package com.github.jsonldjava.impl;
import static com.github.jsonldjava.core.JsonLdConsts.RDF_FIRST;
import static com.github.jsonldjava.core.JsonLdConsts.RDF_LANGSTRING;
import static com.github.jsonldjava.core.JsonLdConsts.RDF_NIL;
import static com.github.jsonldjava.core.JsonLdConsts.RDF_REST;
import static com.github.jsonldjava.core.JsonLdConsts.RDF_TYPE;
import static com.github.jsonldjava.core.JsonLdConsts.XSD_BOOLEAN;
import static com.github.jsonldjava.core.JsonLdConsts.XSD_DECIMAL;
import static com.github.jsonldjava.core.JsonLdConsts.XSD_DOUBLE;
import static com.github.jsonldjava.core.JsonLdConsts.XSD_INTEGER;
import static com.github.jsonldjava.core.RDFDatasetUtils.unescape;
import static com.github.jsonldjava.core.Regex.BLANK_NODE_LABEL;
import static com.github.jsonldjava.core.Regex.DECIMAL;
import static com.github.jsonldjava.core.Regex.DOUBLE;
import static com.github.jsonldjava.core.Regex.INTEGER;
import static com.github.jsonldjava.core.Regex.IRIREF;
import static com.github.jsonldjava.core.Regex.LANGTAG;
import static com.github.jsonldjava.core.Regex.PNAME_LN;
import static com.github.jsonldjava.core.Regex.PNAME_NS;
import static com.github.jsonldjava.core.Regex.STRING_LITERAL_LONG_QUOTE;
import static com.github.jsonldjava.core.Regex.STRING_LITERAL_LONG_SINGLE_QUOTE;
import static com.github.jsonldjava.core.Regex.STRING_LITERAL_QUOTE;
import static com.github.jsonldjava.core.Regex.STRING_LITERAL_SINGLE_QUOTE;
import static com.github.jsonldjava.core.Regex.UCHAR;
import static com.github.jsonldjava.core.Regex.WS;
import static com.github.jsonldjava.core.Regex.WS_0_N;
import static com.github.jsonldjava.core.Regex.WS_1_N;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Stack;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import com.github.jsonldjava.core.JsonLdError;
import com.github.jsonldjava.core.RDFDataset;
import com.github.jsonldjava.core.RDFParser;
import com.github.jsonldjava.core.UniqueNamer;
/**
* A (probably terribly slow) Parser for turtle. Turtle is the internal
* RDFDataset used by JSOND-Java
*
* TODO: this probably needs to be changed to use a proper parser/lexer
*
* @author Tristan
*
*/
public class TurtleRDFParser implements RDFParser {
static class Regex {
final public static Pattern PREFIX_ID = Pattern.compile("@prefix" + WS_1_N + PNAME_NS
+ WS_1_N + IRIREF + WS_0_N + "\\." + WS_0_N);
final public static Pattern BASE = Pattern.compile("@base" + WS_1_N + IRIREF + WS_0_N
+ "\\." + WS_0_N);
final public static Pattern SPARQL_PREFIX = Pattern.compile("[Pp][Rr][Ee][Ff][Ii][Xx]" + WS
+ PNAME_NS + WS + IRIREF + WS_0_N);
final public static Pattern SPARQL_BASE = Pattern.compile("[Bb][Aa][Ss][Ee]" + WS + IRIREF
+ WS_0_N);
final public static Pattern PREFIXED_NAME = Pattern.compile("(?:" + PNAME_LN + "|"
+ PNAME_NS + ")");
final public static Pattern IRI = Pattern.compile("(?:" + IRIREF + "|" + PREFIXED_NAME
+ ")");
final public static Pattern ANON = Pattern.compile("(?:\\[" + WS + "*\\])");
final public static Pattern BLANK_NODE = Pattern.compile(BLANK_NODE_LABEL + "|" + ANON);
final public static Pattern STRING = Pattern.compile("(" + STRING_LITERAL_LONG_SINGLE_QUOTE
+ "|" + STRING_LITERAL_LONG_QUOTE + "|" + STRING_LITERAL_QUOTE + "|"
+ STRING_LITERAL_SINGLE_QUOTE + ")");
final public static Pattern BOOLEAN_LITERAL = Pattern.compile("(true|false)");
final public static Pattern RDF_LITERAL = Pattern.compile(STRING + "(?:" + LANGTAG
