How to use it.unibz.inf.ontop.datalog

private boolean hasSelectDistinctStatement(DatalogProgram query) {
  boolean toReturn = false;
  if (query.getQueryModifiers().hasModifiers()) {
    toReturn = query.getQueryModifiers().isDistinct();
  }
  return toReturn;
}

/***
 * This expands all Join that can be directly added as conjuncts to a
 * query's body. Nested Join trees inside left joins are not touched.
 * 
 * @param query
 * @return
 */
public static void unfoldJoinTrees(CQIE query) {
  unfoldJoinTrees(query.getBody(), true);
}

public static DatalogProgram program(Collection<CQIE> rules){
  DatalogProgram datalogProgram = DATALOG_FACTORY.getDatalogProgram();
  datalogProgram.appendRule(rules);
  return datalogProgram;
}

private boolean hasOrderByClause(DatalogProgram query) {
  boolean toReturn = false;
  if (query.getQueryModifiers().hasModifiers()) {
    final List<OrderCondition> conditions = query.getQueryModifiers()
        .getSortConditions();
    toReturn = (!conditions.isEmpty());
  }
  return toReturn;
}

@Override
public DatalogProgram getDatalogProgram(MutableQueryModifiers modifiers, Collection<CQIE> rules) {
  DatalogProgram p = new DatalogProgramImpl();
  p.appendRule(rules);
  p.getQueryModifiers().copy(modifiers);
  return p;
}

public int getMaxQuerySizeAfterRewriting() {
int toReturn = Integer.MIN_VALUE;
if( sizesCollected() ){
  List<CQIE> rules = programAfterRewriting.getRules();
  for (CQIE rule : rules) {
  int querySize = getBodySize(rule.getBody());
  if (querySize > toReturn) {
    toReturn = querySize;
  }
  }
}
return toReturn;
}

private void appendRule(Function head, List<Function> body) {
  CQIE rule = datalogFactory.getCQIE(head, body);
  program.appendRule(rule);
}

public void foldJoinTrees(CQIE query) {
  foldJoinTrees(query.getBody(), false);
}

public static void addMinimalEqualityToLeftJoin(CQIE query) {
  for (Function f : query.getBody()) {
    if (f.isAlgebraFunction()) {
      addMinimalEqualityToLeftJoin(f);
    }
  }
}

/***
 * Adds a trivial equality to a LeftJoin in case the left join doesn't have
 * at least one boolean condition. This is necessary to have syntactically
 * correct LeftJoins in SQL.
 */
public void addMinimalEqualityToLeftOrNestedInnerJoin(CQIE query) {
  for (Function f : query.getBody()) {
    if (f.isAlgebraFunction()) {
      addMinimalEqualityToLeftOrNestedInnerJoin(f);
    }
  }
}

@Override
public DatalogProgram clone() {
  DatalogProgramImpl clone = new DatalogProgramImpl();
  for (CQIE query : rules) {
    clone.appendRule(query.clone());
  }
  clone.modifiers = modifiers.clone();
  return clone;
}

@Override
public DatalogProgram getDatalogProgram(MutableQueryModifiers modifiers) {
  DatalogProgram p = new DatalogProgramImpl();
  p.getQueryModifiers().copy(modifiers);
  return p;
}

/**
 * Normalizations of the Datalog program requirend by the Datalog to SQL translator
 */
private void normalizeRule(CQIE cq) {
  DatalogNormalizer.foldJoinTrees(cq);
  DatalogNormalizer.addMinimalEqualityToLeftJoin(cq);
}

  @Override
  public boolean hasModifiers() {
    return modifiers.hasModifiers();
  }
}

  @Override
  public Function f(Function firstAtom, Function secondAtom) {
    return DATALOG_FACTORY.getSPARQLJoin(firstAtom, secondAtom, TRUE_EQ);
  }
}, firstAtom);

/**
 * Rule-level variable generator.
 */
public VariableGenerator(CQIE initialRule) {
  count = 0;
  knownVariables = initialRule.getReferencedVariables();
}

private void subscribeHeadTerms(Function head) {
  if (head instanceof ListenableFunction) {
    EventGeneratingList<Term> headterms = ((ListenableFunction)head).getTerms();
    headterms.addListener(this);
  }
  else if (!(head instanceof ImmutableFunctionalTerm)) {
    throw new RuntimeException("Unknown type of function: not listenable nor immutable:  "
        + head);
  }
}

  @Override
  public String toString() {
    if (dependencies != null)
      return dependencies.toString();
    
    return "(empty)";
  }
}

public static void foldJoinTrees(CQIE query) {
  foldJoinTrees(query.getBody(), false);
}

@Override
public DatalogProgram clone() {
  DatalogProgramImpl clone = new DatalogProgramImpl();
  for (CQIE query : rules) {
    clone.appendRule(query.clone());
  }
  clone.modifiers = modifiers.clone();
  return clone;
}