, Value rhsValue) Returns whether two values have the relationship specified by this value comparator.
String	getComparatorString() Gets the string associated with this comparator object.
abstract boolean	includes(ValueComparator comparator) Returns whether this ValueComparator is the same as or includes the specified ValueComparator.
static ValueComparator	parse(String compString) Gets the comparison object corresponding to the given mathematical comparison symbol.
static ValueComparator	valueOf(String name) Returns the enum constant of this type with the specified name.
static ValueComparator[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

GREATER_THAN

public static final ValueComparator GREATER_THAN

The first value is greater than (>) the second.

LESS_THAN

public static final ValueComparator LESS_THAN

The first value is less than (<) the second.

EQUAL_TO

public static final ValueComparator EQUAL_TO

The two values are equal (=).

NOT_EQUAL_TO

public static final ValueComparator NOT_EQUAL_TO

The two values are not equal (!=).

UNKNOWN

public static final ValueComparator UNKNOWN

Unknown, meaning that Protempa cannot tell, for example, if a value may be less than another value but Protempa cannot tell with complete certainty.

GREATER_THAN_OR_EQUAL_TO

public static final ValueComparator GREATER_THAN_OR_EQUAL_TO

The first value is greater than or equal to (>=) the second. Includes EQUAL_TO and GREATER_THAN.

LESS_THAN_OR_EQUAL_TO

public static final ValueComparator LESS_THAN_OR_EQUAL_TO

The first value is less than or equal to (<=) the second. Includes EQUAL_TO and LESS_THAN.

IN

public static final ValueComparator IN

The value is in the list.

NOT_IN

public static final ValueComparator NOT_IN

The value is not in the list.

Method Detail

values

public static ValueComparator[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (ValueComparator c : ValueComparator.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static ValueComparator valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null

parse

public static ValueComparator parse(String compString)

Gets the comparison object corresponding to the given mathematical comparison symbol.

• "<" corresponds to LESS_THAN.
• ">" corresponds to GREATER_THAN.
• "<=" corresponds to LESS_THAN_OR_EQUAL_TO.
• ">=" corresponds to GREATER_THAN_OR_EQUAL_TO.
• "=" corresponds to EQUAL_TO.
• "!=" corresponds to NOT_EQUAL_TO.

Parameters:

compString - a String from the above list.

Returns:

a ValueComparator corresponding to the given comparison string, or null if one of the above strings was not passed in.

Throws:

ValueComparatorFormatException - if compString could not be parsed.

includes

public abstract boolean includes(ValueComparator comparator)

Returns whether this ValueComparator is the same as or includes the specified ValueComparator.

Parameters:

comparator - a ValueComparator.

Returns:

true if this ValueComparator is subsumed by the specified ValueComparator, false otherwise.

compare

public boolean compare(Value lhsValue,
                       Value rhsValue)

Returns whether two values have the relationship specified by this value comparator. It returns the same result as calling a value's Value.compare(org.protempa.proposition.value.Value) method, except it also handles gracefully the value being null.

Parameters:

lhsValue - the left-hand-side value. May be null.

rhsValue - the right-hand-side value. May be null.

Returns:

true if the two values have the relationship specified by this value comparator, false if not.

getComparatorString

public final String getComparatorString()

Gets the string associated with this comparator object.

Returns:

a String.