/*
* 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.openjena.riot.lang;
import static org.openjena.riot.tokens.TokenType.DOT ;
import static org.openjena.riot.tokens.TokenType.RBRACE ;
import org.openjena.atlas.lib.Sink ;
import org.openjena.riot.Lang ;
import org.openjena.riot.system.ParserProfile ;
import org.openjena.riot.tokens.Token ;
import org.openjena.riot.tokens.TokenType ;
import org.openjena.riot.tokens.Tokenizer ;
import com.hp.hpl.jena.graph.Node ;
import com.hp.hpl.jena.sparql.core.Quad ;
/** TriG language: http://www4.wiwiss.fu-berlin.de/bizer/TriG/
* Generalizations:
* Can have multiple default graph blocks.
*
*
*/
public class LangTriG extends LangTurtleBase<Quad>
{
/*
TriGDoc ::= ws* (statement ws*)*
statement ::= directive ws* '.' | graph
graph ::= graphName? ws* '='? ws* '{' ws* (triples ws* ('.' ws* triples ws*)* '.'? ws*)? '}' ws* '.'?
graphName ::= resource
We may add:
statement ::= directive ws* '.' | graph | quad
quad ::= subject predicate object resource?
(i.e. raw inline nquads except with preifx names.
*/
public LangTriG(String baseURI, Tokenizer tokens,
ParserProfile profile,
Sink<Quad> sink)
{
super(baseURI, tokens, profile, sink) ;
}
@Override
public Lang getLang() { return Lang.TRIG ; }
@Override
protected final void oneTopLevelElement()
{
oneNamedGraphBlock() ;
}
protected final void oneNamedGraphBlock()
{
// Directives are only between graphs.
Node graphNode = Quad.tripleInQuad ;
Token token = peekToken() ;
// <foo> = { ... } .
if ( token.isNode() )
{
Token t = token ; // Keep for error message.
graphNode = node() ;
nextToken() ;
token = peekToken() ;
if ( graphNode.isURI() )
setCurrentGraph(graphNode) ;
else
exception(t, "Not a legal graph name: "+graphNode) ;
}
else
setCurrentGraph(Quad.tripleInQuad) ;
// = is optional
if ( token.getType() == TokenType.EQUALS )
{
// Skip.
nextToken() ;
token = peekToken() ;
}
if ( token.getType() != TokenType.LBRACE )
exception(token, "Expected start of graph: got %s", peekToken()) ;
nextToken() ;
// **** Turtle but no directives.
while(true)
{
token = peekToken() ;
if ( token.hasType(TokenType.RBRACE) )
break ;
// No - this has Turtle termination rules.
// Assume this is fixed then ....
// Unlike many operations in this parser suite
// this does not assume that we are definitel entering
// this sttae throws an error if the first token
triplesSameSubject() ;
}
// **** Turtle.
token = nextToken() ;
if ( token.getType() != TokenType.RBRACE )
exception(token, "Expected end of graph: got %s", token) ;
// Skip DOT
token = peekToken() ;
if ( token.hasType(TokenType.DOT) )
nextToken() ;
// End graph block.
setCurrentGraph(Quad.tripleInQuad) ;
}
@Override
protected void expectEndOfTriples()
{
// The DOT is required by Turtle (strictly).
// It is not in N3 and SPARQL.
if ( strict )
{
expect("Triples not terminated by DOT", DOT) ;
return ;
}
if ( lookingAt(DOT) )
{
nextToken() ;
return ;
}
// Loose - DOT optional.
if ( lookingAt(RBRACE) )
// Don't consume the RBRACE
return ;
exception(peekToken(), "Triples not terminated properly: expected '.', '}' or EOF: got %s", peekToken()) ;
}
@Override
protected void emit(Node subject, Node predicate, Node object)
{
Node graph = getCurrentGraph() ;
if ( graph == Quad.defaultGraphNodeGenerated )
graph = Quad.tripleInQuad ;
Quad quad = profile.createQuad(graph, subject, predicate, object, currLine, currCol) ;
sink.send(quad) ;
}
}