// determine if nodes are homogeneous, meaning their descendant structure is 'identical' for repeat purposes
// identical means all children match, and the children's children match, and so on
// repeatable children are ignored; as they do not have to exist in the same quantity for nodes to be homogeneous
// however, the child repeatable nodes MUST be verified amongst themselves for homogeneity later
// this function ignores the names of the two nodes
public static Boolean isHomogeneous(TreeElement a, TreeElement b)
{
if (a.isLeaf() && b.isLeaf())
{
return(true);
}
else if (a.isChildable() && b.isChildable())
{
// verify that every (non-repeatable) node in a exists in b and vice
// versa
for (int k = 0; k < 2; k++)
{
TreeElement n1 = (k == 0 ? a : b);
TreeElement n2 = (k == 0 ? b : a);
for (int i = 0; i < n1.getNumChildren(); i++)
{
TreeElement child1 = n1.getChildAt(i);
if (child1.repeatable)
{
continue;
}
TreeElement child2 = n2.getChild(child1.getName(), 0);
if (child2 == null)
{
return(false);
}
if (child2.repeatable)
{
throw new SystemException("shouldn't happen");
}
}
}
// compare children
for (int i = 0; i < a.getNumChildren(); i++)
{
TreeElement childA = a.getChildAt(i);
if (childA.repeatable)
{
continue;
}
TreeElement childB = b.getChild(childA.getName(), 0);
if (!isHomogeneous(childA, childB))
{
return(false);
}
}
return(true);
}
else
{
return(false);
}
}
// for making new repeat instances; 'from' and 'to' must be unambiguous
// references EXCEPT 'to' may be ambiguous at its final step
// return true is successfully copied, false otherwise
public TreeElement copyNode(TreeElement src, TreeReference to)
{
if (!to.isAbsolute())
{
throw new InvalidReferenceException("Destination reference must be absolute for copying", to);
}
// strip out dest node info and get dest parent
String dstName = to.getNameLast();
int dstMult = to.getMultLast();
TreeReference toParent = to.getParentRef();
TreeElement parent = resolveReference(toParent);
if (parent == null)
{
throw new InvalidReferenceException("Null parent reference whle attempting to copy", toParent);
}
if (!parent.isChildable())
{
throw new InvalidReferenceException("Invalid Parent Node: cannot accept children.", toParent);
}
if (dstMult == TreeReference.INDEX_UNBOUND)
{
dstMult = parent.getChildMultiplicity(dstName);
}
else if (parent.getChild(dstName, dstMult) != null)
{
throw new InvalidReferenceException("Destination already exists!", to);
}
TreeElement dest = src.deepCopy(false);
dest.setName(dstName);
dest.multiplicity = dstMult;
parent.addChild(dest);
return(dest);
}
/*
* create the specified node in the tree, creating all intermediary nodes at
* each step, if necessary. if specified node already exists, return null
*
* creating a duplicate node is only allowed at the final step. it will be
* done if the multiplicity of the last step is ALL or equal to the count of
* nodes already there
*
* at intermediate steps, the specified existing node is used; if
* multiplicity is ALL: if no nodes exist, a new one is created; if one node
* exists, it is used; if multiple nodes exist, it's an error
*
* return the newly-created node; modify ref so that it's an unambiguous ref
* to the node
*/
private TreeElement createNode(TreeReference ref_)
{
TreeElement node = root;
for (int k = 0; k < ref_.size(); k++)
{
String name = ref_.getName(k);
int count = node.getChildMultiplicity(name);
int mult = ref_.getMultiplicity(k);
TreeElement child;
if (k < ref_.size() - 1)
{
if (mult == TreeReference.INDEX_UNBOUND)
{
if (count > 1)
{
return(null); // don't know which node to use
}
else
{
// will use existing (if one and only one) or create new
mult = 0;
ref_.setMultiplicity(k, 0);
}
}
// fetch
child = node.getChild(name, mult);
if (child == null)
{
if (mult == 0)
{
// create
child = new TreeElement(name, count);
node.addChild(child);
ref_.setMultiplicity(k, count);
}
else
{
return(null); // intermediate node does not exist
}
}
}
else
{
if (mult == TreeReference.INDEX_UNBOUND || mult == count)
{
if (k == 0 && root.getNumChildren() != 0)
{
return(null); // can only be one top-level node, and it
// already exists
}
if (!node.isChildable())
{
return(null); // current node can't have children
}
// create new
child = new TreeElement(name, count);
node.addChild(child);
ref_.setMultiplicity(k, count);
}
else
{
return(null); // final node must be a newly-created node
}
}
node = child;
}
return(node);
}