java.lang.Object

cloud.opencode.base.tree.TreeTraverser

public final class TreeTraverser extends Object

Tree Traverser - Advanced tree traversal utilities 树遍历器 - 高级树遍历工具

Provides comprehensive traversal operations including controlled traversal, transformation, reduction, and stream-based operations.

提供全面的遍历操作，包括受控遍历、转换、归约和基于流的操作。

Features | 主要功能:

Controlled traversal (skip, stop) - 受控遍历（跳过、停止）
Parallel traversal - 并行遍历
Stream-based operations - 基于流的操作
Transform/reduce operations - 转换/归约操作
Iterator support - 迭代器支持
Ancestor/descendant queries - 祖先/后代查询

Usage Examples | 使用示例:

// Stream all nodes - 流式处理所有节点
TreeTraverser.stream(root)
    .filter(node -> node.getData() != null)
    .forEach(System.out::println);

// Controlled traversal - 受控遍历
TreeTraverser.traverse(root, node -> {
    if (shouldSkip(node)) return TraversalControl.SKIP_SUBTREE;
    if (shouldStop(node)) return TraversalControl.STOP;
    return TraversalControl.CONTINUE;
});

// Transform tree - 转换树
TreeNode<String> transformed = TreeTraverser.map(root, node -> node.toString());

// Reduce tree - 归约树
int sum = TreeTraverser.reduce(root, 0, (acc, node) -> acc + node.getValue());

Security | 安全性:

Thread-safe: Yes (stateless utility class) - 线程安全: 是（无状态工具类）
Null-safe: No (null root will cause NullPointerException) - 空值安全: 否（null根节点会导致空指针异常）

Since:

JDK 25, opencode-base-tree V1.0.0

Author:

Leon Soo www.LeonSoo.com

See Also:

Nested Class Summary

Nested Classes

Modifier and Type

Class

Description

static interface

TreeTraverser.ControlledVisitor<T>

Controlled traversal visitor 受控遍历访问者

static enum

TreeTraverser.TraversalControl

Traversal control enum 遍历控制枚举
Method Summary

Modifier and Type

Method

Description

static <T> Iterator<TreeNode<T>>

breadthFirstIterator(TreeNode<T> root)

Creates a breadth-first iterator 创建广度优先迭代器

static <T> Stream<TreeNode<T>>

breadthFirstStream(TreeNode<T> root)

Creates a breadth-first stream 创建广度优先流

static <T> TreeNode<T>

findLowestCommonAncestor(TreeNode<T> node1, TreeNode<T> node2)

Finds lowest common ancestor 查找最近公共祖先

static <T,R> Stream<R>

flatMap(TreeNode<T> root, Function<TreeNode<T>, Stream<R>> mapper)

Flat maps tree to stream 扁平映射树到流

static <T,R> R

foldBottomUp(TreeNode<T> root, Function<T,R> leafMapper, BiFunction<T,List<R>,R> branchFolder)

Folds tree bottom-up 自底向上折叠树

static <T> List<TreeNode<T>>

getAncestors(TreeNode<T> node)

Gets ancestors from parent to root 获取从父节点到根节点的祖先

static <T> int

getDepth(TreeNode<T> node)

Gets the depth of a node 获取节点深度

static <T> List<TreeNode<T>>

getDescendants(TreeNode<T> node)

Gets all descendants 获取所有后代

static <T> List<TreeNode<T>>

getSiblings(TreeNode<T> node)

Gets all siblings 获取所有兄弟节点

static <T,R> TreeNode<R>

map(TreeNode<T> root, Function<T,R> mapper)

Maps tree to new data type 将树映射到新数据类型

static <T,R> TreeNode<R>

mapNode(TreeNode<T> root, Function<TreeNode<T>, R> mapper)

Maps tree with node context 带节点上下文的树映射

static <T> Stream<TreeNode<T>>

parallelStream(TreeNode<T> root)

Creates a parallel stream 创建并行流

static <T> Iterator<TreeNode<T>>

postOrderIterator(TreeNode<T> root)

Creates a post-order iterator 创建后序迭代器

static <T> Stream<TreeNode<T>>

postOrderStream(TreeNode<T> root)

Creates a post-order stream 创建后序流

static <T> Iterator<TreeNode<T>>

preOrderIterator(TreeNode<T> root)

Creates a pre-order iterator 创建前序迭代器

static <T extends Treeable<T,ID>, ID> Iterator<T>

preOrderIterator(List<T> roots)

Creates a pre-order iterator for Treeable 创建Treeable的前序迭代器

static <T,R> R

reduce(TreeNode<T> root, R identity, BiFunction<R,T,R> accumulator)

Reduces tree to single value 将树归约为单个值

static <T,R> R

reduce(TreeNode<T> root, R identity, BiFunction<R,T,R> accumulator, BinaryOperator<R> combiner)

Reduces tree with combiner (for parallel) 带组合器的树归约（用于并行）

static <T> Stream<TreeNode<T>>

stream(TreeNode<T> root)

Creates a pre-order stream of TreeNode 创建TreeNode的前序流

static <T extends Treeable<T,ID>, ID> Stream<T>

stream(List<T> roots)

