public static <A> void printTree(Tree<A> tree, PrintStream ps)
{
ps.printf("(%s (", tree.value());
for (Tree<A> t : tree.children())
{
printTree(t, ps);
ps.print(",");
}
ps.print("))");
}
// TODO all this is very memory inefficient and will lead to stack overflows for very deep trees
public static ObjectNode toJsonTree(ObjectMapper objectMapper, Tree<? extends JsonNode> tree)
{
final ObjectNode node = objectMapper.createObjectNode();
node.put("_value", tree.value());
final ArrayNode children = objectMapper.createArrayNode();
for (Tree<? extends JsonNode> child : tree.children())
children.add(toJsonTree(objectMapper, child));
node.put("_children", children);
return node;
}
/**
* Map a function over a tree
*
* @param fn Function
* @param tree Tree of {@code A}'s
* @return Tree of {@code B}'s
*/
public static <A,B> Tree<B> map(final Function<A,B> fn, Tree<A> tree)
{
final B value = fn.apply(tree.value());
if (isLeaf(tree))
return new ImmutableTree<B>(value);
else
{
final Function<Tree<A>,Tree<B>> tmap = new Function<Tree<A>,Tree<B>>()
{
public Tree<B> apply(Tree<A> tree)
{
return map(fn, tree);
}
};
final Iterable<Tree<B>> tb = Iterables.transform(tree.children(), tmap);
return new ImmutableTree<B>(value, tb);
}
}
public static final <_> boolean isLeaf(final Tree<_> tree)
{
return Iterables.isEmpty(tree.children());
}
