/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.jena.datatypes.xsd.impl;
import java.io.IOException ;
import java.io.StringReader ;
import org.apache.jena.datatypes.BaseDatatype ;
import org.apache.jena.datatypes.DatatypeFormatException ;
import org.apache.jena.datatypes.RDFDatatype ;
import org.apache.jena.rdfxml.xmlinput.ALiteral ;
import org.apache.jena.rdfxml.xmlinput.ARP ;
import org.apache.jena.rdfxml.xmlinput.AResource ;
import org.apache.jena.rdfxml.xmlinput.StatementHandler ;
import org.apache.jena.shared.BrokenException ;
import org.xml.sax.ErrorHandler ;
import org.xml.sax.SAXException ;
import org.xml.sax.SAXParseException ;
/**
* Builtin data type to represent XMLLiteral (i.e. items created
* by use of <code>rdf:parsetype='literal'</code>.
*/
public class XMLLiteralType extends BaseDatatype implements RDFDatatype {
/** Singleton instance */
// Include the string for the RDF namespace, not use RDF.getURI(), to avoid an initializer circularity
public static final RDFDatatype theXMLLiteralType = new XMLLiteralType("http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral");
/**
* Private constructor.
*/
private XMLLiteralType(String uri) {
super(uri);
}
/**
* Convert a serialize a value of this datatype out
* to lexical form.
*/
@Override
public String unparse(Object value) {
return value.toString();
}
/**
* Parse a lexical form of this datatype to a value
* @throws DatatypeFormatException if the lexical form is not legal
*/
@Override
public Object parse(String lexicalForm) throws DatatypeFormatException {
if ( !isValid(lexicalForm))
throw new DatatypeFormatException("Bad rdf:XMLLiteral");
return lexicalForm;
}
/**
* Test whether the given string is a legal lexical form
* of this datatype.
*/
@Override
public boolean isValid(final String lexicalForm) {
/*
* To check the lexical form we construct
* a dummy RDF/XML document and parse it with
* ARP. ARP performs an exclusive canonicalization,
* the dummy document has exactly one triple.
* If the lexicalForm is valid then the resulting
* literal found by ARP is unchanged.
* All other scenarios are either impossible
* or occur because the lexical form is invalid.
*/
final boolean status[] = new boolean[]{false,false,false};
// status[0] true on error or other reason to know that this is not well-formed
// status[1] true once first triple found
// status[2] the result (good if status[1] and not status[0]).
ARP arp = new ARP();
arp.getHandlers().setErrorHandler(new ErrorHandler(){
@Override
public void fatalError(SAXParseException e){
status[0] = true;
}
@Override
public void error(SAXParseException e){
status[0] = true;
}
@Override
public void warning(SAXParseException e){
status[0] = true;
}
});
arp.getHandlers().setStatementHandler(new StatementHandler(){
@Override
public void statement(AResource a, AResource b, ALiteral l){
/* this method is invoked exactly once
* while parsing the dummy document.
* The l argument is in exclusive canonical XML and
* corresponds to where the lexical form has been
* in the dummy document. The lexical form is valid
* iff it is unchanged.
*/
if (status[1] || !l.isWellFormedXML()) {
status[0] = true;
}
//throw new BrokenException("plain literal in XMLLiteral code.");
status[1] = true;
status[2] = l.toString().equals(lexicalForm);
}
@Override
public void statement(AResource a, AResource b, AResource l){
status[0] = true;
//throw new BrokenException("resource valued RDF/XML in XMLLiteral code.");
}
});
try {
arp.load(new StringReader(
"<rdf:RDF xmlns:rdf='http://www.w3.org/1999/02/22-rdf-syntax-ns#'>\n"
+"<rdf:Description><rdf:value rdf:parseType='Literal'>"
+lexicalForm+"</rdf:value>\n"
+"</rdf:Description></rdf:RDF>"
));
}
catch (IOException ioe){
throw new BrokenException(ioe);
}
catch (SAXException s){
return false;
}
return (!status[0])&&status[1]&&status[2];
}
}