Creates a pre-order stream of Treeable nodes 创建Treeable节点的前序流

static <T> boolean

traverse(TreeNode<T> root, TreeTraverser.ControlledVisitor<T> visitor)

Traverses tree with control 带控制的树遍历

static <T extends Treeable<T,ID>, ID> boolean

traverse(List<T> roots, Function<T, TreeTraverser.TraversalControl> visitor)

Traverses Treeable nodes with control 带控制的Treeable节点遍历

Methods inherited from class Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details
- traverse
  
  public static <T> boolean traverse(TreeNode<T> root, TreeTraverser.ControlledVisitor<T> visitor)
  
  Traverses tree with control 带控制的树遍历
  
  Type Parameters:
  
  T - data type | 数据类型
  
  Parameters:
  
  root - root node | 根节点
  
  visitor - visitor with control | 带控制的访问者
  
  Returns:
  
  true if completed without stop | 如果完成且未停止则为true
- traverse
  
  public static <T extends Treeable<T,ID>, ID> boolean traverse(List<T> roots, Function<T, TreeTraverser.TraversalControl> visitor)
  
  Traverses Treeable nodes with control 带控制的Treeable节点遍历
  
  Type Parameters:
  
  T - node type | 节点类型
  
  ID - ID type | ID类型
  
  Parameters:
  
  roots - root nodes | 根节点列表
  
  visitor - visitor with control | 带控制的访问者
  
  Returns:
  
  true if completed without stop | 如果完成且未停止则为true
- stream
  
  public static <T> Stream<TreeNode<T>> stream(TreeNode<T> root)
  
  Creates a pre-order stream of TreeNode 创建TreeNode的前序流
  
  Type Parameters:
  
  T - data type | 数据类型
  
  Parameters:
  
  root - root node | 根节点
  
  Returns:
  
  stream of nodes | 节点流
- stream
  
  public static <T extends Treeable<T,ID>, ID> Stream<T> stream(List<T> roots)
  
  Creates a pre-order stream of Treeable nodes 创建Treeable节点的前序流
  
  Type Parameters:
  
  T - node type | 节点类型
  
  ID - ID type | ID类型
  
  Parameters:
  
  roots - root nodes | 根节点列表
  
  Returns:
  
  stream of nodes | 节点流
- parallelStream
  
  public static <T> Stream<TreeNode<T>> parallelStream(TreeNode<T> root)
  
  Creates a parallel stream 创建并行流
  
  Type Parameters:
  
  T - data type | 数据类型
  
  Parameters:
  
  root - root node | 根节点
  
  Returns:
  
  parallel stream of nodes | 节点并行流
- breadthFirstStream
  
  public static <T> Stream<TreeNode<T>> breadthFirstStream(TreeNode<T> root)
  
  Creates a breadth-first stream 创建广度优先流
  
  Type Parameters:
  
  T - data type | 数据类型
  
  Parameters:
  
  root - root node | 根节点
  
  Returns:
  
  stream of nodes | 节点流
- postOrderStream
  
  public static <T> Stream<TreeNode<T>> postOrderStream(TreeNode<T> root)
  
  Creates a post-order stream 创建后序流
  
  Type Parameters:
  
  T - data type | 数据类型
  
  Parameters:
  
  root - root node | 根节点
  
  Returns:
  
  stream of nodes | 节点流
- preOrderIterator
  
  public static <T> Iterator<TreeNode<T>> preOrderIterator(TreeNode<T> root)
  
  Creates a pre-order iterator 创建前序迭代器
  
  Type Parameters:
  
  T - data type | 数据类型
  
  Parameters:
  
  root - root node | 根节点
  
  Returns:
  
  iterator | 迭代器
- preOrderIterator
  
  public static <T extends Treeable<T,ID>, ID> Iterator<T> preOrderIterator(List<T> roots)
  
  Creates a pre-order iterator for Treeable 创建Treeable的前序迭代器
  
  Type Parameters:
  
  T - node type | 节点类型
  
  ID - ID type | ID类型
  
  Parameters:
  
  roots - root nodes | 根节点列表
  
  Returns:
  
  iterator | 迭代器
- breadthFirstIterator
  
  public static <T> Iterator<TreeNode<T>> breadthFirstIterator(TreeNode<T> root)
  
  Creates a breadth-first iterator 创建广度优先迭代器
  
  Type Parameters:
  
  T - data type | 数据类型
  
  Parameters:
  
  root - root node | 根节点
  
  Returns:
  
  iterator | 迭代器
- postOrderIterator
  
  public static <T> Iterator<TreeNode<T>> postOrderIterator(TreeNode<T> root)
  
  Creates a post-order iterator 创建后序迭代器
  
  Type Parameters:
  
  T - data type | 数据类型
  
  Parameters:
  
  root - root node | 根节点
  
  Returns:
  
  iterator | 迭代器
- map
  
  public static <T,R> TreeNode<R> map(TreeNode<T> root, Function<T,R> mapper)
  
  Maps tree to new data type 将树映射到新数据类型
  
  Type Parameters:
  
