Package org.nineml.coffeegrinder.tokens

Class TokenUndefined

java.lang.Object

org.nineml.coffeegrinder.util.Decoratable

org.nineml.coffeegrinder.tokens.Token

org.nineml.coffeegrinder.tokens.TokenUndefined

public class TokenUndefined
extends Token

A token that can match nothing.

This is used to provide a "right hand side" for undefined tokens. They can't match anything.

Field Summary

Fields

Modifier and Type	Field	Description
static TokenUndefined	undefined	The undefined token.

Method Summary

Modifier and Type	Method	Description
boolean	equals(java.lang.Object obj)	Test tokens for equality.
void	export(GrammarExporter exporter)	Export the token using the specified exporter.
java.lang.String	getValue()	Return the string value of this token.
int	hashCode()	Assure that equal tokens return the same hash code.
boolean	matches(Token input)	Does this token match the input?
java.lang.String	toString()	Pretty print a token.

Methods inherited from class org.nineml.coffeegrinder.util.Decoratable

addAttribute, addAttributes, getAttribute, getAttributes, getAttributesMap, getAttributeValue, hasAttribute

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Field Detail

undefined

public static final TokenUndefined undefined

The undefined token.

Method Detail

getValue

public java.lang.String getValue()

Return the string value of this token.

Specified by:

getValue in class Token

Returns:

The string value of the token ("<undefined>").

matches

public boolean matches(Token input)

Does this token match the input?

No, it does not.

Specified by:

matches in class Token

Parameters:

input - The input.

Returns:

true if they match.

export

public void export(GrammarExporter exporter)

Description copied from class: Token

Export the token using the specified exporter.

Specified by:

export in class Token

Parameters:

exporter - the exporter.

equals

public boolean equals(java.lang.Object obj)

Test tokens for equality.

The singleton TokenUndefined is only equal to itself.

Overrides:

equals in class java.lang.Object

Parameters:

obj - An object.

Returns:

true if obj is equal to this terminal character.

hashCode

public int hashCode()

Assure that equal tokens return the same hash code.

Overrides:

hashCode in class java.lang.Object

Returns:

the hash code.

toString

public java.lang.String toString()

Pretty print a token.

Overrides:

toString in class java.lang.Object

Returns:

a string representation of the object.