package edu.stanford.nlp.trees;
import edu.stanford.nlp.io.IOUtils;
import java.util.function.Function;
import edu.stanford.nlp.util.Generics;
import edu.stanford.nlp.util.MutableInteger;
import edu.stanford.nlp.util.StringUtils;
import edu.stanford.nlp.ling.*;
import java.util.*;
import java.io.*;
/**
* Various static utilities for the <code>Tree</code> class.
*
* @author Roger Levy
* @author Dan Klein
* @author Aria Haghighi (tree path methods)
*/
public class Trees {
private static final LabeledScoredTreeFactory defaultTreeFactory = new LabeledScoredTreeFactory();
private Trees() {}
/**
* Returns the positional index of the left edge of a tree <i>t</i>
* within a given root, as defined by the size of the yield of all
* material preceding <i>t</i>.
*/
public static int leftEdge(Tree t, Tree root) {
MutableInteger i = new MutableInteger(0);
if (leftEdge(t, root, i)) {
return i.intValue();
} else {
throw new RuntimeException("Tree is not a descendant of root.");
// return -1;
}
}
/**
* Returns the positional index of the left edge of a tree <i>t</i>
* within a given root, as defined by the size of the yield of all
* material preceding <i>t</i>.
* This method returns -1 if no path is found, rather than exceptioning.
*
* @see Trees#leftEdge(Tree, Tree)
*/
public static int leftEdgeUnsafe(Tree t, Tree root) {
MutableInteger i = new MutableInteger(0);
if (leftEdge(t, root, i)) {
return i.intValue();
} else {
return -1;
}
}
static boolean leftEdge(Tree t, Tree t1, MutableInteger i) {
if (t == t1) {
return true;
} else if (t1.isLeaf()) {
int j = t1.yield().size(); // so that empties don't add size
i.set(i.intValue() + j);
return false;
} else {
for (Tree kid : t1.children()) {
if (leftEdge(t, kid, i)) {
return true;
}
}
return false;
}
}
/**
* Returns the positional index of the right edge of a tree
* <i>t</i> within a given root, as defined by the size of the yield
* of all material preceding <i>t</i> plus all the material
* contained in <i>t</i>.
*/
public static int rightEdge(Tree t, Tree root) {
MutableInteger i = new MutableInteger(root.yield().size());
if (rightEdge(t, root, i)) {
return i.intValue();
} else {
throw new RuntimeException("Tree is not a descendant of root.");
// return root.yield().size() + 1;
}
}
/**
* Returns the positional index of the right edge of a tree
* <i>t</i> within a given root, as defined by the size of the yield
* of all material preceding <i>t</i> plus all the material
* contained in <i>t</i>.
* This method returns root.yield().size() + 1 if no path is found, rather than exceptioning.
*
* @see Trees#rightEdge(Tree, Tree)
*/
public static int rightEdgeUnsafe(Tree t, Tree root) {
MutableInteger i = new MutableInteger(root.yield().size());
if (rightEdge(t, root, i)) {
return i.intValue();
} else {
return root.yield().size() + 1;
}
}
static boolean rightEdge(Tree t, Tree t1, MutableInteger i) {
if (t == t1) {
return true;
} else if (t1.isLeaf()) {
int j = t1.yield().size(); // so that empties don't add size
i.set(i.intValue() - j);
return false;
} else {
Tree[] kids = t1.children();
for (int j = kids.length - 1; j >= 0; j--) {
if (rightEdge(t, kids[j], i)) {
return true;
}
}
return false;
}
}
/**
* Returns a lexicalized Tree whose Labels are CategoryWordTag
* instances, all corresponds to the input tree.
*/
public static Tree lexicalize(Tree t, HeadFinder hf) {
Function<Tree,Tree> a =
TreeFunctions.getLabeledTreeToCategoryWordTagTreeFunction();
Tree t1 = a.apply(t);
t1.percolateHeads(hf);
return t1;
}
/**
* returns the leaves in a Tree in the order that they're found.
