/**
* put braces around single member or single tuple
*
* @param oExp
* @return set exp
*/
private Exp bracesAround(Exp oExp) {
Exp oSet;
if (quaxUtil.isMember(oExp) || quaxUtil.isFunCallTo(oExp, "()")) {
FunCall call = new FunCall("{}", Syntax.Braces);
call.getArgs().add(oExp);
oSet = call;
} else {
oSet = oExp;
}
return oSet;
}
/**
* generate Tuple Exp
*
* @param node
* @return
*/
private Exp[] genTuple(TreeNode<Exp> node) {
if (!quaxUtil.isMember(node.getReference())) {
return null;
}
int size = nDimension - node.getLevel() + 1;
if (size == 1) {
// single member
return new Exp[] {node.getReference()};
}
List<TreeNode<Exp>> childNodes = node.getChildren();
if (childNodes.size() != 1) {
return null;
}
Exp[] nextTuple = genTuple(childNodes.get(0));
if (nextTuple == null) {
return null;
}
Exp[] tupleMembers = new Exp[size];
tupleMembers[0] = node.getReference();
for (int i = 1; i < tupleMembers.length; i++) {
tupleMembers[i] = nextTuple[i - 1];
}
return tupleMembers;
}
/**
* Recursively generate Exp for a node
*
* @param node
* @return
*/
private Exp genExpForNode(TreeNode<Exp> node, int untilIndex) {
Exp eNode = node.getReference();
if (node.getLevel() == untilIndex) {
// last dimension
return eNode;
}
// use tuple representation if possible
Exp[] tuple = genTuple(node);
if (tuple != null) {
if (tuple.length == 1) {
return tuple[0];
} else {
return new FunCall("()", Syntax.Parentheses, Arrays.asList(tuple));
}
}
// generate CrossJoin
Exp exp = null;
List<TreeNode<Exp>> childNodes = node.getChildren();
for (TreeNode<Exp> childNode : childNodes) {
Exp childExp = genExpForNode(childNode, untilIndex);
Exp eSet;
if (!quaxUtil.isMember(eNode)) {
// FunCall
eSet = eNode;
} else {
// member
FunCall call = new FunCall("{}", Syntax.Braces);
call.getArgs().add(eNode);
eSet = call;
}
if (childExp == null) {
exp = eSet;
} else {
Exp childSet = bracesAround(childExp);
FunCall cj = new FunCall("CrossJoin", Syntax.Function);
cj.getArgs().add(eSet);
cj.getArgs().add(childSet);
if (exp == null) {
exp = cj;
} else {
FunCall call = new FunCall("Union", Syntax.Function);
call.getArgs().add(exp);
call.getArgs().add(cj);
exp = call;
}
}
}
return exp;
}
/**
* Generate MDX Expression
*
* @return
*/
public Exp generate() {
Exp exp = null;
List<TreeNode<Exp>> nodes = rootNode.getChildren();
// single members (nDimension = 1) are enclosed in set brackets
// collect single members
List<Exp> openSet = new ArrayList<Exp>();
// loop over top level nodes
for (TreeNode<Exp> node : nodes) {
Exp expForNode = genExpForNode(node, nDimension);
boolean closeOpenSet = false;
if (nDimension == 1) {
if (quaxUtil.isMember(expForNode)) {
openSet.add(expForNode);
continue;
} else {
closeOpenSet = true;
}
} else {
if (quaxUtil.isFunCallTo(expForNode, "()")) {
openSet.add(expForNode);
continue;
} else {
closeOpenSet = true;
}
}
if (closeOpenSet && !openSet.isEmpty()) {
// close open set
Exp set = new FunCall("{}", Syntax.Braces, openSet);
if (exp == null) {
exp = set;
} else {
// generate Union
FunCall call = new FunCall("Union", Syntax.Function);
call.getArgs().add(exp);
call.getArgs().add(set);
exp = call;
}
openSet.clear();
}
if (exp == null) {
exp = expForNode;
} else {
// generate Union of Exp and expForNode
FunCall call = new FunCall("Union", Syntax.Function);
call.getArgs().add(exp);
call.getArgs().add(expForNode);
exp = call;
}
}
if (!openSet.isEmpty()) {
// close open set
Exp set = new FunCall("{}", Syntax.Braces, openSet);
if (exp == null) {
exp = set;
} else {
// generate Union
FunCall call = new FunCall("Union", Syntax.Function);
call.getArgs().add(exp);
call.getArgs().add(set);
exp = call;
}
openSet.clear();
}
return exp;
}
