public ParseNode addChild(String newlabel) {
ParseNode child = new ParseNode(newlabel, -1);
children.addElement(child);
child.setParent(this);
return child;
}
public ParseNode addChild(ParseNode child) {
if (child == null) throw new NullPointerException("Can't add null node to parse tree");
children.addElement(child);
child.setParent(this);
return child;
}
public ParseNode insertChild(ParseNode child) {
if (child == null) {
throw new NullPointerException("Can't add null node to parse tree");
}
children.insertElementAt(child, 0);
child.setParent(this);
return child;
}