package t234;

/**
* Represents the abstract state of a 2-3-4 tree.
* @since 11/13/01
* @author Dung X. Nguyen, Copyright 2001 - All Rights Reserved.
*/

abstract class ANode234 {
    /**
    * Checks the owner tree for emptiness.
    <pre>
    EXERCISE: Remove this isEmpty method and rewrite the insertion algorithm
    without checking for emptiness.
    </pre>
    */
    abstract boolean isEmpty (Tree234 owner);

    /**
    * Inserts an Integer into the owner without duplication.
    * @param owner the owner of this ANode234.
    * @param n != null Integer object to be inserted.
    */
    abstract void insert (Tree234 owner, Integer n);


    /**
    * Help insert an Integer into the owner, reconnecting the owner's parent
    * subtrees if needed.
    * Called from insert.
    * @param ownerPo the parent tree of the owner tree.
    * @param owner the owner of this ANode234.
    * @param n != null Integer object to be inserted.
    */
    abstract void insertHelper (Tree234 ownerPo, Tree234 owner, Integer n);

    /**
    * Adds a data element with its left and right subtrees to this ANode234
    * and re-attaches it to the owner tree.
    * @param owner the owner of this ANode234.
    * @param lTree a Tree234 whose elmements are less than n.
    * @param n != null Integer object to be inserted.
    * @param rTree a Tree234 whose elements are greater than n.
    */
    abstract void attach (Tree234 owner, Tree234 lTree, Integer n, Tree234 rTree);

    /**
     * Draws the root and subtrees at a given level >= 0.
     */
    abstract void drawRootAndSubtrees(int level);

    /**
     * Template method pattern: Invariant behavior.
     */
    final void drawAtLevel (int level) {
        drawSpaces(level);
        drawRootAndSubtrees(level);
    }

    /**
     * Invariant behavior
     */
    final void drawSpaces (int n) {
        for (int i = 0; i < n; i++) {
            System.out.print ("   ");
        }
    }
}