/**
* Method to parse a Slot
*
* @param slot Element The XOM element that represents the slot to be parsed.
* @return Returns the data structure that represents the slot in a way that can be used by the
* reasoning engine.
* @throws ParseException Thrown if there is an error parsing the slot.
*/
private Term parseSlot(Element slot) throws ParseException {
Elements children = slot.getChildElements();
Element firstChildName = children.get(0);
boolean dataSlot = false;
if (firstChildName.getLocalName().equals(tagNames.DATA)) {
dataSlot = true;
}
if (!firstChildName.getLocalName().equals(tagNames.IND)
&& !firstChildName.getLocalName().equals(tagNames.DATA)) {
throw new ParseException("In a <slot> only <Ind> and <Data> are allowed.");
}
// Getting the Role from the symbol Table, it will assign one if it
// doesnt already exist
int role = SymbolTable.internRole(firstChildName.getValue().trim());
Element element = children.get(1);
Term term = parseDefaultElement(element);
term.setRole(role);
if (dataSlot) {
term.setDataSlot(true);
}
return term;
}
public DefiniteClause buildResult(Term t) {
if (t.getSymbol() != symbol) {
return null;
}
if (t.subTerms.length != 3) {
return null;
}
Term p2 = t.subTerms[2].deepCopy();
if (p2.getSymbol() < 0) {
return null;
}
if (p2.getType() != Types.IFLOAT && p2.getType() != Types.IINTEGER) {
return null;
}
String p2s = p2.getSymbolString();
double p2d;
try {
p2d = Double.parseDouble(p2s);
} catch (Exception e) {
return null;
}
double result = Math.tan(p2d);
String results = "" + result;
Term r1 = new Term(SymbolTable.internSymbol(results), SymbolTable.INOROLE, Types.IFLOAT);
Term roid =
new Term(SymbolTable.internSymbol("$jdrew-tan-" + p2s), SymbolTable.IOID, Types.ITHING);
Vector v = new Vector();
v.add(roid);
v.add(r1);
v.add(p2);
Term atm = new Term(symbol, SymbolTable.INOROLE, Types.IOBJECT, v);
atm.setAtom(true);
Vector v2 = new Vector();
v2.add(atm);
return new DefiniteClause(v2, new Vector());
}
public DefiniteClause buildResult(Term t) {
if (t.getSymbol() != sym) {
return null;
}
if (t.subTerms.length != 3) {
return null;
}
Term p1 = t.subTerms[1].deepCopy();
Term p2 = t.subTerms[2].deepCopy();
if (p1.getSymbol() < 0 || p2.getSymbol() < 0) {
return null;
}
String p1s = p1.getSymbolString();
String p2s = p2.getSymbolString();
if ((p1.getType() == Types.IFLOAT || p1.getType() == Types.IINTEGER)
&& (p2.getType() == Types.IFLOAT || p2.getType() == Types.IINTEGER)) {
double d1;
double d2;
try {
d1 = Double.parseDouble(p1s);
d2 = Double.parseDouble(p2s);
} catch (Exception e) {
return null;
}
if (d1 > d2) {
return null;
}
} else if (p1.getType() == Types.ISTRING && p2.getType() == Types.ISTRING) {
if (p1s.compareTo(p2s) > 0) {
return null;
}
} else {
return null;
}
Term roid =
new Term(
SymbolTable.internSymbol("$jdrew-lte-" + p1s + "<=" + p2s),
SymbolTable.IOID,
Types.ITHING);
Vector v = new Vector();
v.add(roid);
v.add(p1);
v.add(p2);
Term atm = new Term(sym, SymbolTable.INOROLE, Types.IOBJECT, v);
atm.setAtom(true);
Vector v2 = new Vector();
v2.add(atm);
return new DefiniteClause(v2, new Vector());
}
/**
* Method to parse a Skolem constant
*
* @param sko Element The XOM element that represents the Skolem to be parsed.
* @return Returns the data structure that represents the Skolem in a way that can be used by the
* reasoning engine.
* @throws ParseException Thrown if there is an error parsing the Skolem.
*/
private Term parseSkolem(Element sko) throws ParseException {
String skoname = sko.getValue().trim();
if (skoname.isEmpty()) {
return new Term(
SymbolTable.internSymbol("$gensym" + SymbolTable.genid++),
SymbolTable.INOROLE,
Types.ITHING);
} else {
if (this.skolemMap.containsKey(skoname)) {
String sym = skolemMap.get(skoname);
return new Term(SymbolTable.internSymbol(sym), SymbolTable.INOROLE, Types.ITHING);
} else {
String sym = "$gensym" + (SymbolTable.genid++) + "$" + skoname;
skolemMap.put(skoname, sym);
return new Term(SymbolTable.internSymbol(sym), SymbolTable.INOROLE, Types.ITHING);
}
}
}
/**
* Parse a simple element that just contains plain data (like <Ind> and <Data>).
