Binary tree preorder traversal java goody

workspaces/adventure-pack/goodies/java/src/traverse_pre_order/AP.java

@@ -0,0 +1,57 @@
+package traverse_pre_order;
+
+import iterable_stream.IterableStream;
+import java.util.NoSuchElementException;
+import java.util.Stack;
+import simple_iterator.SimpleIterator;
+
+public final class AP {
+
+  /**
+   * Get an {@link IterableStream iterable stream} of all the {@link TreeNode nodes} in the binary
+   * tree in pre-order.
+   * @param root Binary tree root {@link TreeNode node}.
+   * @return The {@link IterableStream iterable stream} in pre-order.
+   */
+  public static IterableStream<TreeNode> traversePreOrder(final TreeNode root) {
+    final var stack = new Stack<TreeNode>();
+    stack.push(root);
+
+    return IterableStream.from(
+      SimpleIterator.toIterator(() -> {
+        while (!stack.isEmpty()) {
+          var node = stack.pop();
+
+          if (node != null) {
+            stack.push(node.right);
+            stack.push(node.left);
+            return node;
+          }
+        }
+
+        throw new NoSuchElementException();
+      })
+    );
+  }
+}
+
+class TreeNode {
+
+  // Class representing a single node in the binary tree.
+
+  int val;
+  TreeNode left;
+  TreeNode right;
+
+  TreeNode() {}
+
+  TreeNode(int val) {
+    this.val = val;
+  }
+
+  TreeNode(int val, TreeNode left, TreeNode right) {
+    this.val = val;
+    this.left = left;
+    this.right = right;
+  }
+}

workspaces/adventure-pack/goodies/java/src/traverse_pre_order/goody.json

@@ -0,0 +1,3 @@
+{
+  "name": "traversePreOrder()"
+}

workspaces/adventure-pack/src/app/__tests__/__snapshots__/equip-test.ts.snap

@@ -873,6 +873,137 @@ final class AP {
 /////////////////////////// END ADVENTURE PACK CODE ////////////////////////////"
 `;
 
+exports[`App can equip single goody: Java traversePreOrder() 1`] = `
+"////////////////////////// BEGIN ADVENTURE PACK CODE ///////////////////////////
+// Adventure Pack commit fake-commit-hash
+// Running at: https://example.com/
+
+import java.lang.reflect.Method;
+import java.lang.reflect.Proxy;
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+import java.util.Spliterator;
+import java.util.Stack;
+import java.util.function.Consumer;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+
+interface IterableStream<T> extends Iterable<T>, Stream<T> {
+  @Override
+  public void forEach(Consumer<? super T> action);
+
+  @Override
+  public Spliterator<T> spliterator();
+
+  public static <T> IterableStream<T> from(final Iterable<T> iterable) {
+    return from(iterable.spliterator());
+  }
+
+  public static <T> IterableStream<T> from(final Iterator<T> iterator) {
+    return from(() -> iterator);
+  }
+
+  public static <T> IterableStream<T> from(final Spliterator<T> spliterator) {
+    return from(StreamSupport.stream(spliterator, false));
+  }
+
+  public static <T> IterableStream<T> from(final Stream<T> stream) {
+    @SuppressWarnings("unchecked")
+    var proxy = (IterableStream<T>) Proxy.newProxyInstance(
+      ClassLoader.getSystemClassLoader(),
+      new Class<?>[] { IterableStream.class },
+      (Object _proxy, Method method, Object[] args) ->
+        Stream.class.getMethod(
+            method.getName(),
+            method.getParameterTypes()
+          ).invoke(stream, args)
+    );
+    return proxy;
+  }
+}
+
+interface SimpleIterator<T> {
+  public T next();
+
+  static enum HasNextState {
+    TRUE,
+    FALSE,
+    UNKNOWN,
+  }
+
+  public static <T> Iterator<T> toIterator(final SimpleIterator<T> iterator) {
+    final HasNextState[] hasNextState = { HasNextState.UNKNOWN };
+    final Object[] elementReserve = { null };
+
+    return new Iterator<T>() {
+      public boolean hasNext() {
+        if (hasNextState[0] == HasNextState.UNKNOWN) {
+          try {
+            elementReserve[0] = iterator.next();
+            hasNextState[0] = HasNextState.TRUE;
+          } catch (NoSuchElementException e) {
+            hasNextState[0] = HasNextState.FALSE;
+          }
+        }
+
+        return hasNextState[0] == HasNextState.TRUE;
+      }
+
+      public T next() {
+        if (hasNextState[0] == HasNextState.TRUE) {
+          hasNextState[0] = HasNextState.UNKNOWN;
+
+          @SuppressWarnings("unchecked")
+          T element = (T) elementReserve[0];
+
+          elementReserve[0] = null;
+          return element;
+        }
+
+        if (hasNextState[0] == HasNextState.UNKNOWN) {
+          return iterator.next();
+        }
+
+        throw new NoSuchElementException();
+      }
+    };
+  }
+}
+
+final class AP {
+  private AP() {}
+
+  /**
+   * Get an {@link IterableStream iterable stream} of all the {@link TreeNode nodes} in the binary
+   * tree in pre-order.
+   * @param root Binary tree root {@link TreeNode node}.
+   * @return The {@link IterableStream iterable stream} in pre-order.
+   */
+  public static IterableStream<TreeNode> traversePreOrder(final TreeNode root) {
+    final var stack = new Stack<TreeNode>();
+    stack.push(root);
+
+    return IterableStream.from(
+      SimpleIterator.toIterator(() -> {
+        while (!stack.isEmpty()) {
+          var node = stack.pop();
+
+          if (node != null) {
+            stack.push(node.right);
+            stack.push(node.left);
+            return node;
+          }
+        }
+
+        throw new NoSuchElementException();
+      })
+    );
+  }
+}
+
+/////////////////////////// END ADVENTURE PACK CODE ////////////////////////////"
+`;
+
 exports[`App can equip single goody: JavaScript Array.prototype.slidingWindows 1`] = `
 "////////////////////////// BEGIN ADVENTURE PACK CODE ///////////////////////////
 // Adventure Pack commit fake-commit-hash

workspaces/adventure-pack/src/app/__tests__/__snapshots__/render-test.ts.snap

@@ -539,6 +539,47 @@ final class AP {
 }"
 `;
 
+exports[`App can render goody: Java traversePreOrder() 1`] = `
+"package traverse_pre_order;
+
+import iterable_stream.IterableStream;
+import simple_iterator.SimpleIterator;
+
+import java.util.NoSuchElementException;
+import java.util.Stack;
+
+final class AP {
+  private AP() {}
+
+  /**
+   * Get an {@link IterableStream iterable stream} of all the {@link TreeNode nodes} in the binary
+   * tree in pre-order.
+   * @param root Binary tree root {@link TreeNode node}.
+   * @return The {@link IterableStream iterable stream} in pre-order.
+   */
+  public static IterableStream<TreeNode> traversePreOrder(final TreeNode root) {
+    final var stack = new Stack<TreeNode>();
+    stack.push(root);
+
+    return IterableStream.from(
+      SimpleIterator.toIterator(() -> {
+        while (!stack.isEmpty()) {
+          var node = stack.pop();
+
+          if (node != null) {
+            stack.push(node.right);
+            stack.push(node.left);
+            return node;
+          }
+        }
+
+        throw new NoSuchElementException();
+      })
+    );
+  }
+}"
+`;
+
 exports[`App can render goody: JavaScript Array.prototype.slidingWindows 1`] = `
 "import "ArraySlice";