Cleaned up the creator code in the tree classes, less branching is more better

Author: Justin Wetherell

src/com/jwetherell/algorithms/data_structures/AVLTree.java

@@ -17,7 +17,7 @@
  * 
  * @author Justin Wetherell <[email protected]>
  */
-public class AVLTree<T extends Comparable<T>> extends BinarySearchTree<T> implements BinarySearchTree.INodeCreator<T> {
+public class AVLTree<T extends Comparable<T>> extends BinarySearchTree<T> {
 
     private enum Balance {
         LEFT_LEFT, LEFT_RIGHT, RIGHT_LEFT, RIGHT_RIGHT
@@ -27,7 +27,15 @@ private enum Balance {
      * Default constructor.
      */
     public AVLTree() {
-        this.creator = this;
+        this.creator = new BinarySearchTree.INodeCreator<T>() {
+            /**
+             * {@inheritDoc}
+             */
+            @Override
+            public BinarySearchTree.Node<T> createNewNode(BinarySearchTree.Node<T> parent, T id) {
+                return (new AVLNode<T>(parent, id));
+            }
+        };
     }
 
     /**
@@ -245,14 +253,6 @@ public String toString() {
         return AVLTreePrinter.getString(this);
     }
 
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public Node<T> createNewNode(Node<T> parent, T id) {
-        return (new AVLNode<T>(parent, id));
-    }
-
     protected static class AVLNode<T extends Comparable<T>> extends Node<T> {
 
         protected int height = 1;

src/com/jwetherell/algorithms/data_structures/BinarySearchTree.java

@@ -45,7 +45,17 @@ public enum DepthFirstSearchOrder {
     /**
      * Default constructor.
      */
-    public BinarySearchTree() { }
+    public BinarySearchTree() {
+        this.creator = new INodeCreator<T>() {
+            /**
+             * {@inheritDoc}
+             */
+            @Override
+            public Node<T> createNewNode(Node<T> parent, T id) {
+                return (new Node<T>(parent, id));
+            }
+        };
+    }
 
     /**
      * Constructor with external Node creator.
@@ -72,11 +82,7 @@ public boolean add(T value) {
      * @return Node<T> which was added to the tree.
      */
     protected Node<T> addValue(T value) {
-        Node<T> newNode = null;
-        if (this.creator == null)
-            newNode = new Node<T>(null, value);
-        else
-            newNode = this.creator.createNewNode(null, value);
+        Node<T> newNode = this.creator.createNewNode(null, value);
 
         // If root is null, assign
         if (root == null) {

src/com/jwetherell/algorithms/data_structures/PatriciaTrie.java

@@ -24,7 +24,17 @@ public class PatriciaTrie<C extends CharSequence> implements ITree<C> {
     protected static final boolean BLACK = false; // non-terminating
     protected static final boolean WHITE = true; // terminating
 
-    public PatriciaTrie() { }
+    public PatriciaTrie() { 
+        this.creator = new INodeCreator() {
+            /**
+             * {@inheritDoc}
+             */
+            @Override
+            public Node createNewNode(Node parent, char[] seq, boolean type) {
+                return (new Node(parent, seq, type));
+            }
+        };
+    }
 
     /**
      * Constructor with external Node creator.
@@ -33,21 +43,6 @@ public PatriciaTrie(INodeCreator creator) {
         this.creator = creator;
     }
 
-    /**
-     * Create a new node for sequence.
-     * 
-     * @param parent
-     *            node of the new node.
-     * @param seq
-     *            of characters which represents this node.
-     * @param type
-     *            of the node, can be either BLACK or WHITE.
-     * @return Node which was created.
-     */
-    protected static Node createNewNode(Node parent, char[] seq, boolean type) {
-        return (new Node(parent, seq, type));
-    }
-
     /**
      * {@inheritDoc}
      */
@@ -67,12 +62,8 @@ public boolean add(C seq) {
      *         sequence already exists.
      */
     protected Node addSequence(C seq) {
-        if (root == null) {
-            if (this.creator == null)
-                root = createNewNode(null, null, BLACK);
-            else
-                root = this.creator.createNewNode(null, null, BLACK);
-        }
+        if (root == null)
+            root = this.creator.createNewNode(null, null, BLACK);
 
         int indexIntoParent = -1;
         int indexIntoString = -1;
@@ -117,11 +108,7 @@ protected Node addSequence(C seq) {
 
                 // Create new parent
                 if (parent != null) parent.removeChild(node);
-                Node newParent = null;
-                if (this.creator == null)
-                    newParent = createNewNode(parent, parentString, BLACK);
-                else
-                    newParent = this.creator.createNewNode(parent, parentString, BLACK);
+                Node newParent = this.creator.createNewNode(parent, parentString, BLACK);
                 if (parent != null)
                     parent.addChild(newParent);
 