+ "|\\^\\^" + IRI + ")?");
final public static Pattern NUMERIC_LITERAL = Pattern.compile("(" + DOUBLE + ")|("
+ DECIMAL + ")|(" + INTEGER + ")");
final public static Pattern LITERAL = Pattern.compile(RDF_LITERAL + "|" + NUMERIC_LITERAL
+ "|" + BOOLEAN_LITERAL);
final public static Pattern DIRECTIVE = Pattern.compile("^(?:" + PREFIX_ID + "|" + BASE
+ "|" + SPARQL_PREFIX + "|" + SPARQL_BASE + ")");
final public static Pattern SUBJECT = Pattern.compile("^" + IRI + "|" + BLANK_NODE);
final public static Pattern PREDICATE = Pattern.compile("^" + IRI + "|a" + WS_1_N);
final public static Pattern OBJECT = Pattern.compile("^" + IRI + "|" + BLANK_NODE + "|"
+ LITERAL);
// others
// final public static Pattern WS_AT_LINE_START = Pattern.compile("^" +
// WS_1_N);
final public static Pattern EOLN = Pattern.compile("(?:\r\n)|(?:\n)|(?:\r)");
final public static Pattern NEXT_EOLN = Pattern.compile("^.*(?:" + EOLN + ")" + WS_0_N);
// final public static Pattern EMPTY_LINE = Pattern.compile("^" + WS +
// "*$");
final public static Pattern COMMENT_OR_WS = Pattern.compile("^(?:(?:[#].*(?:" + EOLN + ")"
+ WS_0_N + ")|(?:" + WS_1_N + "))");
}
private class State {
String baseIri = "";
Map<String, String> namespaces = new LinkedHashMap<String, String>();
String curSubject = null;
String curPredicate = null;
String line = null;
int lineNumber = 0;
int linePosition = 0;
// int bnodes = 0;
UniqueNamer namer = new UniqueNamer("_:b");// {{ getName(); }}; // call
// getName() after
// construction to make
// first active bnode _:b1
private final Stack<Map<String, String>> stack = new Stack<Map<String, String>>();
public boolean expectingBnodeClose = false;
public State(String input) throws JsonLdError {
line = input;
lineNumber = 1;
advanceLinePosition(0);
}
public void push() {
stack.push(new LinkedHashMap<String, String>() {
{
put(curSubject, curPredicate);
}
});
expectingBnodeClose = true;
curSubject = null;
curPredicate = null;
}
public void pop() {
if (stack.size() > 0) {
for (final Entry<String, String> x : stack.pop().entrySet()) {
curSubject = x.getKey();
curPredicate = x.getValue();
}
}
if (stack.size() == 0) {
expectingBnodeClose = false;
}
}
private void advanceLineNumber() throws JsonLdError {
final Matcher match = Regex.NEXT_EOLN.matcher(line);
if (match.find()) {
final String[] split = match.group(0).split("" + Regex.EOLN);
lineNumber += (split.length - 1);
linePosition += split[split.length - 1].length();
line = line.substring(match.group(0).length());
}
}
public void advanceLinePosition(int len) throws JsonLdError {
if (len > 0) {
linePosition += len;
line = line.substring(len);
}
while (!"".equals(line)) {
// clear any whitespace
final Matcher match = Regex.COMMENT_OR_WS.matcher(line);
if (match.find() && match.group(0).length() > 0) {
final Matcher eoln = Regex.EOLN.matcher(match.group(0));
int end = 0;
while (eoln.find()) {
lineNumber += 1;
end = eoln.end();
}
linePosition = match.group(0).length() - end;
line = line.substring(match.group(0).length());
} else {
break;
}
}
if ("".equals(line) && !endIsOK()) {
throw new JsonLdError(JsonLdError.Error.PARSE_ERROR,
"Error while parsing Turtle; unexpected end of input. {line: " + lineNumber
+ ", position:" + linePosition + "}");
}
}
private boolean endIsOK() {
return curSubject == null && stack.size() == 0;
}
public String expandIRI(String ns, String name) throws JsonLdError {
if (namespaces.containsKey(ns)) {