*
* @param element The element to parse
* @return A Term data structure that represents the element in a way that can be understood by
* the reasoning engine.
* @throws ParseException Thrown if the type specified in the optional type attribute is invalid.
*/
private Term parseSimpleElement(Element element) throws ParseException {
String symbolName = element.getValue().trim();
if (symbolName.isEmpty()) {
symbolName = generateAnonymousIdentifier();
}
int sym = SymbolTable.internSymbol(symbolName);
int typeid = parseTypeAttribute(element);
return new Term(sym, SymbolTable.INOROLE, typeid);
}
/**
* Method to parse a Expr (Expresion)
*
* @param expr Element The XOM element that represents the Expr to be parsed.
* @return Returns the data structure that represents the Expr in a way that can be used by the
* reasoning engine.
* @throws ParseException Thrown if there is an error parsing the Expr.
*/
private Term parseExpression(Element expr) throws ParseException {
Elements children = expr.getChildElements();
Element op = children.get(0);
boolean foundOp = false;
if (op.getLocalName().equals(tagNames.OP)) {
foundOp = true;
}
Element fun = null;
if (foundOp) {
Elements funTag = op.getChildElements();
fun = funTag.get(0);
// Remove <op> element including its child element <Fun>, so
// it will not be parsed twice
expr.removeChild(op);
}
if (!foundOp) {
fun = children.get(0);
// Remove <Fun> element so that it will not be parsed twice
expr.removeChild(fun);
}
if (!fun.getLocalName().equals(tagNames.FUN)) {
throw new ParseException("First child of op in an Expr must be a Fun element.");
}
int symbol = SymbolTable.internSymbol(fun.getValue().trim());
int typeid = parseTypeAttribute(expr);
Vector<Term> subterms = parseDefaultElements(expr);
Term t = new Term(symbol, SymbolTable.INOROLE, typeid, subterms);
return t;
}
/**
* Method to parse an Atom
*
* @param Atom Element The XOM element that represents the Atom to be parsed.
* @param head boolean This tells the engine if the atom is a head of a rule.
* @param neg boolean This tells the engine if the atom is a negative atom (Neg)
* @return Returns the data structure that represents the Atom in a way that can be used by the
* reasoning engine.
* @throws ParseException Thrown if there is an error parsing the Atom.
*/
private Term parseAtom(Element atom, boolean head, boolean neg) throws ParseException {
boolean foundoid = false;
Elements children = atom.getChildElements();
// checking for op tag before the rel
Element op = getFirstChildElement(atom, tagNames.OP);
Element rel = null;
if (op != null) {
Elements relTag = op.getChildElements();
rel = relTag.get(0);
} else {
rel = getFirstChildElement(atom, tagNames.REL);
}
if (rel == null) {
throw new ParseException("In an <Atom>, first child of <op> must be a <Rel>.");
}
String relname = rel.getValue().trim();
if (neg) {
relname = "$neg-" + relname;
}
int symbol = SymbolTable.internSymbol(relname);
Vector<Term> subterms = new Vector<Term>();
int startIndex = getFirstChildElementIndex(children, 0) + 1;
for (int i = startIndex; i < children.size(); i++) {
Element element = children.get(i);
Term term = null;
if (element.getLocalName().equals(tagNames.OID)) {
if (foundoid) {
throw new ParseException("<Atom> must contain a most one <oid>.");
}
term = parseOid(element);
foundoid = true;
} else {
term = parseDefaultElement(element);
}
subterms.add(term);
}
// Generate a fake OID if the atom does not have one.
// This is a requirement put in place by the reasoner.
if (!foundoid) {
if (head) {
String symname = "$gensym" + SymbolTable.genid++;
int symid = SymbolTable.internSymbol(symname);
Term t2 = new Term(symid, SymbolTable.IOID, Types.IOBJECT);
subterms.add(t2);
} else {
String varname = generateAnonymousIdentifier();
int symid = this.internVariable(varname);
Vector<Integer> types = new Vector<Integer>();
types.add(Types.IOBJECT);
this.varClasses.put(symid, types);
Term t2 = new Term(symid, SymbolTable.IOID, Types.IOBJECT);
subterms.add(t2);
}
}
Term t = new Term(symbol, SymbolTable.INOROLE, Types.IOBJECT, subterms);
t.setAtom(true);
return t;
}