Tree prune(Tree tree, int start) {
if (tree.isLeaf() || tree.isPreTerminal()) {
return tree;
}
// check each node's children for deletion
List<Tree> children = helper(tree.getChildrenAsList(), start);
children = prune(children, tree.label(), start, start + tree.yield().size());
return tree.treeFactory().newTreeNode(tree.label(), children);
}
public static Tree untransformTree(Tree tree) {
TreeFactory tf = tree.treeFactory();
if (tree.isPrePreTerminal()) {
if (tree.firstChild().label().value().matches(".*_.")) {
StringBuilder word = new StringBuilder();
for (int i = 0; i < tree.children().length; i++) {
Tree child = tree.children()[i];
word.append(child.firstChild().label().value());
}
Tree newChild = tf.newLeaf(word.toString());
tree.setChildren(Collections.singletonList(newChild));
}
} else {
for (int i = 0; i < tree.children().length; i++) {
Tree child = tree.children()[i];
untransformTree(child);
}
}
return tree;
}
public Tree transformTree(Tree tree) {
TreeFactory tf = tree.treeFactory();
String tag = tree.label().value();
if (tree.isPreTerminal()) {
String word = tree.firstChild().label().value();
List<Tree> newPreterms = new ArrayList<>();
for (int i = 0, size = word.length(); i < size; i++) {
String singleCharLabel = new String(new char[] {word.charAt(i)});
Tree newLeaf = tf.newLeaf(singleCharLabel);
String suffix;
if (useTwoCharTags) {
if (word.length() == 1 || i == 0) {
suffix = "_S";
} else {
suffix = "_M";
}
} else {
if (word.length() == 1) {
suffix = "_S";
} else if (i == 0) {
suffix = "_B";
} else if (i == word.length() - 1) {
suffix = "_E";
} else {
suffix = "_M";
}
}
newPreterms.add(tf.newTreeNode(tag + suffix, Collections.<Tree>singletonList(newLeaf)));
}
return tf.newTreeNode(tag, newPreterms);
} else {
List<Tree> newChildren = new ArrayList<>();
for (int i = 0; i < tree.children().length; i++) {
Tree child = tree.children()[i];
newChildren.add(transformTree(child));
}
return tf.newTreeNode(tag, newChildren);
}
}