*/
public static List<Tree> leaves(Tree t) {
List<Tree> l = new ArrayList<>();
leaves(t, l);
return l;
}
private static void leaves(Tree t, List<Tree> l) {
if (t.isLeaf()) {
l.add(t);
} else {
for (Tree kid : t.children()) {
leaves(kid, l);
}
}
}
public static List<Tree> preTerminals(Tree t) {
List<Tree> l = new ArrayList<>();
preTerminals(t, l);
return l;
}
private static void preTerminals(Tree t, List<Tree> l) {
if (t.isPreTerminal()) {
l.add(t);
} else {
for (Tree kid : t.children()) {
preTerminals(kid, l);
}
}
}
/**
* returns the labels of the leaves in a Tree in the order that they're found.
*/
public static List<Label> leafLabels(Tree t) {
List<Label> l = new ArrayList<>();
leafLabels(t, l);
return l;
}
private static void leafLabels(Tree t, List<Label> l) {
if (t.isLeaf()) {
l.add(t.label());
} else {
for (Tree kid : t.children()) {
leafLabels(kid, l);
}
}
}
/**
* returns the labels of the leaves in a Tree, augmented with POS tags. assumes that
* the labels are CoreLabels.
*/
public static List<CoreLabel> taggedLeafLabels(Tree t) {
List<CoreLabel> l = new ArrayList<>();
taggedLeafLabels(t, l);
return l;
}
private static void taggedLeafLabels(Tree t, List<CoreLabel> l) {
if (t.isPreTerminal()) {
CoreLabel fl = (CoreLabel)t.getChild(0).label();
fl.set(CoreAnnotations.TagLabelAnnotation.class, t.label());
l.add(fl);
} else {
for (Tree kid : t.children()) {
taggedLeafLabels(kid, l);
}
}
}
/**
* Given a tree, set the tags on the leaf nodes if they are not
* already set. Do this by using the preterminal's value as a tag.
*/
public static void setLeafTagsIfUnset(Tree tree) {
if (tree.isPreTerminal()) {
Tree leaf = tree.children()[0];
if (!(leaf.label() instanceof HasTag)) {
return;
}
HasTag label = (HasTag) leaf.label();
if (label.tag() == null) {
label.setTag(tree.value());
}
} else {
for (Tree child : tree.children()) {
setLeafTagsIfUnset(child);
}
}
}
/**
* Replace the labels of the leaves with the given leaves.
*/
public static void setLeafLabels(Tree tree, List<Label> labels) {
Iterator<Tree> leafIterator = tree.getLeaves().iterator();
Iterator<Label> labelIterator = labels.iterator();
while (leafIterator.hasNext() && labelIterator.hasNext()) {
Tree leaf = leafIterator.next();
Label label = labelIterator.next();
leaf.setLabel(label);
//leafIterator.next().setLabel(labelIterator.next());
}
if (leafIterator.hasNext()) {
throw new IllegalArgumentException("Tree had more leaves than the labels provided");
}
if (labelIterator.hasNext()) {
throw new IllegalArgumentException("More labels provided than tree had leaves");
}
}
/**
* returns the maximal projection of <code>head</code> in
* <code>root</code> given a {@link HeadFinder}
*/
public static Tree maximalProjection(Tree head, Tree root, HeadFinder hf) {
Tree projection = head;
if (projection == root) {
return root;
}
Tree parent = projection.parent(root);
while (hf.determineHead(parent) == projection) {
projection = parent;
if (projection == root) {
return root;
}
parent = projection.parent(root);
}
return projection;
}
/* applies a TreeVisitor to all projections (including the node itself) of a node in a Tree.
* Does nothing if head is not in root.
* @return the maximal projection of head in root.
*/
public static Tree applyToProjections(TreeVisitor v, Tree head, Tree root, HeadFinder hf) {
Tree projection = head;
Tree parent = projection.parent(root);
if (parent == null && projection != root) {
return null;
}
v.visitTree(projection);
if (projection == root) {
return root;
}
while (hf.determineHead(parent) == projection) {
projection = parent;
v.visitTree(projection);
if (projection == root) {
return root;
}
parent = projection.parent(root);
}
return projection;
}
/**
* gets the <code>n</code>th terminal in <code>tree</code>. The first terminal is number zero.
*/
public static Tree getTerminal(Tree tree, int n) {
return getTerminal(tree, new MutableInteger(0), n);
}
static Tree getTerminal(Tree tree, MutableInteger i, int n) {
if (i.intValue() == n) {
if (tree.isLeaf()) {
return tree;
} else {
return getTerminal(tree.children()[0], i, n);
}
} else {
if (tree.isLeaf()) {
i.set(i.intValue() + tree.yield().size());
return null;
} else {
for (Tree kid : tree.children()) {
Tree result = getTerminal(kid, i, n);
if (result != null) {
return result;
}
}
return null;
}
}
}
/**
* gets the <code>n</code>th preterminal in <code>tree</code>. The first terminal is number zero.
