com.programix.util
Class TriState

java.lang.Object
  com.programix.util.TriState

All Implemented Interfaces:

Serializable, Comparable

public final class TriState
extends Object
implements Serializable, Comparable

Holds one of three states: YES, NO, and UNKNOWN. This can be used instead of a boolean to hold a third state of "don't know" or "unknown". This can also be used instead of a Boolean reference so that "unknown" can be explicitly represented as opposed to using a null reference to implicitly indicate "unknown".

Author:

Paul Hyde

See Also:

Serialized Form

Field Summary

static TriState	NO Indicates that the state is known and that it is "no" (or "false", or "off", or "negative").
static TriState	UNKNOWN Indicates that the state is unknown (neither "yes" or "no" is known at this point).
static List	VALUE_LIST An unmodifiable List of all the instances of TriState.
static TriState	YES Indicates that the state is known and that it is "yes" (or "true", or "on", or "affirmative").

Method Summary

int	compareTo(Object obj)
boolean	equals(Object obj)
String	getName() Returns the name of this instance, one of: "YES", "NO", or "UNKNOWN".
static TriState[]	getValues() Returns an array of all the instances of TriState.
int	hashCode()
boolean	isKnown() Returns true if the state is either YES or NO (not UNKNOWN).
boolean	isNo() Returns true if the state is NO.
boolean	isNotNo() Returns true if the state is not NO, but is either YES or UNKNOWN.
boolean	isNotYes() Returns true if the state is not YES, but is either NO or UNKNOWN.
boolean	isUnknown() Returns true if the state is neither YES nor NO, but is UNKNOWN.
boolean	isYes() Returns true if the state is YES.
String	toString()
static TriState	valueOf(String name) Returns the instance whose getName() method returns a String that matches the name passed in.

Methods inherited from class java.lang.Object

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

Field Detail

YES

public static final TriState YES

Indicates that the state is known and that it is "yes" (or "true", or "on", or "affirmative").

See Also:

NO, UNKNOWN

NO

public static final TriState NO

Indicates that the state is known and that it is "no" (or "false", or "off", or "negative").

See Also:

YES, UNKNOWN

UNKNOWN

public static final TriState UNKNOWN

Indicates that the state is unknown (neither "yes" or "no" is known at this point).

See Also:

YES, NO

VALUE_LIST

public static final List VALUE_LIST

An unmodifiable List of all the instances of TriState.

Method Detail

getValues

public static TriState[] getValues()

Returns an array of all the instances of TriState. A cloned copy is returned, so no special care is required.

valueOf

public static TriState valueOf(String name)
                        throws IllegalArgumentException

Returns the instance whose getName() method returns a String that matches the name passed in. The matching is done ignoring any case differences and after trimming any leading or trailing whitespace on the string passed in.

Parameters:

name - the name to search for.

Returns:

the matching instance

Throws:

IllegalArgumentException - if no match is found.

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

compareTo

public int compareTo(Object obj)

Specified by:

compareTo in interface Comparable

getName

public String getName()

Returns the name of this instance, one of: "YES", "NO", or "UNKNOWN".

isKnown

public boolean isKnown()

Returns true if the state is either YES or NO (not UNKNOWN).

isUnknown

public boolean isUnknown()

Returns true if the state is neither YES nor NO, but is UNKNOWN.

isYes

public boolean isYes()

Returns true if the state is YES.

isNotYes

public boolean isNotYes()

Returns true if the state is not YES, but is either NO or UNKNOWN.

isNo

public boolean isNo()

Returns true if the state is NO.

isNotNo

public boolean isNotNo()

Returns true if the state is not NO, but is either YES or UNKNOWN.