@Override
public QueryResult process(final QueryResult bindings, final int operandID) {
if (operandID < this.operandResults.length) {
this.operandResults[operandID] = bindings;
} else
System.err.println(
"NAryMergeJoin is a "
+ this.operandResults.length
+ "-ary operator, but received the operand number "
+ operandID);
boolean go = true;
for (int i = 0; i < this.operandResults.length; i++) {
if (this.operandResults[i] == null) {
go = false;
break;
}
}
if (go) {
this.comp.setVariables(this.intersectionVariables);
if (this.minimum == null) return null;
@SuppressWarnings("unchecked")
final Iterator<Bindings>[] itb = new Iterator[this.operandResults.length];
for (int i = 0; i < this.operandResults.length; i++) {
itb[i] = this.operandResults[i].oneTimeIterator();
}
final ParallelIterator<Bindings> currentResult =
(this.intersectionVariables.size() == 0)
? MergeJoin.cartesianProductIterator(this.operandResults)
: MergeJoin.mergeJoinIterator(
itb, this.comp, this.intersectionVariables, this.minimum, this.maximum);
if (currentResult != null && currentResult.hasNext()) {
final QueryResult result =
QueryResult.createInstance(
new SIPParallelIterator<Bindings, Bindings>() {
int number = 0;
@Override
public void close() {
currentResult.close();
}
@Override
public boolean hasNext() {
if (!currentResult.hasNext()) {
NAryMergeJoinWithoutSorting.this.realCardinality = this.number;
close();
}
return currentResult.hasNext();
}
@Override
public Bindings next() {
final Bindings b = currentResult.next();
if (b != null) this.number++;
if (!currentResult.hasNext()) {
NAryMergeJoinWithoutSorting.this.realCardinality = this.number;
close();
}
return b;
}
public Bindings getNext(final Bindings k) {
@SuppressWarnings("unchecked")
final Bindings b =
((SIPParallelIterator<Bindings, Bindings>) currentResult).next(k);
if (b != null) this.number++;
if (!currentResult.hasNext()) {
NAryMergeJoinWithoutSorting.this.realCardinality = this.number;
close();
}
return b;
}
@Override
public void remove() {
currentResult.remove();
}
@Override
public void finalize() {
close();
}
@Override
public Bindings next(final Bindings k) {
if (currentResult instanceof SIPParallelIterator) return getNext(k);
else return next();
}
});
return result;
} else {
for (int i = 0; i < this.operandResults.length; i++) {
if (this.operandResults[i] != null) {
this.operandResults[i].release();
this.operandResults[i] = null;
}
}
return null;
}
} else {
return null;
}
}
@SuppressWarnings("unchecked")
@Override
public QueryResult process(final QueryResult bindings, final int operandID) {
bindings.materialize();
this.comp.setVariables(this.intersectionVariables);
final QueryResult oldLeft = this.left;
final QueryResult oldRight = this.right;
if (operandID == 0) {
if (this.left == null) this.left = bindings;
else
this.left =
QueryResult.createInstance(
new MergeIterator<Bindings>(this.comp, this.left.iterator(), bindings.iterator()));
} else if (operandID == 1) {
if (this.right == null) this.right = bindings;
else
this.right =
QueryResult.createInstance(
new MergeIterator<Bindings>(this.comp, this.right.iterator(), bindings.iterator()));
} else
System.err.println(
"MergeJoin is a binary operator, but received the operand number " + operandID);
if (this.left != null && this.right != null) {
this.left.materialize();
this.right.materialize();
final Iterator<Bindings> leftIterator =
(operandID == 0 && oldLeft != null)
? new MinusIterator(bindings.iterator(), oldLeft.iterator())
: this.left.iterator();
final QueryResult rightLocal =
(operandID == 1 && oldRight != null)
? QueryResult.createInstance(
new MinusIterator(bindings.iterator(), oldRight.iterator()))
: this.right;
final ParallelIterator<Bindings> currentResult =
(this.intersectionVariables.size() == 0)
? MergeJoin.cartesianProductIterator(leftIterator, rightLocal)
: MergeJoin.mergeJoinIterator(
leftIterator, rightLocal.iterator(), this.comp, this.intersectionVariables);
if (currentResult != null && currentResult.hasNext()) {
final QueryResult result =
QueryResult.createInstance(
new ParallelIterator<Bindings>() {
int number = 0;
@Override
public void close() {
currentResult.close();
}
@Override
public boolean hasNext() {
if (!currentResult.hasNext()) {
MergeJoinWithoutSortingSeveralIterations.this.realCardinality = this.number;
close();
}
return currentResult.hasNext();
}
@Override
public Bindings next() {
final Bindings b = currentResult.next();
if (!currentResult.hasNext()) {
MergeJoinWithoutSortingSeveralIterations.this.realCardinality = this.number;
close();
}
if (b != null) this.number++;
return b;
}
@Override
public void remove() {
currentResult.remove();
}
@Override
public void finalize() {
close();
}
});
return result;
} else {
return null;
}
} else {
return null;
}
}