---

Tree.java

package gov.nasa.arc.ase.util;

//#ifdef JDK11

//#else JDK11
import java.util.Collection;
//#endif JDK11

/**
 * This class represents a tree.
 */
public class Tree {
  /**
   * The root of the tree.
   */
  private TreeNode root;

  /**
   * Creates a new tree with no nodes.
   */
  public Tree() {
    root = null;
  }  
  /**
   * Gets all the node equal to a given one.
   */
  public Collection get(TreeNode n) {
    return root.get(n);
  }  
  /**
   * Returns the root of the tree.
   */
  public TreeNode getRoot() {
    return root;
  }  
  /**
   * Sets a new root.
   */
  void setRoot(TreeNode r) {
    root = r;
  }  
  /**
   * Returns a string rapresentation of the tree.
   */
  public String toString() {
    if(root == null) return "-";

    return "\\" + root.toString("   ");
  }  
}

---