@@ -133,11 +120,7 @@ protected Node addSequence(C seq) {
 
                 // Create a new node from the rest of the string
                 CharSequence newString = seq.subSequence(indexIntoString, seq.length());
-                Node newNode2 = null;
-                if (this.creator == null)
-                    newNode2 = createNewNode(newParent, newString.toString().toCharArray(), WHITE);
-                else
-                    newNode2 = this.creator.createNewNode(newParent, newString.toString().toCharArray(), WHITE);
+                Node newNode2 = this.creator.createNewNode(newParent, newString.toString().toCharArray(), WHITE);
                 newParent.addChild(newNode2);
 
                 // New node which was added
@@ -147,11 +130,7 @@ protected Node addSequence(C seq) {
                 // converting the previous node
                 if (parent != null)
                     parent.removeChild(node);
-                Node newParent = null;
-                if (this.creator == null)
-                    newParent = createNewNode(parent, parentString, WHITE);
-                else
-                    newParent = this.creator.createNewNode(parent, parentString, WHITE);
+                Node newParent = this.creator.createNewNode(parent, parentString, WHITE);
                 if (parent != null)
                     parent.addChild(newParent);
 
@@ -177,20 +156,12 @@ protected Node addSequence(C seq) {
         } else if (node.string != null) {
             // Adding a child
             CharSequence newString = seq.subSequence(indexIntoString, seq.length());
-            Node newNode = null;
-            if (this.creator == null)
-                newNode = createNewNode(node, newString.toString().toCharArray(), WHITE);
-            else
-                newNode = this.creator.createNewNode(node, newString.toString().toCharArray(), WHITE);
+            Node newNode = this.creator.createNewNode(node, newString.toString().toCharArray(), WHITE);
             node.addChild(newNode);
             addedNode = newNode;
         } else {
             // Add to root node
-            Node newNode = null;
-            if (this.creator == null)
-                newNode = createNewNode(node, seq.toString().toCharArray(), WHITE);
-            else
-                newNode = this.creator.createNewNode(node, seq.toString().toCharArray(), WHITE);
+            Node newNode = this.creator.createNewNode(node, seq.toString().toCharArray(), WHITE);
             node.addChild(newNode);
             addedNode = newNode;
         }

src/com/jwetherell/algorithms/data_structures/RedBlackTree.java

@@ -20,7 +20,7 @@
  * @author Justin Wetherell <[email protected]>
  */
 @SuppressWarnings("unchecked")
-public class RedBlackTree<T extends Comparable<T>> extends BinarySearchTree<T> implements BinarySearchTree.INodeCreator<T> {
+public class RedBlackTree<T extends Comparable<T>> extends BinarySearchTree<T> {
 
     protected static final boolean BLACK = false;
     protected static final boolean RED = true;
@@ -29,7 +29,15 @@ public class RedBlackTree<T extends Comparable<T>> extends BinarySearchTree<T> i
      * Default constructor.
      */
     public RedBlackTree() {
-        this.creator = this;
+        this.creator = new BinarySearchTree.INodeCreator<T>() {
+            /**
+             * {@inheritDoc}
+             */
+            @Override
+            public BinarySearchTree.Node<T> createNewNode(BinarySearchTree.Node<T> parent, T id) {
+                return (new RedBlackNode<T>(parent, id, BLACK));
+            }
+        };
     }
 
     /**
@@ -48,18 +56,12 @@ protected Node<T> addValue(T id) {
         boolean added = false;
         if (root == null) {
             // Case 1 - The current node is at the root of the tree.
-            if (this.creator == null) {
-                root = new RedBlackNode<T>(null, id, BLACK);
-                root.lesser = new RedBlackNode<T>(root, null, BLACK);
-                root.greater = new RedBlackNode<T>(root, null, BLACK);
-            } else {
-                root = this.creator.createNewNode(null, id);
-                ((RedBlackNode<T>) root).color = BLACK;
-                root.lesser = this.creator.createNewNode(root, null);
-                ((RedBlackNode<T>) root.lesser).color = BLACK;
-                root.greater = this.creator.createNewNode(root, null);
-                ((RedBlackNode<T>) root.greater).color = BLACK;
-            }
+
+            // Defaulted to black in our creator
+            root = this.creator.createNewNode(null, id);
+            root.lesser = this.creator.createNewNode(root, null);
+            root.greater = this.creator.createNewNode(root, null);
+
             nodeAdded = (RedBlackNode<T>) root;
             added = true;
         } else {
@@ -69,15 +71,11 @@ protected Node<T> addValue(T id) {
                 if (node.id == null) {
                     node.id = id;
                     ((RedBlackNode<T>) node).color = RED;
-                    if (this.creator == null) {
-                        node.lesser = new RedBlackNode<T>(node, null, BLACK);
-                        node.greater = new RedBlackNode<T>(node, null, BLACK);
-                    } else {
-                        node.lesser = this.creator.createNewNode(node, null);
-                        ((RedBlackNode<T>) node.lesser).color = BLACK;
-                        node.greater = this.creator.createNewNode(node, null);
-                        ((RedBlackNode<T>) node.greater).color = BLACK;
-                    }
+
+                    // Defaulted to black in our creator
+                    node.lesser = this.creator.createNewNode(node, null);
+                    node.greater = this.creator.createNewNode(node, null);
+
                     nodeAdded = (RedBlackNode<T>) node;
                     added = true;
                     break;
@@ -437,14 +435,6 @@ public String toString() {
         return RedBlackTreePrinter.getString(this);
     }
 
