/**
* This method searches for an index word in a sentence tree
*
* @param wordToFind
* @param treeToSearch
* @param expectedPOS The expected POS tag for the result. If this is NULL, the method tries to
* find a phrase.
* @param canGoUp If TRUE the method will walk up the tree to find a phrase.
* @param skip Set to "1" if you want to find the phrase for "in front of". Set to "0" otherwise.
* @return The largest matching tree.
*/
public static Tree match(
IndexedWord wordToFind, Tree treeToSearch, String expectedPOS, boolean canGoUp, int skip) {
int end = wordToFind.get(EndIndexAnnotation.class);
int begin = wordToFind.get(BeginIndexAnnotation.class);
// first, find whatever is at the word's index
for (Tree tree : treeToSearch) {
CoreLabel lbl = ((CoreLabel) tree.label());
if (lbl != null
&& lbl.get(EndIndexAnnotation.class) != null
&& lbl.get(EndIndexAnnotation.class) == end) {
if (lbl.get(BeginIndexAnnotation.class) == begin) {
// we found the first subtree at the word's index
// now, check if the word here is our searchword
if (tree.getLeaves().get(0).label().value().equals(wordToFind.value())) {
// we have found the label.
Tree candidate = tree;
if (expectedPOS != null) {
// if we know our desired POS, just keep walking up the tree to find the first
// instance of the expected pos
while (!expectedPOS.equals(candidate.value())) {
// if we don't have the right POS, just try our parent
candidate = candidate.parent(treeToSearch);
if (candidate == null) {
return null;
}
}
candidate = skip(candidate, treeToSearch, expectedPOS, skip);
} else {
// else walk up the tree again to find the corresponding phrase
while (!candidate.isPhrasal()) {
candidate =
candidate.parent(treeToSearch); // edu.stanford.nlp.trees.Tree.parent(Tree root)
if (candidate == null) {
return null;
}
}
}
if (canGoUp) {
// now keep walking as long as the phrase does not change. this should yield the
// largest representative phrase for this word.
String phrase = candidate.value();
while (phrase.equals(candidate.parent(treeToSearch).value())) {
candidate = candidate.parent(treeToSearch);
if (candidate == null) {
return null;
}
}
}
return candidate;
}
}
}
}
return null;
}