*/
public static Tree getPreTerminal(Tree tree, int n) {
return getPreTerminal(tree, new MutableInteger(0), n);
}
static Tree getPreTerminal(Tree tree, MutableInteger i, int n) {
if (i.intValue() == n) {
if (tree.isPreTerminal()) {
return tree;
} else {
return getPreTerminal(tree.children()[0], i, n);
}
} else {
if (tree.isPreTerminal()) {
i.set(i.intValue() + tree.yield().size());
return null;
} else {
for (Tree kid : tree.children()) {
Tree result = getPreTerminal(kid, i, n);
if (result != null) {
return result;
}
}
return null;
}
}
}
/**
* returns the syntactic category of the tree as a list of the syntactic categories of the mother and the daughters
*/
public static List<String> localTreeAsCatList(Tree t) {
List<String> l = new ArrayList<>(t.children().length + 1);
l.add(t.label().value());
for (int i = 0; i < t.children().length; i++) {
l.add(t.children()[i].label().value());
}
return l;
}
/**
* Returns the index of <code>daughter</code> in <code>parent</code> by ==.
* Returns -1 if <code>daughter</code> not found.
*/
public static int objectEqualityIndexOf(Tree parent, Tree daughter) {
for (int i = 0; i < parent.children().length; i++) {
if (daughter == parent.children()[i]) {
return i;
}
}
return -1;
}
/** Returns a String reporting what kinds of Tree and Label nodes this
* Tree contains.
*
* @param t The tree to examine.
* @return A human-readable String reporting what kinds of Tree and Label nodes this
* Tree contains.
*/
public static String toStructureDebugString(Tree t) {
String tCl = StringUtils.getShortClassName(t);
String tfCl = StringUtils.getShortClassName(t.treeFactory());
String lCl = StringUtils.getShortClassName(t.label());
String lfCl = StringUtils.getShortClassName(t.label().labelFactory());
Set<String> otherClasses = Generics.newHashSet();
String leafLabels = null;
String tagLabels = null;
String phraseLabels = null;
String leaves = null;
String nodes = null;
for (Tree st : t) {
String stCl = StringUtils.getShortClassName(st);
String stfCl = StringUtils.getShortClassName(st.treeFactory());
String slCl = StringUtils.getShortClassName(st.label());
String slfCl = StringUtils.getShortClassName(st.label().labelFactory());
if ( ! tCl.equals(stCl)) {
otherClasses.add(stCl);
}
if ( ! tfCl.equals(stfCl)) {
otherClasses.add(stfCl);
}
if ( ! lCl.equals(slCl)) {
otherClasses.add(slCl);
}
if ( ! lfCl.equals(slfCl)) {
otherClasses.add(slfCl);
}
if (st.isPhrasal()) {
if (nodes == null) {
nodes = stCl;
} else if ( ! nodes.equals(stCl)) {
nodes = "mixed";
}
if (phraseLabels == null) {
phraseLabels = slCl;
} else if ( ! phraseLabels.equals(slCl)) {
phraseLabels = "mixed";
}
} else if (st.isPreTerminal()) {
if (nodes == null) {
nodes = stCl;
} else if ( ! nodes.equals(stCl)) {
nodes = "mixed";
}
if (tagLabels == null) {
tagLabels = StringUtils.getShortClassName(slCl);
} else if ( ! tagLabels.equals(slCl)) {
tagLabels = "mixed";
}
} else if (st.isLeaf()) {
if (leaves == null) {
leaves = stCl;
} else if ( ! leaves.equals(stCl)) {
leaves = "mixed";
}
if (leafLabels == null) {
leafLabels = slCl;
} else if ( ! leafLabels.equals(slCl)) {
leafLabels = "mixed";
}
} else {
throw new IllegalStateException("Bad tree state: " + t);
}
} // end for Tree st : this
StringBuilder sb = new StringBuilder();
sb.append("Tree with root of class ").append(tCl).append(" and factory ").append(tfCl);
sb.append(" and root label class ").append(lCl).append(" and factory ").append(lfCl);
if ( ! otherClasses.isEmpty()) {
sb.append(" and the following classes also found within the tree: ").append(otherClasses);
return " with " + nodes + " interior nodes and " + leaves +
" leaves, and " + phraseLabels + " phrase labels, " +
tagLabels + " tag labels, and " + leafLabels + " leaf labels.";
} else {
sb.append(" (and uniform use of these Tree and Label classes throughout the tree).");
}
return sb.toString();
}
/** Turns a sentence into a flat phrasal tree.
