// updates the var counts in specified left join index
private void updateLeftJoinNodes(PositionNode node, int finalPos) {
if (node.getNode() instanceof ValueExpr) {
return;
}
int diff = finalPos - node.getPosition();
if (diff == 0) {
return;
}
if (node.isOptional) {
leftJoinPosSet.remove(node);
FlattenedOptional optional = (FlattenedOptional) node.getNode();
if (diff < 0) {
for (int i = node.getPosition() - 1; i > finalPos - 1; i--) {
QueryModelNode tempNode = queryNodes.get(i);
if (tempNode instanceof ValueExpr) {
continue;
}
optional.addArg((TupleExpr) tempNode);
}
} else {
for (int i = node.getPosition() + 1; i < finalPos + 1; i++) {
QueryModelNode tempNode = queryNodes.get(i);
if (tempNode instanceof ValueExpr) {
continue;
}
optional.removeArg((TupleExpr) tempNode);
}
}
node.setNode(optional);
// FlattenedOptional equals does not take into account var counts
// The following three lines update the var count in the optional in list
int index = queryNodes.indexOf(optional);
queryNodes.remove(optional);
queryNodes.add(index, optional);
leftJoinPosSet.add(node);
} else {
TupleExpr te = (TupleExpr) node.getNode();
SortedSet<PositionNode> optionals;
if (diff < 0) {
optionals = leftJoinPosSet.subSet(new PositionNode(finalPos), true, node, false);
for (PositionNode pNode : optionals) {
FlattenedOptional optional = (FlattenedOptional) pNode.getNode();
optional.removeArg(te);
}
} else {
optionals = leftJoinPosSet.subSet(node, false, new PositionNode(finalPos), true);
for (PositionNode pNode : optionals) {
FlattenedOptional optional = (FlattenedOptional) pNode.getNode();
optional.addArg(te);
}
}
}
}
// determine if given node can be moved to finalPos
// assumes node.position and finalPos fall within index range of list
private PositionNode getBounds(
PositionNode node,
int finalPos,
List<QueryModelNode> list,
TreeSet<PositionNode> leftJoinNodes) {
// filters can be moved up and pushed down join segment
// without affecting bound and unbound variables of
// FlattenedOptionals -- Filters can be pushed down as
// far as possible because it is assumed that any variable
// that appears in a Filter also appears in a PCJ node
// if Filters can be grouped, then Filter variables will
// automatically be bound
if (node.getNode() instanceof ValueExpr) {
return new PositionNode();
}
int diff = finalPos - node.getPosition();
if (diff == 0) {
return new PositionNode();
}
if (node.isOptional) {
FlattenedOptional optional = ((FlattenedOptional) node.getNode()).clone();
if (diff < 0) {
for (int i = node.getPosition() - 1; i > finalPos - 1; i--) {
QueryModelNode tempNode = list.get(i);
if (tempNode instanceof ValueExpr) {
continue;
}
if (!optional.canAddTuple((TupleExpr) tempNode)) {
return new PositionNode(tempNode, i);
}
if (tempNode instanceof FlattenedOptional) {
FlattenedOptional tempOptional = (FlattenedOptional) tempNode;
if (!tempOptional.canRemoveTuple(optional)) {
return new PositionNode(tempNode, i);
}
}
optional.addArg((TupleExpr) tempNode);
}
} else {
for (int i = node.getPosition() + 1; i < finalPos + 1; i++) { // TODO
// check
// bounds
QueryModelNode tempNode = list.get(i);
if (tempNode instanceof ValueExpr) {
continue;
}
if (!optional.canRemoveTuple((TupleExpr) tempNode)) {
return new PositionNode(tempNode, i);
}
if (tempNode instanceof FlattenedOptional) {
FlattenedOptional tempOptional = (FlattenedOptional) tempNode;
if (!tempOptional.canAddTuple(optional)) {
return new PositionNode(tempNode, i);
}
}
optional.removeArg((TupleExpr) tempNode);
}
}
return new PositionNode();
} else {
TupleExpr te = (TupleExpr) node.getNode();
SortedSet<PositionNode> leftJoins;
if (diff < 0) {
leftJoins = leftJoinNodes.subSet(new PositionNode(finalPos), true, node, false);
for (PositionNode pNode : leftJoins) {
FlattenedOptional optional = (FlattenedOptional) pNode.getNode();
if (!optional.canRemoveTuple(te)) {
return new PositionNode(pNode);
}
}
} else {
leftJoins = leftJoinNodes.subSet(node, false, new PositionNode(finalPos), true);
for (PositionNode pNode : leftJoins) {
FlattenedOptional optional = (FlattenedOptional) pNode.getNode();
if (!optional.canAddTuple(te)) {
return new PositionNode(pNode);
}
}
}
return new PositionNode();
}
}