return namespaces.get(ns) + name;
} else {
throw new JsonLdError(JsonLdError.Error.PARSE_ERROR, "No prefix found for: " + ns
+ " {line: " + lineNumber + ", position:" + linePosition + "}");
}
}
}
@Override
public RDFDataset parse(Object input) throws JsonLdError {
if (!(input instanceof String)) {
throw new JsonLdError(JsonLdError.Error.INVALID_INPUT,
"Invalid input; Triple RDF Parser requires a string input");
}
final RDFDataset result = new RDFDataset();
final State state = new State((String) input);
while (!"".equals(state.line)) {
// check if line is a directive
Matcher match = Regex.DIRECTIVE.matcher(state.line);
if (match.find()) {
if (match.group(1) != null || match.group(4) != null) {
final String ns = match.group(1) != null ? match.group(1) : match.group(4);
String iri = match.group(1) != null ? match.group(2) : match.group(5);
if (!iri.contains(":")) {
iri = state.baseIri + iri;
}
iri = unescape(iri);
validateIRI(state, iri);
state.namespaces.put(ns, iri);
result.setNamespace(ns, iri);
} else {
String base = match.group(3) != null ? match.group(3) : match.group(6);
base = unescape(base);
validateIRI(state, base);
if (!base.contains(":")) {
state.baseIri = state.baseIri + base;
} else {
state.baseIri = base;
}
}
state.advanceLinePosition(match.group(0).length());
continue;
}
if (state.curSubject == null) {
// we need to match a subject
match = Regex.SUBJECT.matcher(state.line);
if (match.find()) {
String iri;
if (match.group(1) != null) {
// matched IRI
iri = unescape(match.group(1));
if (!iri.contains(":")) {
iri = state.baseIri + iri;
}
} else if (match.group(2) != null) {
// matched NS:NAME
final String ns = match.group(2);
final String name = unescapeReserved(match.group(3));
iri = state.expandIRI(ns, name);
} else if (match.group(4) != null) {
// match ns: only
iri = state.expandIRI(match.group(4), "");
} else if (match.group(5) != null) {
// matched BNODE
iri = state.namer.getName(match.group(0).trim());
} else {
// matched anon node
iri = state.namer.getName();
}
// make sure IRI still matches an IRI after escaping
validateIRI(state, iri);
state.curSubject = iri;
state.advanceLinePosition(match.group(0).length());
}
// handle blank nodes
else if (state.line.startsWith("[")) {
final String bnode = state.namer.getName();
state.advanceLinePosition(1);
state.push();
state.curSubject = bnode;
}
// handle collections
else if (state.line.startsWith("(")) {
final String bnode = state.namer.getName();
// so we know we want a predicate if the collection close
// isn't followed by a subject end
state.curSubject = bnode;
state.advanceLinePosition(1);
state.push();
state.curSubject = bnode;
state.curPredicate = RDF_FIRST;
}
// make sure we have a subject already
else {
throw new JsonLdError(JsonLdError.Error.PARSE_ERROR,
"Error while parsing Turtle; missing expected subject. {line: "
+ state.lineNumber + "position: " + state.linePosition + "}");
}
}
if (state.curPredicate == null) {
// match predicate
match = Regex.PREDICATE.matcher(state.line);
if (match.find()) {
String iri = "";
if (match.group(1) != null) {
// matched IRI
iri = unescape(match.group(1));
if (!iri.contains(":")) {
iri = state.baseIri + iri;
}
} else if (match.group(2) != null) {
// matched NS:NAME
final String ns = match.group(2);
final String name = unescapeReserved(match.group(3));
iri = state.expandIRI(ns, name);
} else if (match.group(4) != null) {
// matched ns:
iri = state.expandIRI(match.group(4), "");
} else {
// matched "a"
iri = RDF_TYPE;
}
validateIRI(state, iri);
state.curPredicate = iri;
state.advanceLinePosition(match.group(0).length());
} else {
throw new JsonLdError(JsonLdError.Error.PARSE_ERROR,
"Error while parsing Turtle; missing expected predicate. {line: "
+ state.lineNumber + "position: " + state.linePosition + "}");
}
}
// expecting bnode or object
// match BNODE values
if (state.line.startsWith("[")) {
final String bnode = state.namer.getName();
result.addTriple(state.curSubject, state.curPredicate, bnode);
state.advanceLinePosition(1);
// check for anonymous objects
if (state.line.startsWith("]")) {
state.advanceLinePosition(1);
// next we expect a statement or object separator
}
// otherwise we're inside the blank node
else {
state.push();
state.curSubject = bnode;
// next we expect a predicate
continue;
}
}
// match collections
else if (state.line.startsWith("(")) {
state.advanceLinePosition(1);
// check for empty collection
if (state.line.startsWith(")")) {
state.advanceLinePosition(1);
result.addTriple(state.curSubject, state.curPredicate, RDF_NIL);
// next we expect a statement or object separator
}
// otherwise we're inside the collection
else {
final String bnode = state.namer.getName();
result.addTriple(state.curSubject, state.curPredicate, bnode);
state.push();
state.curSubject = bnode;
state.curPredicate = RDF_FIRST;
continue;
}
} else {
// match object
match = Regex.OBJECT.matcher(state.line);
if (match.find()) {
String iri = null;
if (match.group(1) != null) {
// matched IRI
iri = unescape(match.group(1));
if (!iri.contains(":")) {
iri = state.baseIri + iri;
}
} else if (match.group(2) != null) {
// matched NS:NAME
final String ns = match.group(2);
final String name = unescapeReserved(match.group(3));
iri = state.expandIRI(ns, name);
} else if (match.group(4) != null) {
// matched ns:
iri = state.expandIRI(match.group(4), "");
} else if (match.group(5) != null) {
// matched BNODE
iri = state.namer.getName(match.group(0).trim());
}
if (iri != null) {
validateIRI(state, iri);
// we have a object
result.addTriple(state.curSubject, state.curPredicate, iri);
} else {
// we have a literal
String value = match.group(6);
String lang = null;
String datatype = null;
if (value != null) {
// we have a string literal
value = unquoteString(value);
value = unescape(value);
lang = match.group(7);
if (lang == null) {
if (match.group(8) != null) {
datatype = unescape(match.group(8));
if (!datatype.contains(":")) {
datatype = state.baseIri + datatype;
}
validateIRI(state, datatype);
} else if (match.group(9) != null) {
datatype = state.expandIRI(match.group(9),
unescapeReserved(match.group(10)));
} else if (match.group(11) != null) {
datatype = state.expandIRI(match.group(11), "");
}
} else {
datatype = RDF_LANGSTRING;
}
} else if (match.group(12) != null) {
// integer literal
value = match.group(12);
datatype = XSD_DOUBLE;
} else if (match.group(13) != null) {
// decimal literal
value = match.group(13);
datatype = XSD_DECIMAL;
} else if (match.group(14) != null) {
// double literal
value = match.group(14);
datatype = XSD_INTEGER;
} else if (match.group(15) != null) {
// boolean literal
value = match.group(15);
datatype = XSD_BOOLEAN;
}
result.addTriple(state.curSubject, state.curPredicate, value, datatype,
lang);
}
state.advanceLinePosition(match.group(0).length());
} else {