* The structure is S -> tag*. And then each tag goes to a word.
* The tag is either found from the label or made "WD".
* The tag and phrasal node have a StringLabel.
*
* @param s The Sentence to make the Tree from
* @return The one phrasal level Tree
*/
public static Tree toFlatTree(List<HasWord> s) {
return toFlatTree(s, new StringLabelFactory());
}
/** Turns a sentence into a flat phrasal tree.
* The structure is S -> tag*. And then each tag goes to a word.
* The tag is either found from the label or made "WD".
* The tag and phrasal node have a StringLabel.
*
* @param s The Sentence to make the Tree from
* @param lf The LabelFactory with which to create the new Tree labels
* @return The one phrasal level Tree
*/
public static Tree toFlatTree(List<? extends HasWord> s, LabelFactory lf) {
List<Tree> daughters = new ArrayList<>(s.size());
for (HasWord word : s) {
Tree wordNode = new LabeledScoredTreeNode(lf.newLabel(word.word()));
if (word instanceof TaggedWord) {
TaggedWord taggedWord = (TaggedWord) word;
wordNode = new LabeledScoredTreeNode(new StringLabel(taggedWord.tag()), Collections.singletonList(wordNode));
} else {
wordNode = new LabeledScoredTreeNode(lf.newLabel("WD"), Collections.singletonList(wordNode));
}
daughters.add(wordNode);
}
return new LabeledScoredTreeNode(new StringLabel("S"), daughters);
}
public static String treeToLatex(Tree t) {
StringBuilder connections = new StringBuilder();
StringBuilder hierarchy = new StringBuilder();
treeToLatexHelper(t,connections,hierarchy,0,1,0);
return "\\tree"+hierarchy+ '\n' +connections+ '\n';
}
private static int treeToLatexHelper(Tree t, StringBuilder c, StringBuilder h,
int n, int nextN, int indent) {
StringBuilder sb = new StringBuilder();
for (int i=0; i<indent; i++)
sb.append(" ");
h.append('\n').append(sb);
h.append("{\\").append(t.isLeaf() ? "" : "n").append("tnode{z").append(n).append("}{").append(t.label()).append('}');
if (!t.isLeaf()) {
for (int k=0; k<t.children().length; k++) {
h.append(", ");
c.append("\\nodeconnect{z").append(n).append("}{z").append(nextN).append("}\n");
nextN = treeToLatexHelper(t.children()[k],c,h,nextN,nextN+1,indent+1);
}
}
h.append('}');
return nextN;
}
public static String treeToLatexEven(Tree t) {
StringBuilder connections = new StringBuilder();
StringBuilder hierarchy = new StringBuilder();
int maxDepth = t.depth();
treeToLatexEvenHelper(t,connections,hierarchy,0,1,0,0,maxDepth);
return "\\tree"+hierarchy+ '\n' +connections+ '\n';
}
private static int treeToLatexEvenHelper(Tree t, StringBuilder c, StringBuilder h, int n,
int nextN, int indent, int curDepth, int maxDepth) {
StringBuilder sb = new StringBuilder();
for (int i=0; i<indent; i++)
sb.append(" ");
h.append('\n').append(sb);
int tDepth = t.depth();
if (tDepth == 0 && tDepth+curDepth < maxDepth) {
for (int pad=0; pad < maxDepth-tDepth-curDepth; pad++) {
h.append("{\\ntnode{pad}{}, ");
