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ARQ is a SPARQL 1.1 query engine for Apache Jena
/*
* 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.riot.writer;
import java.io.OutputStream ;
import java.util.Objects ;
import org.apache.jena.atlas.io.IndentedWriter ;
import org.apache.jena.datatypes.xsd.impl.XMLLiteralType ;
import org.apache.jena.graph.Node ;
import org.apache.jena.graph.Triple ;
import org.apache.jena.rdf.model.impl.Util ;
import org.apache.jena.riot.RiotException ;
import org.apache.jena.riot.lang.ReaderTriX ;
import org.apache.jena.riot.lang.TriX ;
import org.apache.jena.riot.system.PrefixMap ;
import org.apache.jena.riot.system.PrefixMapFactory ;
import org.apache.jena.riot.system.StreamRDF ;
import org.apache.jena.sparql.core.Quad ;
/** Write TriX by streaming.
* See {@link TriX} for details.
*
* @see TriX
* @see ReaderTriX
* @see WriterTriX
*/
public class StreamWriterTriX implements StreamRDF {
/*
* Notes on writing qname:
* 1/ Currently disabled in favour of the most regular XML output.
* 2/ There is code in write(...,Node,...) to handle it currently commented out.
* 3/ Need to write prefixes which in turn needs delaying writing the start.
*/
private static String rdfXMLLiteral = XMLLiteralType.theXMLLiteralType.getURI() ;
private IndentedWriter out ;
private Node gn = null ;
private boolean inGraph = false ;
private PrefixMap pmap = PrefixMapFactory.create() ;
private int depth = 0 ; // Start/finish count
public StreamWriterTriX(OutputStream out) { this.out = new IndentedWriter(out) ; }
public StreamWriterTriX(IndentedWriter out) { this.out = out ; }
@Override public void start() {
if ( depth == 0 ) {
StreamWriterTriX.startXML(out) ;
// Wirte using the element name from the W3C DTD.
StreamWriterTriX.startTag(out, TriX.tagTriX, "xmlns", TriX.NS) ;
out.println() ;
}
depth ++ ;
}
@Override public void finish() {
depth-- ;
if ( depth != 0 )
return ;
if ( inGraph ) {
StreamWriterTriX.endTag(out, TriX.tagGraph) ;
out.println() ;
}
StreamWriterTriX.endTag(out, TriX.tagTriX) ;
out.println() ;
out.flush() ;
}
@Override public void base(String base) {} // Ignore.
@Override public void prefix(String prefix, String iri) {
pmap.add(prefix, iri) ;
}
@Override
public void triple(Triple triple) {
if ( inGraph && gn != null ) {
StreamWriterTriX.endTag(out, TriX.tagGraph) ;
out.println() ;
inGraph = false ;
}
if ( ! inGraph ) {
StreamWriterTriX.startTag(out, TriX.tagGraph) ;
out.println() ;
}
inGraph = true ;
gn = null ;
//end graph?
StreamWriterTriX.write(out, triple, pmap) ;
}
@Override
public void quad(Quad quad) {
Node g = quad.getGraph() ;
if ( g == null || Quad.isDefaultGraph(g) ) {
triple(quad.asTriple()) ;
return ;
}
if ( inGraph ) {
if ( ! Objects.equals(g, gn) ) {
StreamWriterTriX.endTag(out, TriX.tagGraph) ;
out.println() ;
inGraph = false ;
}
}
if ( ! inGraph ) {
StreamWriterTriX.startTag(out, TriX.tagGraph) ;
out.println() ;
if ( gn == null || ! Quad.isDefaultGraph(gn) ) {
gn = quad.getGraph() ;
StreamWriterTriX.write(out, gn, pmap) ;
}
}
inGraph = true ;
gn = g ;
StreamWriterTriX.write(out, quad.asTriple(), pmap) ;
}
static void write(IndentedWriter out, Triple triple, PrefixMap prefixMap) {
out.println("") ;
out.incIndent();
write(out, triple.getSubject(), prefixMap) ;
write(out, triple.getPredicate(), prefixMap) ;
write(out, triple.getObject(), prefixMap) ;
out.decIndent();
out.println(" ") ;
}
static void write(IndentedWriter out, Node node, PrefixMap prefixMap) {
if ( node.isURI() ) {
String uri = node.getURI() ;
// The decent use of TriX is very regular output as we do not use .
// See Notes above.
// if ( false && prefixMap != null ) {
// String abbrev = prefixMap.abbreviate(uri) ;
// if ( abbrev != null ) {
// startTag(out, TriX.tagQName) ;
// writeText(out, abbrev) ;
// endTag(out, TriX.tagQName) ;
// out.println() ;
// return ;
// }
// }
startTag(out, TriX.tagURI) ;
writeText(out, node.getURI()) ;
endTag(out, TriX.tagURI) ;
out.println() ;
return ;
}
if ( node.isBlank() ) {
startTag(out, TriX.tagId) ;
writeText(out, node.getBlankNodeLabel()) ;
endTag(out, TriX.tagId) ;
out.println() ;
return ;
}
if ( node.isLiteral() ) {
// RDF 1.1
String lang = node.getLiteralLanguage() ;
if ( lang != null && lang.isEmpty() )
lang = null ;
String dt = node.getLiteralDatatypeURI() ;
if ( lang != null ) {
startTag(out, TriX.tagPlainLiteral, "xml:lang", lang) ;
writeTextNoIndent(out, node.getLiteralLexicalForm()) ;
endTag(out, TriX.tagPlainLiteral) ;
out.println() ;
return ;
}
if ( dt == null ) {
startTag(out, TriX.tagPlainLiteral) ;
writeTextNoIndent(out, node.getLiteralLexicalForm()) ;
endTag(out, TriX.tagPlainLiteral) ;
out.println() ;
return ;
}
// The case of ( lang == null && dt != null )
startTag(out, TriX.tagTypedLiteral, TriX.attrDatatype, dt) ;
String lex = node.getLiteralLexicalForm() ;
if ( rdfXMLLiteral.equals(dt) ) {
int x = out.getAbsoluteIndent() ;
out.setAbsoluteIndent(0) ;
out.print(lex) ; // Write raw
out.setAbsoluteIndent(x) ;
}
else
writeTextNoIndent(out, lex) ;
endTag(out, TriX.tagTypedLiteral) ;
out.println() ;
return ;
}
throw new RiotException("Not a concrete node: "+node) ;
}
static void writeText(IndentedWriter out, String string) {
string = Util.substituteEntitiesInElementContent(string) ;
out.print(string) ;
}
static void writeTextNoIndent(IndentedWriter out, String string) {
int x = out.getAbsoluteIndent() ;
out.setAbsoluteIndent(0) ;
writeText(out, string) ;
out.setAbsoluteIndent(x) ;
}
static void startXML(IndentedWriter out) {
//out.println("") ;
}
static void startTag(IndentedWriter out, String text) {
out.print("<") ;
out.print(text) ;
out.print(">") ;
out.incIndent();
}
static void startTag(IndentedWriter out, String text, String attr, String attrValue) {
out.print("<") ;
out.print(text) ;
out.print(" ") ;
out.print(attr) ;
out.print("=\"") ;
attrValue = Util.substituteStandardEntities(attrValue) ;
out.print(attrValue) ;
out.print("\"") ;
out.print(">") ;
out.incIndent();
}
static void endTag(IndentedWriter out, String text) {
out.decIndent();
out.print("") ;
}
}
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