org.jrdf.graph
Class AbstractLiteral

java.lang.Object
  org.jrdf.graph.AbstractLiteral

All Implemented Interfaces:

Literal, Node, ObjectNode, Serializable, TypedNodeVisitable

Direct Known Subclasses:

LiteralImpl

public abstract class AbstractLiteral

extends Object

implements Literal, Serializable

A base implementation of an RDF Literal.

Version:

$Revision: 1.1 $

Author:

Andrew Newman, Simon Raboczi

See Also:

Serialized Form

Constructor Summary

protected	AbstractLiteral(String newLexicalForm) Construct a plain literal.
protected	AbstractLiteral(String newLexicalForm, String newLanguage) Construct a literal with language.
protected	AbstractLiteral(String newLexicalForm, URI newDatatypeURI) Construct a datatyped literal.

Method Summary

void	accept(TypedNodeVisitor visitor) Accept a call from a TypedNodeVisitor.
boolean	equals(Object obj) Indicates whether some other object is "equal to" this one.
URI	getDatatypeURI() Returns the URI of the RDF datatype of this resource, or null for a plain literal.
String	getEscapedForm() Provide a legible representation of a literal, following the N-Triples format defined in §3.2 of the W3C's RDF Test Cases Recommendation.
String	getEscapedLexicalForm() Returns an escaped lexical form where double quotes and backslashes are escaped.
String	getLanguage() Returns the language code of the literal.
String	getLexicalForm() Obtain the text of this literal.
int	hashCode() Returns a hash-code value for this literal.
boolean	isWellFormedXML() Whether the literal is well formed XML.
String	toString() Returns the lexical form.

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractLiteral

protected AbstractLiteral(String newLexicalForm)

Construct a plain literal.

Parameters:

newLexicalForm - the text part of the literal

Throws:

IllegalArgumentException - if newLexicalForm is null

AbstractLiteral

protected AbstractLiteral(String newLexicalForm,
                          String newLanguage)

Construct a literal with language.

Parameters:

newLexicalForm - the text part of the literal

newLanguage - the language code, possibly the empty string but not null

Throws:

IllegalArgumentException - if lexicalForm or lang are null

AbstractLiteral

protected AbstractLiteral(String newLexicalForm,
                          URI newDatatypeURI)

Construct a datatyped literal.

Parameters:

newLexicalForm - the text part of the literal

newDatatypeURI - the URI for a datatyped literal

Throws:

IllegalArgumentException - if lexicalForm or datatype are null

Method Detail

getLexicalForm

public String getLexicalForm()

Obtain the text of this literal.

Specified by:

getLexicalForm in interface Literal

Returns:

the text of the literal, never null

getLanguage

public String getLanguage()

Returns the language code of the literal. When no language is specified for a plain literal, this field contains a zero-length String. Otherwise, this will be null.

Specified by:

getLanguage in interface Literal

Returns:

the language code of the literal or null in the case of a datatyped literal.

isWellFormedXML

public boolean isWellFormedXML()

Whether the literal is well formed XML.

Specified by:

isWellFormedXML in interface Literal

Returns:

whether the literal is wll formed XML.

getDatatypeURI

public URI getDatatypeURI()

Returns the URI of the RDF datatype of this resource, or null for a plain literal.

Specified by:

getDatatypeURI in interface Literal

Returns:

the URI of the RDF datatype of this resource, or null for a plain literal.

accept

public void accept(TypedNodeVisitor visitor)

Accept a call from a TypedNodeVisitor.

Specified by:

accept in interface TypedNodeVisitable

Parameters:

visitor - the object doing the visiting.

equals

public boolean equals(Object obj)

Description copied from interface: Literal

Indicates whether some other object is "equal to" this one. A literal is equal to another literal if:

• The strings of the two lexical forms compare equal, character by character.
• Either both or neither have language tags.
• The language tags, if any, compare equal.
• Either both or neither have datatype URIs.
• The two datatype URIs, if any, compare equal, character by character.

Specified by:

equals in interface Literal

hashCode

public int hashCode()

Description copied from interface: Literal

Returns a hash-code value for this literal. The hash code is based upon XORing all of the literal's components hash codes including the lexical form, datatype, and language.

Specified by:

hashCode in interface Literal

getEscapedForm

public String getEscapedForm()

Provide a legible representation of a literal, following the N-Triples format defined in §3.2 of the W3C's RDF Test Cases Recommendation. Well-formed Unicode surrogate pairs in the lexical form are escaped as a single 8-digit hexadecimal \U escape sequence rather than a pair of 4-digit &x5C;u sequences representing the surrogates.

Specified by:

getEscapedForm in interface Literal

Returns:

this instance in N-Triples format

toString

public String toString()

Returns the lexical form.

Specified by:

toString in interface Literal

Returns:

the lexical form.

getEscapedLexicalForm

public String getEscapedLexicalForm()

Description copied from interface: Literal

Returns an escaped lexical form where double quotes and backslashes are escaped.

Specified by:

getEscapedLexicalForm in interface Literal

Returns:

String the lexical form.