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public Node<T> createNewNode(Node<T> parent, T id) {
-        return (new RedBlackNode<T>(parent, id, BLACK));
-    }
-
     protected static class RedBlackNode<T extends Comparable<T>> extends Node<T> {
 
         protected boolean color = BLACK;

src/com/jwetherell/algorithms/data_structures/Treap.java

@@ -17,15 +17,23 @@
  * 
  * @author Justin Wetherell <[email protected]>
  */
-public class Treap<T extends Comparable<T>> extends BinarySearchTree<T> implements BinarySearchTree.INodeCreator<T> {
+public class Treap<T extends Comparable<T>> extends BinarySearchTree<T> {
 
     private static int randomSeed = Integer.MAX_VALUE; // This should be at least twice the number of Nodes
 
     /**
      * Default constructor.
      */
     public Treap() {
-        this.creator = this;
+        this.creator = new BinarySearchTree.INodeCreator<T>() {
+            /**
+             * {@inheritDoc}
+             */
+            @Override
+            public BinarySearchTree.Node<T> createNewNode(BinarySearchTree.Node<T> parent, T id) {
+                return (new TreapNode<T>(parent, id));
+            }
+        };
     }
 
     /**
@@ -143,24 +151,16 @@ public String toString() {
         return TreapPrinter.getString(this);
     }
 
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public Node<T> createNewNode(Node<T> parent, T id) {
-        return (new TreapNode<T>(null, id));
-    }
-
     private static class TreapNode<T extends Comparable<T>> extends Node<T> {
 
         private int priority = Integer.MIN_VALUE;
 
-        private TreapNode(TreapNode<T> parent, int priority, T value) {
+        private TreapNode(Node<T> parent, int priority, T value) {
             super(parent, value);
             this.priority = priority;
         }
 
-        private TreapNode(TreapNode<T> parent, T value) {
+        private TreapNode(Node<T> parent, T value) {
             this(parent, RANDOM.nextInt(randomSeed), value);
         }
 

src/com/jwetherell/algorithms/data_structures/TreeMap.java

@@ -3,6 +3,7 @@
 import java.util.ArrayList;
 import java.util.List;
 
+import com.jwetherell.algorithms.data_structures.BinarySearchTree.INodeCreator;
 import com.jwetherell.algorithms.data_structures.BinarySearchTree.Node;
 import com.jwetherell.algorithms.data_structures.interfaces.IMap;
 
@@ -18,12 +19,28 @@
  * @author Justin Wetherell <[email protected]>
  */
 @SuppressWarnings("unchecked")
-public class TreeMap<K extends Comparable<K>, V> implements BinarySearchTree.INodeCreator<K>, IMap<K,V> {
+public class TreeMap<K extends Comparable<K>, V> implements IMap<K,V> {
 
     private AVLTree<K> tree = null;
 
     public TreeMap() {
-        tree = new AVLTree<K>(this);
+        BinarySearchTree.INodeCreator<K> creator = new BinarySearchTree.INodeCreator<K>() {
+            /**
+             * {@inheritDoc}
+             */
+            @Override
+            public BinarySearchTree.Node<K> createNewNode(BinarySearchTree.Node<K> parent, K id) {
+                return (new TreeMapNode<K, V>(parent, id, null));
+            }
+        };
+        tree = new AVLTree<K>(creator);
+    }
+
+    /**
+     * Constructor with external Node creator.
+     */
+    public TreeMap(INodeCreator<K> creator) {
+        tree = new AVLTree<K>(creator);
     }
 
     /**
@@ -137,14 +154,6 @@ public String toString() {
         return TreeMapPrinter.getString(this);
     }
 
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public AVLTree.Node<K> createNewNode(AVLTree.Node<K> parent, K id) {
-        return (new TreeMapNode<K, V>(parent, id, null));
-    }
-
     protected static class TreeMapNode<K extends Comparable<K>, V> extends AVLTree.AVLNode<K> {
 
         protected V value = null;