}
}
h.append("{\\ntnode{z").append(n).append("}{").append(t.label()).append('}');
if (!t.isLeaf()) {
for (int k=0; k<t.children().length; k++) {
h.append(", ");
c.append("\\nodeconnect{z").append(n).append("}{z").append(nextN).append("}\n");
nextN = treeToLatexEvenHelper(t.children()[k],c,h,nextN,nextN+1,indent+1,curDepth+1,maxDepth);
}
}
if (tDepth == 0 && tDepth+curDepth < maxDepth) {
for (int pad=0; pad < maxDepth-tDepth-curDepth; pad++) {
h.append('}');
}
}
h.append('}');
return nextN;
}
static String texTree(Tree t) {
return treeToLatex(t);
}
static String escape(String s) {
StringBuilder sb = new StringBuilder();
for (int i=0; i<s.length(); i++) {
char c = s.charAt(i);
if (c == '^')
sb.append('\\');
sb.append(c);
if (c == '^')
sb.append("{}");
}
return sb.toString();
}
public static void main(String[] args) throws IOException {
int i = 0;
while (i < args.length) {
Tree tree = Tree.valueOf(args[i]);
if (tree == null) {
// maybe it was a filename
tree = Tree.valueOf(IOUtils.slurpFile(args[i]));
}
if (tree != null) {
System.out.println(escape(texTree(tree)));
}
i++;
}
if (i == 0) {
Tree tree = (new PennTreeReader(new BufferedReader(new
InputStreamReader(System.in)), new LabeledScoredTreeFactory(new
StringLabelFactory()))).readTree();
System.out.println(escape(texTree(tree)));
}
}
public static Tree normalizeTree(Tree tree, TreeNormalizer tn, TreeFactory tf) {
for (Tree node : tree) {
if (node.isLeaf()) {
node.label().setValue(tn.normalizeTerminal(node.label().value()));
} else {
node.label().setValue(tn.normalizeNonterminal(node.label().value()));
}
}
return tn.normalizeWholeTree(tree, tf);
}
/**
* Gets the <i>i</i>th leaf of a tree from the left.
* The leftmost leaf is numbered 0.
*
* @return The <i>i</i><sup>th</sup> leaf as a Tree, or <code>null</code>
* if there is no such leaf.
*/
public static Tree getLeaf(Tree tree, int i) {
int count = -1;
for (Tree next : tree) {
if (next.isLeaf()) {
count++;
}
if (count == i) {
return next;
}
}
return null;
}
/**
* Get lowest common ancestor of all the nodes in the list with the tree rooted at root
*/
public static Tree getLowestCommonAncestor(List<Tree> nodes, Tree root) {
List<List<Tree>> paths = new ArrayList<>();
int min = Integer.MAX_VALUE;
for (Tree t : nodes) {
List<Tree> path = pathFromRoot(t, root);
if (path == null) return null;
min = Math.min(min, path.size());
paths.add(path);
}
Tree commonAncestor = null;
for (int i = 0; i < min; ++i) {
Tree ancestor = paths.get(0).get(i);
boolean quit = false;
for (List<Tree> path : paths) {
if (!path.get(i).equals(ancestor)) {
quit = true;
break;
}
}
if (quit) break;
commonAncestor = ancestor;
}
return commonAncestor;
}
/**
* returns a list of categories that is the path from Tree from to Tree
* to within Tree root. If either from or to is not in root,
* returns null. Otherwise includes both from and to in the list.
