Class TreeNode

src/main/java/com/lodborg/intervaltree/TreeNode.java:72–511

A representation of a single node in the IntervalTree. Since the Interval Tree is practically a binary search tree, every node is identified by a unique key - the center (called middlepoint) of the first interval that triggers the creation of this node. The key is immutable and can't be

 * @param <T> The type for the start and end point of the interval
 */
public class TreeNode<T extends Comparable<? super T>> implements Iterable<Interval<T>> {
	/**
	 * A set containing all {@link Interval}s stored in this node, ordered by their
	 * starting points.
	 * @see Interval#sweepLeftToRight
	 */
	protected NavigableSet<Interval<T>> increasing;

	/**
	 * A set containing all {@link Interval}s stored in this node, ordered by their
	 * end points.
	 * @see Interval#sweepRightToLeft
	 */
	protected NavigableSet<Interval<T>> decreasing;

	/**
	 * A pointer to the left child of the current node. The left child must either be
	 * {@code null} or have a midpoint, smaller than the midpoint of the current node. More
	 * formally, {@code left.midpoint.compareTo(this.midpoint) < 0} must evaluate to {@code true}.
	 */
	protected TreeNode<T> left;

	/**
	 * A pointer to the right child of the current node. The right child must either be
	 * {@code null} or have a midpoint, larger than the midpoint of the current node. More
	 * formally, {@code right.midpoint.compareTo(this.midpoint) > 0} must evaluate to {@code true}.
	 */
	protected TreeNode<T> right;

	/**
	 * The midpoint of the initial interval added to the node. It is an immutable value
	 * and can not be changed, even if the initial interval has been removed from the
	 * node.
	 */
	protected final T midpoint;

	/**
	 * The height of the node.
	 */
	protected int height;

	/**
	 * Instantiates a new node in an {@link IntervalTree}.
	 *
	 * @param interval The initial interval stored in the node. The middlepoint of
	 *                 the node will be set based on this interval.
	 */
	public TreeNode(Interval<T> interval){
		decreasing = new TreeSet<>(Interval.sweepRightToLeft);
		increasing = new TreeSet<>(Interval.sweepLeftToRight);

		decreasing.add(interval);
		increasing.add(interval);
		midpoint = interval.getMidpoint();
		height = 1;
	}

	/**