protected void toStringWork(Object p, Object stop, StringBuffer buf) {
if (!adaptor.isNil(p)) {
String text = adaptor.getText(p);
if (text == null) {
text = " " + String.valueOf(adaptor.getType(p));
}
buf.append(text); // ask the node to go to string
}
if (p == stop) {
return;
}
int n = adaptor.getChildCount(p);
if (n > 0 && !adaptor.isNil(p)) {
buf.append(" ");
buf.append(Token.DOWN);
}
for (int c = 0; c < n; c++) {
Object child = adaptor.getChild(p, c);
toStringWork(child, stop, buf);
}
if (n > 0 && !adaptor.isNil(p)) {
buf.append(" ");
buf.append(Token.UP);
}
}
public boolean hasNext() {
if (firstTime) return root != null;
if (nodes != null && nodes.size() > 0) return true;
if (tree == null) return false;
if (adaptor.getChildCount(tree) > 0) return true;
return adaptor.getParent(tree) != null; // back at root?
}
/**
* Return the next node found during a depth-first walk of root. Also, add these nodes and DOWN/UP
* imaginary nodes into the lokoahead buffer as a side-effect. Normally side-effects are bad, but
* because we can emit many tokens for every next() call, it's pretty hard to use a single return
* value for that. We must add these tokens to the lookahead buffer.
*
* <p>This does *not* return the DOWN/UP nodes; those are only returned by the LT() method.
*
* <p>Ugh. This mechanism is much more complicated than a recursive solution, but it's the only
* way to provide nodes on-demand instead of walking once completely through and buffering up the
* nodes. :(
*/
public Object next() {
// already walked entire tree; nothing to return
if (currentNode == null) {
addLookahead(eof);
// this is infinite stream returning EOF at end forever
// so don't throw NoSuchElementException
return null;
}
// initial condition (first time method is called)
if (currentChildIndex == -1) {
return handleRootNode();
}
// index is in the child list?
if (currentChildIndex < adaptor.getChildCount(currentNode)) {
return visitChild(currentChildIndex);
}
// hit end of child list, return to parent node or its parent ...
walkBackToMostRecentNodeWithUnvisitedChildren();
if (currentNode != null) {
return visitChild(currentChildIndex);
}
return null;
}
protected void toDOTDefineEdges(Object tree, TreeAdaptor adaptor, StringTemplate treeST) {
if (tree == null) {
return;
}
int n = adaptor.getChildCount(tree);
if (n == 0) {
// must have already dumped as child from previous
// invocation; do nothing
return;
}
String parentName = "n" + getNodeNumber(tree);
// for each child, do a parent -> child edge using unique node names
String parentText = adaptor.getText(tree);
for (int i = 0; i < n; i++) {
Object child = adaptor.getChild(tree, i);
String childText = adaptor.getText(child);
String childName = "n" + getNodeNumber(child);
StringTemplate edgeST = _edgeST.getInstanceOf();
edgeST.setAttribute("parent", parentName);
edgeST.setAttribute("child", childName);
edgeST.setAttribute("parentText", fixString(parentText));
edgeST.setAttribute("childText", fixString(childText));
treeST.setAttribute("edges", edgeST);
toDOTDefineEdges(child, adaptor, treeST);
}
}
/** Walk upwards looking for a node with more children to walk. */
protected void walkBackToMostRecentNodeWithUnvisitedChildren() {
while (currentNode != null && currentChildIndex >= adaptor.getChildCount(currentNode)) {
currentNode = nodeStack.pop();
if (currentNode == null) { // hit the root?
return;
}
currentChildIndex = ((Integer) indexStack.pop()).intValue();
currentChildIndex++; // move to next child
if (currentChildIndex >= adaptor.getChildCount(currentNode)) {
if (!adaptor.isNil(currentNode)) {
addNavigationNode(Token.UP);
}
if (currentNode == root) { // we done yet?
currentNode = null;
}
}
}
}
public Object next() {
if (firstTime) { // initial condition
firstTime = false;
if (adaptor.getChildCount(tree) == 0) { // single node tree (special)
nodes.add(eof);
return tree;
}
return tree;
}
// if any queued up, use those first
if (nodes != null && nodes.size() > 0) return nodes.remove();
// no nodes left?
if (tree == null) return eof;
// next node will be child 0 if any children
if (adaptor.getChildCount(tree) > 0) {
tree = adaptor.getChild(tree, 0);
nodes.add(tree); // real node is next after DOWN
return down;
}
// if no children, look for next sibling of tree or ancestor
Object parent = adaptor.getParent(tree);
// while we're out of siblings, keep popping back up towards root
while (parent != null && adaptor.getChildIndex(tree) + 1 >= adaptor.getChildCount(parent)) {
nodes.add(up); // we're moving back up
tree = parent;
parent = adaptor.getParent(tree);
}
// no nodes left?
if (parent == null) {
tree = null; // back at root? nothing left then
nodes.add(eof); // add to queue, might have UP nodes in there
return nodes.remove();
}
// must have found a node with an unvisited sibling
// move to it and return it
int nextSiblingIndex = adaptor.getChildIndex(tree) + 1;
tree = adaptor.getChild(parent, nextSiblingIndex);
nodes.add(tree); // add to queue, might have UP nodes in there
return nodes.remove();
}
protected Object handleRootNode() {
Object node;
node = currentNode;
// point to first child in prep for subsequent next()
currentChildIndex = 0;
if (adaptor.isNil(node)) {
// don't count this root nil node
node = visitChild(currentChildIndex);
} else {
addLookahead(node);
if (adaptor.getChildCount(currentNode) == 0) {
// single node case
currentNode = null; // say we're done
}
}
return node;
}
protected void toDOTDefineNodes(Object tree, TreeAdaptor adaptor, StringTemplate treeST) {
if (tree == null) {
return;
}
int n = adaptor.getChildCount(tree);
if (n == 0) {
// must have already dumped as child from previous
// invocation; do nothing
return;
}
// define parent node
StringTemplate parentNodeST = getNodeST(adaptor, tree);
treeST.setAttribute("nodes", parentNodeST);
// for each child, do a "<unique-name> [label=text]" node def
for (int i = 0; i < n; i++) {
Object child = adaptor.getChild(tree, i);
StringTemplate nodeST = getNodeST(adaptor, child);
treeST.setAttribute("nodes", nodeST);
toDOTDefineNodes(child, adaptor, treeST);
}
}