*/
public static List<String> pathNodeToNode(Tree from, Tree to, Tree root) {
List<Tree> fromPath = pathFromRoot(from, root);
//System.out.println(treeListToCatList(fromPath));
if (fromPath == null)
return null;
List<Tree> toPath = pathFromRoot(to, root);
//System.out.println(treeListToCatList(toPath));
if (toPath == null)
return null;
//System.out.println(treeListToCatList(fromPath));
//System.out.println(treeListToCatList(toPath));
int last = 0;
int min = fromPath.size() <= toPath.size() ? fromPath.size() : toPath.size();
Tree lastNode = null;
// while((! (fromPath.isEmpty() || toPath.isEmpty())) && fromPath.get(0).equals(toPath.get(0))) {
// lastNode = (Tree) fromPath.remove(0);
// toPath.remove(0);
// }
while (last < min && fromPath.get(last).equals(toPath.get(last))) {
lastNode = fromPath.get(last);
last++;
}
//System.out.println(treeListToCatList(fromPath));
//System.out.println(treeListToCatList(toPath));
List<String> totalPath = new ArrayList<>();
for (int i = fromPath.size() - 1; i >= last; i--) {
Tree t = fromPath.get(i);
totalPath.add("up-" + t.label().value());
}
if (lastNode != null)
totalPath.add("up-" + lastNode.label().value());
for (Tree t: toPath)
totalPath.add("down-" + t.label().value());
// for(ListIterator i = fromPath.listIterator(fromPath.size()); i.hasPrevious(); ){
// Tree t = (Tree) i.previous();
// totalPath.add("up-" + t.label().value());
// }
// if(lastNode != null)
// totalPath.add("up-" + lastNode.label().value());
// for(ListIterator j = toPath.listIterator(); j.hasNext(); ){
// Tree t = (Tree) j.next();
// totalPath.add("down-" + t.label().value());
// }
return totalPath;
}
/**
* returns list of tree nodes to root from t. Includes root and
* t. Returns null if tree not found dominated by root
*/
public static List<Tree> pathFromRoot(Tree t, Tree root) {
if (t == root) {
//if (t.equals(root)) {
List<Tree> l = new ArrayList<>(1);
l.add(t);
return l;
} else if (root == null) {
return null;
}
return root.dominationPath(t);
}
/**
* replaces all instances (by ==) of node with node1. Doesn't affect
* the node t itself
*/
public static void replaceNode(Tree node, Tree node1, Tree t) {
if (t.isLeaf())
return;
Tree[] kids = t.children();
List<Tree> newKids = new ArrayList<>(kids.length);
for (Tree kid : kids) {
if (kid != node) {
newKids.add(kid);
replaceNode(node, node1, kid);
} else {
newKids.add(node1);
}
}
t.setChildren(newKids);
}
/**
* returns the node of a tree which represents the lowest common
* ancestor of nodes t1 and t2 dominated by root. If either t1 or
* or t2 is not dominated by root, returns null.
*/
public static Tree getLowestCommonAncestor(Tree t1, Tree t2, Tree root) {
List<Tree> t1Path = pathFromRoot(t1, root);
List<Tree> t2Path = pathFromRoot(t2, root);
if (t1Path == null || t2Path == null) return null;
int min = Math.min(t1Path.size(), t2Path.size());
Tree commonAncestor = null;
for (int i = 0; i < min && t1Path.get(i).equals(t2Path.get(i)); ++i) {
commonAncestor = t1Path.get(i);
}
return commonAncestor;
}
// todo [cdm 2015]: These next two methods duplicate the Tree.valueOf methods!
/**
* Simple tree reading utility method. Given a tree formatted as a PTB string, returns a Tree made by a specific TreeFactory.
*/
public static Tree readTree(String ptbTreeString, TreeFactory treeFactory) {
try {
PennTreeReader ptr = new PennTreeReader(new StringReader(ptbTreeString), treeFactory);
return ptr.readTree();
} catch (IOException ex) {
throw new RuntimeException(ex);
}
}
/**
* Simple tree reading utility method. Given a tree formatted as a PTB string, returns a Tree made by the default TreeFactory (LabeledScoredTreeFactory)
*/
public static Tree readTree(String str) {
return readTree(str, defaultTreeFactory);
}
/**
* Outputs the labels on the trees, not just the words.
*/
public static void outputTreeLabels(Tree tree) {
outputTreeLabels(tree, 0);
}
public static void outputTreeLabels(Tree tree, int depth) {
for (int i = 0; i < depth; ++i) {
System.out.print(" ");
}
System.out.println(tree.label());
for (Tree child : tree.children()) {
outputTreeLabels(child, depth + 1);
}
}
/**
* Converts the tree labels to CoreLabels.
* We need this because we store additional info in the CoreLabel, like token span.
* @param tree
*/
public static void convertToCoreLabels(Tree tree) {
Label l = tree.label();
if (!(l instanceof CoreLabel)) {
CoreLabel cl = new CoreLabel();
cl.setValue(l.value());
tree.setLabel(cl);
}
for (Tree kid : tree.children()) {
convertToCoreLabels(kid);
}
}
/**
* Set the sentence index of all the leaves in the tree
* (only works on CoreLabel)
*/
public static void setSentIndex(Tree tree, int sentIndex) {
List<Label> leaves = tree.yield();
for (Label leaf : leaves) {
if (!(leaf instanceof CoreLabel)) {
throw new IllegalArgumentException("Only works on CoreLabel");
}
((CoreLabel) leaf).setSentIndex(sentIndex);
}
}
}