/*
* $Header$
* $Revision: 624 $
* $Date: 2006-06-24 21:02:12 +1000 (Sat, 24 Jun 2006) $
*
* ====================================================================
*
* The Apache Software License, Version 1.1
*
* Copyright (c) 2003, 2004 The JRDF Project. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowlegement:
* "This product includes software developed by the
* the JRDF Project (http://jrdf.sf.net/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "The JRDF Project" and "JRDF" must not be used to endorse
* or promote products derived from this software without prior written
* permission. For written permission, please contact
* newmana@users.sourceforge.net.
*
* 5. Products derived from this software may not be called "JRDF"
* nor may "JRDF" appear in their names without prior written
* permission of the JRDF Project.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the JRDF Project. For more
* information on JRDF, please see <http://jrdf.sourceforge.net/>.
*/
package org.jrdf.graph;
// Java 2 standard
import org.jrdf.util.EscapeUtil;
import org.openrdf.model.impl.LiteralImpl;
import org.openrdf.model.impl.URIImpl;
import static org.mulgara.util.ObjectUtil.eq;
import java.io.Serializable;
import java.net.URI;
/**
* A base implementation of an RDF {@link Literal}.
*
* @author Andrew Newman
* @author Simon Raboczi
*
* @version $Revision: 624 $
*/
public abstract class AbstractLiteral extends LiteralImpl implements Literal, Serializable {
/**
* Allow newer compiled version of the stub to operate when changes
* have not occurred with the class.
* NOTE : update this serialVersionUID when a method or a public member is
* deleted.
*/
private static final long serialVersionUID = 1191947630907453592L;
/**
* Whether the literal is well formed XML.
*/
private boolean wellFormedXML;
/**
* RDF datatype URI, <code>null</code> for untyped literal.
*/
private URI datatypeURI;
/**
* Construct a plain literal.
*
* @param newLexicalForm the text part of the literal
* @throws IllegalArgumentException if <var>newLexicalForm</var> is <code>null</code>
*/
protected AbstractLiteral(String newLexicalForm) {
super(newLexicalForm);
// Validate "newLexicalForm" parameter
if (null == newLexicalForm) {
throw new IllegalArgumentException("Null \"newLexicalForm\" parameter");
}
// Initialize fields
datatypeURI = null;
}
/**
* Construct a literal with language.
*
* @param newLexicalForm the text part of the literal
* @param newLanguage the language code, possibly the empty string but not
* <code>null</code>
* @throws IllegalArgumentException if <var>lexicalForm</var> or
* <var>lang</var> are <code>null</code>
*/
protected AbstractLiteral(String newLexicalForm, String newLanguage) {
super(newLexicalForm, "".equals(newLanguage) ? null : newLanguage);
// Validate "lexicalForm" parameter
if (null == newLexicalForm) {
throw new IllegalArgumentException("Null \"lexicalForm\" parameter");
}
// Validate "language" parameter
if (null == newLanguage) {
throw new IllegalArgumentException("Null \"language\" parameter");
}
// Initialize fields
datatypeURI = null;
}
/**
* Construct a datatyped literal.
*
* @param newLexicalForm the text part of the literal
* @param newDatatypeURI the URI for a datatyped literal
* @throws IllegalArgumentException if <var>lexicalForm</var> or
* <var>datatype</var> are <code>null</code>
*/
protected AbstractLiteral(String newLexicalForm, URI newDatatypeURI) {
super(newLexicalForm, newDatatypeURI != null ? new URIImpl(newDatatypeURI.toString()) : null);
// Validate "lexicalForm" parameter
if (null == newLexicalForm) {
throw new IllegalArgumentException("Null \"lexicalForm\" parameter");
}
// Validate "datatype" parameter
if (null == newDatatypeURI) {
throw new IllegalArgumentException("Null \"datatype\" parameter");
}
// Initialize fields
datatypeURI = newDatatypeURI;
}
/**
* Obtain the text of this literal.
*
* @return the text of the literal, never <code>null</code>
*/
public String getLexicalForm() {
return getLabel();
}
/**
* Whether the literal is well formed XML.
*
* @return whether the literal is wll formed XML.
*/
public boolean isWellFormedXML() {
return wellFormedXML;
}
/**
* Returns the URI of the RDF datatype of this resource, or <code>null</code>
* for a plain literal.
*
* @return the URI of the RDF datatype of this resource, or <code>null</code>
* for a plain literal.
*/
public URI getDatatypeURI() {
return datatypeURI;
}
/**
* Accept a call from a TypedNodeVisitor.
*
* @param visitor the object doing the visiting.
*/
public void accept(TypedNodeVisitor visitor) {
visitor.visitLiteral(this);
}
/**
* Provide a legible representation of a literal, following the N-Triples
* format defined in
* <a href="http://www.w3.org/TR/2004/REC-rdf-testcases-20040210/#ntrip_strings">§3.2</a>
* of the <a href="http://www.w3.org/">W3C</a>'s (World Wide Web Consortium)
* <a href="http://www.w3.org/TR/2004/REC-rdf-testcases-20040210">RDF Test Cases</a> Recommendation.
*
* Well-formed Unicode surrogate pairs in the lexical form are escaped as a
* single 8-digit hexadecimal <code>\U</code> escape sequence rather than a
* pair of 4-digit <code>&x5C;u</code> sequences representing the surrogates.
*
* @return this instance in N-Triples format
*/
public String getEscapedForm() {
String escaped = EscapeUtil.escapeUTF8(getLexicalForm());
return '\"' + escaped + '\"' + appendType();
}
/**
* Returns the lexical form.
*
* @return the lexical form.
*/
public String toString() {
return '\"' + getEscapedLexicalForm() + '\"' + appendType();
}
public String getEscapedLexicalForm() {
return getLexicalForm().replaceAll("\\\\", "\\\\\\\\").replaceAll("\\\"",
"\\\\\\\"");
}
/**
* Appends the datatype URI or language code of a literal.
*
* @return String the datatype URI in the form ^^<->, or language code @- or
* an empty string.
*/
private String appendType() {
String appendString = "";
if (null != getDatatypeURI()) {
appendString = "^^<" + getDatatypeURI() + '>';
}
else if (getLanguage() != null) {
appendString = '@' + getLanguage();
}
return appendString;
}
public boolean equals(Object o) {
if (!(o instanceof Literal)) return false;
Literal l = (Literal)o;
return eq(getLexicalForm(), l.getLexicalForm()) &&
eq(getDatatypeURI(), l.getDatatypeURI()) &&
eq(getLanguage(), l.getLanguage());
}
public int hashCode() {
return super.hashCode();
}
public boolean isLiteral() { return true; }
public boolean isBlankNode() { return false; }
public boolean isURIReference() { return false; }
}