Iterator class refactor

Set up GitHub Actions

.github/workflows/build.yml

@@ -0,0 +1,24 @@
+name: Build
+
+on: pull_request
+
+jobs:
+  build:
+    name: Check project build
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out code
+        uses: actions/checkout@v2
+      - name: Set up JDK 11
+        uses: actions/setup-java@v2
+        with:
+          distribution: adopt
+          java-version: 11
+
+        # Builds the release artifacts of the library
+      - name: Build
+        run: ./gradlew assemble
+
+        # Generates other artifacts (javadocJar is optional)
+      - name: Source jar and dokka
+        run: ./gradlew androidSourcesJar javadocJar

.github/workflows/test.yml

@@ -0,0 +1,23 @@
+name: Test
+
+on:
+  pull_request:
+    branches:
+      - master
+
+jobs:
+  build:
+    name: Run unit tests
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out code
+        uses: actions/checkout@v2
+      - name: Set up JDK 11
+        uses: actions/setup-java@v2
+        with:
+          distribution: adopt
+          java-version: 11
+
+        # Builds the release artifacts of the library
+      - name: Test
+        run: ./gradlew test

README.md

@@ -1,7 +1,7 @@
 # Tree (Data Structure)
 [![maven](https://img.shields.io/maven-central/v/com.github.adriankuta/tree-structure?style=plastic)](https://mvnrepository.com/artifact/com.github.adriankuta/tree-structure)
 [![License: MIT](https://img.shields.io/github/license/AdrianKuta/Tree-Data-Structure?style=plastic)](https://github.com/AdrianKuta/Design-Patterns-Kotlin/blob/master/LICENSE)
-[![CircleCI](https://img.shields.io/circleci/build/github/AdrianKuta/Tree-Data-Structure/master?label=CircleCI&style=plastic&logo=circleci)](https://circleci.com/gh/AdrianKuta/Tree-Data-Structure)
+[![Publish](https://github.com/AdrianKuta/Tree-Data-Structure/actions/workflows/publish.yml/badge.svg)](https://github.com/AdrianKuta/Tree-Data-Structure/actions/workflows/publish.yml)
 
 Simple implementation to store object in tree structure.
 

treedatastructure/build.gradle

@@ -13,7 +13,7 @@ android {
     defaultConfig {
         minSdkVersion 15
         targetSdkVersion 31
-        versionName "2.0.0"
+        versionName "2.0.3"
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
         consumerProguardFiles 'consumer-rules.pro'
     }

treedatastructure/src/main/java/com/github/adriankuta/datastructure/tree/PreOrderTreeIterator.kt

@@ -0,0 +1,42 @@
+package com.github.adriankuta.datastructure.tree
+
+import java.util.*
+
+/**
+ * Tree is iterated by using `Pre-order Traversal Algorithm"
+ *  1. Check if the current node is empty or null.
+ *  2. Display the data part of the root (or current node).
+ *  3. Traverse the left subtree by recursively calling the pre-order function.
+ *  4. Traverse the right subtree by recursively calling the pre-order function.
+ * ```
+ * E.g.
+ *                    1
+ *                  / | \
+ *                 /  |   \
+ *               2    3     4
+ *              / \       / | \
+ *             5    6    7  8  9
+ *            /   / | \
+ *           10  11 12 13
+ *
+ * Output: 1 2 5 10 6 11 12 13 3 4 7 8 9
+ * ```
+ */
+class PreOrderTreeIterator<T>(root: TreeNode<T>) : Iterator<TreeNode<T>> {
+
+    private val stack = Stack<TreeNode<T>>()
+
+    init {
+        stack.push(root)
+    }
+
+    override fun hasNext(): Boolean = !stack.empty()
+
+    override fun next(): TreeNode<T> {
+        val node = stack.pop()
+        node.children
+            .asReversed()
+            .forEach { stack.push(it) }
+        return node
+    }
+}

treedatastructure/src/main/java/com/github/adriankuta/datastructure/tree/TreeNode.kt

@@ -41,6 +41,7 @@ open class TreeNode<T>(val value: T) : Iterable<TreeNode<T>>, ChildDeclarationIn
      * @return `true` if the node has been successfully removed; `false` if it was not present in the tree.
      */
     fun removeChild(child: TreeNode<T>): Boolean {
+        println(child.value)
         val removed = child._parent?._children?.remove(child)
         child._parent = null
         return removed ?: false
@@ -136,5 +137,5 @@ open class TreeNode<T>(val value: T) : Iterable<TreeNode<T>>, ChildDeclarationIn
      * Output: 1 2 5 10 6 11 12 13 3 4 7 8 9
      * ```
      */
-    override fun iterator(): Iterator<TreeNode<T>> = TreeNodeIterator(this)
+    override fun iterator(): Iterator<TreeNode<T>> = PreOrderTreeIterator(this)
 }

treedatastructure/src/main/java/com/github/adriankuta/datastructure/tree/TreeNodeIterator.kt

@@ -1,22 +0,0 @@
-package com.github.adriankuta.datastructure.tree
-
-import java.util.*
-
-class TreeNodeIterator<T>(root: TreeNode<T>) : Iterator<TreeNode<T>> {
-
-    private val stack = Stack<TreeNode<T>>()
-
-    init {
-        stack.push(root)
-    }
-
-    override fun hasNext(): Boolean = !stack.empty()
-
-    override fun next(): TreeNode<T> {
-        val node = stack.pop()
-        node.children
-            .asReversed()
-            .forEach { stack.push(it) }
-        return node
-    }
-}

treedatastructure/src/test/java/com/github/adriankuta/datastructure/tree/TreeNodeTest.kt

@@ -43,7 +43,8 @@ class TreeNodeTest {
                     "│   └── Milk Shake\n" +
                     "└── Curd\n" +
                     "    ├── yogurt\n" +
-                    "    └── lassi\n", root.toString()
+                    "    └── lassi\n",
+            root.prettyString()
         )
 
         println("Remove: ${curdNode.value}")
@@ -56,7 +57,8 @@ class TreeNodeTest {
                     "    ├── tea\n" +
                     "    │   └── normal tea\n" +
                     "    ├── coffee\n" +
-                    "    └── Milk Shake\n", root.toString()
+                    "    └── Milk Shake\n",
+            root.prettyString()
         )
     }