carry the code from core-java to data-structures module

data-structures/src/main/java/com/baeldung/printbinarytree/BinaryTreeModel.java

@@ -0,0 +1,37 @@
+package com.baeldung.printbinarytree;
+
+public class BinaryTreeModel {
+
+    private Object value;
+    private BinaryTreeModel left;
+    private BinaryTreeModel right;
+
+    public BinaryTreeModel(Object value) {
+        this.value = value;
+    }
+
+    public Object getValue() {
+        return value;
+    }
+
+    public void setValue(Object value) {
+        this.value = value;
+    }
+
+    public BinaryTreeModel getLeft() {
+        return left;
+    }
+
+    public void setLeft(BinaryTreeModel left) {
+        this.left = left;
+    }
+
+    public BinaryTreeModel getRight() {
+        return right;
+    }
+
+    public void setRight(BinaryTreeModel right) {
+        this.right = right;
+    }
+
+}

data-structures/src/main/java/com/baeldung/printbinarytree/BinaryTreePrinter.java

@@ -0,0 +1,63 @@
+package com.baeldung.printbinarytree;
+
+import java.io.PrintStream;
+
+public class BinaryTreePrinter {
+
+    private BinaryTreeModel tree;
+
+    public BinaryTreePrinter(BinaryTreeModel tree) {
+        this.tree = tree;
+    }
+
+    private String traversePreOrder(BinaryTreeModel root) {
+
+        if (root == null) {
+            return "";
+        }
+
+        StringBuilder sb = new StringBuilder();
+        sb.append(root.getValue());
+
+        String pointerRight = "└──";
+        String pointerLeft = (root.getRight() != null) ? "├──" : "└──";
+
+        traverseNodes(sb, "", pointerLeft, root.getLeft(), root.getRight() != null);
+        traverseNodes(sb, "", pointerRight, root.getRight(), false);
+
+        return sb.toString();
+    }
+
+    private void traverseNodes(StringBuilder sb, String padding, String pointer, BinaryTreeModel node,
+        boolean hasRightSibling) {
+
+        if (node != null) {
+
+            sb.append("\n");
+            sb.append(padding);
+            sb.append(pointer);
+            sb.append(node.getValue());
+
+            StringBuilder paddingBuilder = new StringBuilder(padding);
+            if (hasRightSibling) {
+                paddingBuilder.append("│  ");
+            } else {
+                paddingBuilder.append("   ");
+            }
+
+            String paddingForBoth = paddingBuilder.toString();
+            String pointerRight = "└──";
+            String pointerLeft = (node.getRight() != null) ? "├──" : "└──";
+
+            traverseNodes(sb, paddingForBoth, pointerLeft, node.getLeft(), node.getRight() != null);
+            traverseNodes(sb, paddingForBoth, pointerRight, node.getRight(), false);
+
+        }
+
+    }
+
+    public void print(PrintStream os) {
+        os.print(traversePreOrder(tree));
+    }
+
+}