Class LiteralImpl

java.lang.Object

org.apache.commons.rdf.simple.LiteralImpl

All Implemented Interfaces:

Literal, RDFTerm, SimpleRDF.SimpleRDFTerm

final class LiteralImpl
extends Object
implements Literal, SimpleRDF.SimpleRDFTerm

A simple implementation of Literal.

Field Summary

Fields

Modifier and Type	Field	Description
private final IRI	dataType
private final String	languageTag
private final String	lexicalForm
private static final String	QUOTE

Constructor Summary

Constructors

Constructor	Description
LiteralImpl(String literal)
LiteralImpl(String literal, String languageTag)
LiteralImpl(String lexicalForm, IRI dataType)

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object obj)	Check it this Literal is equal to another Literal.
IRI	getDatatype()	The IRI identifying the datatype that determines how the lexical form maps to a literal value.
Optional<String>	getLanguageTag()	If and only if the datatype IRI is http://www.w3.org/1999/02/22-rdf-syntax-ns#langString, the language tag for this Literal is a non-empty language tag as defined by BCP47. If the datatype IRI is not http://www.w3.org/1999/02/22-rdf-syntax-ns#langString, this method must return Optional.empty().
String	getLexicalForm()	The lexical form of this literal, represented by a Unicode string.
int	hashCode()	Calculate a hash code for this Literal.
private static String	lowerCase(String langTag)
String	ntriplesString()	Return the term serialised as specified by the RDF-1.1 N-Triples Canonical form.
String	toString()

Methods inherited from class Object

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

Field Details

QUOTE

private static final String QUOTE

See Also:

• Constant Field Values

dataType

private final IRI dataType

languageTag

private final String languageTag

lexicalForm

private final String lexicalForm

Constructor Details

LiteralImpl

public LiteralImpl(String literal)

LiteralImpl

public LiteralImpl(String lexicalForm,
 IRI dataType)

LiteralImpl

public LiteralImpl(String literal,
 String languageTag)

Method Details

getDatatype

public IRI getDatatype()

Description copied from interface: Literal

The IRI identifying the datatype that determines how the lexical form maps to a literal value. If the datatype IRI is http://www.w3.org/1999/02/22-rdf-syntax-ns#langString, Literal.getLanguageTag() must not return Optional.empty(), and it must return a valid BCP47 language tag.

Specified by:

getDatatype in interface Literal

Returns:

The datatype IRI for this literal.

See Also:

• RDF-1.1 Literal datatype IRI

getLanguageTag

public Optional<String> getLanguageTag()

Description copied from interface: Literal

If and only if the datatype IRI is http://www.w3.org/1999/02/22-rdf-syntax-ns#langString, the language tag for this Literal is a non-empty language tag as defined by BCP47.
If the datatype IRI is not http://www.w3.org/1999/02/22-rdf-syntax-ns#langString, this method must return Optional.empty().

The value space of language tags is always in lower case; although RDF implementations MAY convert all language tags to lower case, safe comparisons of language tags should be done using String.toLowerCase(Locale) with the locale Locale.ROOT.

Implementation note: If your application requires Serializable objects, it is best not to store an Optional in a field. It is recommended to use Optional.ofNullable(Object) to create the return value for this method.

Specified by:

getLanguageTag in interface Literal

Returns:

The Optional language tag for this literal. If Optional.isPresent() returns true, the value returned by Optional.get() must be a non-empty language tag string conforming to BCP47.

See Also:

• RDF-1.1 Literal language tag

getLexicalForm

public String getLexicalForm()

Description copied from interface: Literal

The lexical form of this literal, represented by a Unicode string.

Specified by:

getLexicalForm in interface Literal

Returns:

The lexical form of this literal.

See Also:

• RDF-1.1 Literal lexical form

ntriplesString

public String ntriplesString()

Description copied from interface: RDFTerm

Return the term serialised as specified by the RDF-1.1 N-Triples Canonical form.

Specified by:

ntriplesString in interface RDFTerm

Returns:

The term serialised as RDF-1.1 N-Triples.

See Also:

• RDF-1.1 N-Triples Canonical form

toString

public String toString()

Overrides:

toString in class Object

hashCode

public int hashCode()

Description copied from interface: Literal

Calculate a hash code for this Literal.

The returned hash code MUST be equal to the result of Objects.hash(Object...) with the arguments Literal.getLexicalForm(), Literal.getDatatype(), Literal.getLanguageTag().map(s->s.toLowerString(Locale.ROOT)).

This method MUST be implemented in conjunction with Literal.equals(Object) so that two equal Literals produce the same hash code.

Specified by:

hashCode in interface Literal

Specified by:

hashCode in interface RDFTerm

Overrides:

hashCode in class Object

Returns:

a hash code value for this Literal.

See Also:

• Object.hashCode()
• Objects.hash(Object...)

lowerCase

private static String lowerCase(String langTag)

equals

public boolean equals(Object obj)

Description copied from interface: Literal

Check it this Literal is equal to another Literal.

Literal term equality: Two literals are term-equal (the same RDF literal) if and only if the two lexical forms, the two datatype IRIs, and the two language tags (if any) compare equal, character by character. Thus, two literals can have the same value without being the same RDF term.

As the value space for language tags is lower-space, if they are present, they MUST be compared character by character using the equivalent of String.toLowerCase(java.util.Locale) with the locale Locale.ROOT.

Implementations MUST also override Literal.hashCode() so that two equal Literals produce the same hash code.

Specified by:

equals in interface Literal

Specified by:

equals in interface RDFTerm

Overrides:

equals in class Object

Parameters:

obj - Another object

Returns:

true if other is a Literal and is equal to this

See Also:

• Object.equals(Object)