throw new JsonLdError(JsonLdError.Error.PARSE_ERROR,
"Error while parsing Turtle; missing expected object or blank node. {line: "
+ state.lineNumber + "position: " + state.linePosition + "}");
}
}
// close collection
boolean collectionClosed = false;
while (state.line.startsWith(")")) {
if (!RDF_FIRST.equals(state.curPredicate)) {
throw new JsonLdError(JsonLdError.Error.PARSE_ERROR,
"Error while parsing Turtle; unexpected ). {line: " + state.lineNumber
+ "position: " + state.linePosition + "}");
}
result.addTriple(state.curSubject, RDF_REST, RDF_NIL);
state.pop();
state.advanceLinePosition(1);
collectionClosed = true;
}
boolean expectDotOrPred = false;
// match end of bnode
if (state.line.startsWith("]")) {
final String bnode = state.curSubject;
state.pop();
state.advanceLinePosition(1);
if (state.curSubject == null) {
// this is a bnode as a subject and we
// expect either a . or a predicate
state.curSubject = bnode;
expectDotOrPred = true;
}
}
// match list separator
if (!expectDotOrPred && state.line.startsWith(",")) {
state.advanceLinePosition(1);
// now we expect another object/bnode
continue;
}
// match predicate end
if (!expectDotOrPred) {
while (state.line.startsWith(";")) {
state.curPredicate = null;
state.advanceLinePosition(1);
// now we expect another predicate, or a dot
expectDotOrPred = true;
}
}
if (state.line.startsWith(".")) {
if (state.expectingBnodeClose) {
throw new JsonLdError(JsonLdError.Error.PARSE_ERROR,
"Error while parsing Turtle; missing expected )\"]\". {line: "
+ state.lineNumber + "position: " + state.linePosition + "}");
}
state.curSubject = null;
state.curPredicate = null;
state.advanceLinePosition(1);
// this can now be the end of the document.
continue;
} else if (expectDotOrPred) {
// we're expecting another predicate since we didn't find a dot
continue;
}
// if we're in a collection
if (RDF_FIRST.equals(state.curPredicate)) {
final String bnode = state.namer.getName();
result.addTriple(state.curSubject, RDF_REST, bnode);
state.curSubject = bnode;
continue;
}
if (collectionClosed) {
// we expect another object
// TODO: it's not clear yet if this is valid
continue;
}
// if we get here, we're missing a close statement
throw new JsonLdError(JsonLdError.Error.PARSE_ERROR,
"Error while parsing Turtle; missing expected \"]\" \",\" \";\" or \".\". {line: "
+ state.lineNumber + "position: " + state.linePosition + "}");
}
return result;
}
final public static Pattern IRIREF_MINUS_CONTAINER = Pattern
.compile("(?:(?:[^\\x00-\\x20<>\"{}|\\^`\\\\]|" + UCHAR + ")*)|" + Regex.PREFIXED_NAME);
private void validateIRI(State state, String iri) throws JsonLdError {
if (!IRIREF_MINUS_CONTAINER.matcher(iri).matches()) {
throw new JsonLdError(JsonLdError.Error.PARSE_ERROR,
"Error while parsing Turtle; invalid IRI after escaping. {line: "
+ state.lineNumber + "position: " + state.linePosition + "}");
}
}
final private static Pattern PN_LOCAL_ESC_MATCHED = Pattern
.compile("[\\\\]([_~\\.\\-!$&'\\(\\)*+,;=/?#@%])");
static String unescapeReserved(String str) {
if (str != null) {
final Matcher m = PN_LOCAL_ESC_MATCHED.matcher(str);
if (m.find()) {
return m.replaceAll("$1");
}
}
return str;
}
private String unquoteString(String value) {
if (value.startsWith("\"\"\"") || value.startsWith("'''")) {
return value.substring(3, value.length() - 3);
} else if (value.startsWith("\"") || value.startsWith("'")) {
return value.substring(1, value.length() - 1);
}
return value;
}
}