private void createIteration() throws QueryEvaluationException {
if (currentLength == 0L) {
ZeroLengthPath zlp = new ZeroLengthPath(scope, startVar, endVar, contextVar);
currentIter = this.evaluationStrategyImpl.evaluate(zlp, bindings);
currentLength++;
} else if (currentLength == 1) {
TupleExpr pathExprClone = pathExpression.clone();
if (startVarFixed && endVarFixed) {
Var replacement =
createAnonVar(JOINVAR_PREFIX + currentLength + "-" + pathExpression.hashCode());
VarReplacer replacer = new VarReplacer(endVar, replacement, 0, false);
pathExprClone.visit(replacer);
}
currentIter = this.evaluationStrategyImpl.evaluate(pathExprClone, bindings);
currentLength++;
} else {
currentVp = valueQueue.poll();
if (currentVp != null) {
TupleExpr pathExprClone = pathExpression.clone();
if (startVarFixed && endVarFixed) {
Var startReplacement =
createAnonVar(JOINVAR_PREFIX + currentLength + "-" + pathExpression.hashCode());
Var endReplacement = createAnonVar("END_" + JOINVAR_PREFIX + pathExpression.hashCode());
startReplacement.setAnonymous(false);
endReplacement.setAnonymous(false);
Value v = currentVp.getEndValue();
startReplacement.setValue(v);
VarReplacer replacer = new VarReplacer(startVar, startReplacement, 0, false);
pathExprClone.visit(replacer);
replacer = new VarReplacer(endVar, endReplacement, 0, false);
pathExprClone.visit(replacer);
} else {
Var toBeReplaced;
Value v;
if (!endVarFixed) {
toBeReplaced = startVar;
v = currentVp.getEndValue();
} else {
toBeReplaced = endVar;
v = currentVp.getStartValue();
}
Var replacement =
createAnonVar(JOINVAR_PREFIX + currentLength + "-" + pathExpression.hashCode());
replacement.setValue(v);
VarReplacer replacer = new VarReplacer(toBeReplaced, replacement, 0, false);
pathExprClone.visit(replacer);
}
currentIter = this.evaluationStrategyImpl.evaluate(pathExprClone, bindings);
} else {
currentIter = new EmptyIteration<BindingSet, QueryEvaluationException>();
}
currentLength++;
}
}