  T - source type | 源类型
  
  R - result type | 结果类型
  
  Parameters:
  
  root - root node | 根节点
  
  mapper - data mapper | 数据映射器
  
  Returns:
  
  mapped tree | 映射后的树
- mapNode
  
  public static <T,R> TreeNode<R> mapNode(TreeNode<T> root, Function<TreeNode<T>, R> mapper)
  
  Maps tree with node context 带节点上下文的树映射
  
  Type Parameters:
  
  T - source type | 源类型
  
  R - result type | 结果类型
  
  Parameters:
  
  root - root node | 根节点
  
  mapper - node mapper | 节点映射器
  
  Returns:
  
  mapped tree | 映射后的树
- flatMap
  
  public static <T,R> Stream<R> flatMap(TreeNode<T> root, Function<TreeNode<T>, Stream<R>> mapper)
  
  Flat maps tree to stream 扁平映射树到流
  
  Type Parameters:
  
  T - source type | 源类型
  
  R - result type | 结果类型
  
  Parameters:
  
  root - root node | 根节点
  
  mapper - node to stream mapper | 节点到流映射器
  
  Returns:
  
  flattened stream | 扁平化流
- reduce
  
  public static <T,R> R reduce(TreeNode<T> root, R identity, BiFunction<R,T,R> accumulator)
  
  Reduces tree to single value 将树归约为单个值
  
  Type Parameters:
  
  T - data type | 数据类型
  
  R - result type | 结果类型
  
  Parameters:
  
  root - root node | 根节点
  
  identity - initial value | 初始值
  
  accumulator - accumulator | 累加器
  
  Returns:
  
  reduced value | 归约值
- reduce
  
  public static <T,R> R reduce(TreeNode<T> root, R identity, BiFunction<R,T,R> accumulator, BinaryOperator<R> combiner)
  
  Reduces tree with combiner (for parallel) 带组合器的树归约（用于并行）
  
  Type Parameters:
  
  T - data type | 数据类型
  
  R - result type | 结果类型
  
  Parameters:
  
  root - root node | 根节点
  
  identity - initial value | 初始值
  
  accumulator - accumulator | 累加器
  
  combiner - combiner | 组合器
  
  Returns:
  
  reduced value | 归约值
- foldBottomUp
  
  public static <T,R> R foldBottomUp(TreeNode<T> root, Function<T,R> leafMapper, BiFunction<T,List<R>,R> branchFolder)
  
  Folds tree bottom-up 自底向上折叠树
  
  Type Parameters:
  
  T - data type | 数据类型
  
  R - result type | 结果类型
  
  Parameters:
  
  root - root node | 根节点
  
  leafMapper - leaf node mapper | 叶节点映射器
  
  branchFolder - branch folder | 分支折叠器
  
  Returns:
  
  folded value | 折叠值
- getDescendants
  
  public static <T> List<TreeNode<T>> getDescendants(TreeNode<T> node)
  
  Gets all descendants 获取所有后代
  
  Type Parameters:
  
  T - data type | 数据类型
  
  Parameters:
  
  node - node | 节点
  
  Returns:
  
  list of descendants | 后代列表
- getSiblings
  
  public static <T> List<TreeNode<T>> getSiblings(TreeNode<T> node)
  
  Gets all siblings 获取所有兄弟节点
  
  Type Parameters:
  
  T - data type | 数据类型
  
  Parameters:
  
  node - node | 节点
  
  Returns:
  
  list of siblings | 兄弟节点列表
- getAncestors
  
  public static <T> List<TreeNode<T>> getAncestors(TreeNode<T> node)
  
  Gets ancestors from parent to root 获取从父节点到根节点的祖先
  
  Type Parameters:
  
  T - data type | 数据类型
  
  Parameters:
  
  node - node | 节点
  
  Returns:
  
  list of ancestors | 祖先列表
- getDepth
  
  public static <T> int getDepth(TreeNode<T> node)
  
  Gets the depth of a node 获取节点深度
  
  Type Parameters:
  
  T - data type | 数据类型
  
  Parameters:
  
  node - node | 节点
  
  Returns:
  
  depth (0 for root) | 深度（根节点为0）
- findLowestCommonAncestor
  
  public static <T> TreeNode<T> findLowestCommonAncestor(TreeNode<T> node1, TreeNode<T> node2)
  
  Finds lowest common ancestor 查找最近公共祖先
  
  Type Parameters:
  
  T - data type | 数据类型
  
  Parameters:
  
  node1 - first node | 第一个节点
  
  node2 - second node | 第二个节点
  
  Returns:
  
  lowest common ancestor or null | 最近公共祖先或null

Class TreeTraverser

Nested Class Summary

Method Summary

Methods inherited from class Object

Method Details

traverse

traverse

stream

stream

parallelStream

breadthFirstStream

postOrderStream

preOrderIterator

preOrderIterator

breadthFirstIterator

postOrderIterator

map

mapNode

flatMap

reduce

reduce

foldBottomUp

getDescendants

getSiblings

getAncestors

getDepth

findLowestCommonAncestor