Package org.openrewrite.maven.graph

Class DependencyTreeWalker

java.lang.Object

org.openrewrite.maven.graph.DependencyTreeWalker

public class DependencyTreeWalker
extends Object

Walks a dependency tree lazily, finding dependencies that match a given matcher. Uses depth-first pre-order traversal with cycle detection to avoid infinite loops. Pre-order means parent dependencies are visited before their children.

This class encapsulates the common pattern used by dependency insight recipes to traverse dependency trees without creating intermediate objects for non-matching dependencies, reducing GC pressure on large dependency graphs.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	DependencyTreeWalker.Callback	Callback interface for handling dependencies during tree traversal.
static class	DependencyTreeWalker.Matches<S>	Collects dependency match information while walking the dependency tree.

Constructor Summary

Constructors

Constructor	Description
DependencyTreeWalker()

Method Summary

Modifier and Type	Method	Description
static String	renderPath(String scopeOrConfig, Deque<ResolvedDependency> dependencyPath)	Renders a dependency path as an inverse tree string for display.
static void	walk(List<ResolvedDependency> roots, @Nullable org.openrewrite.semver.DependencyMatcher matcher, DependencyTreeWalker.Callback callback)	Walks the dependency tree starting from the given roots, calling the callback for each dependency that matches the matcher (or all dependencies if matcher is null).
static void	walk(ResolvedDependency root, @Nullable org.openrewrite.semver.DependencyMatcher matcher, DependencyTreeWalker.Callback callback)	Walks a single dependency tree, calling the callback for each match.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

DependencyTreeWalker

public DependencyTreeWalker()

Method Details

walk

public static void walk(List<ResolvedDependency> roots,
 @Nullable org.openrewrite.semver.DependencyMatcher matcher,
 DependencyTreeWalker.Callback callback)

Walks the dependency tree starting from the given roots, calling the callback for each dependency that matches the matcher (or all dependencies if matcher is null). Uses caching to avoid re-traversing duplicate dependencies.

Parameters:

roots - the direct dependencies to start traversal from

matcher - the matcher to test dependencies against, or null to visit all

callback - called for each matching dependency with its path

walk

public static void walk(ResolvedDependency root,
 @Nullable org.openrewrite.semver.DependencyMatcher matcher,
 DependencyTreeWalker.Callback callback)

Walks a single dependency tree, calling the callback for each match.

Parameters:

root - the direct dependency to start traversal from

matcher - the matcher to test dependencies against, or null to visit all

callback - called for each matching dependency with its path

renderPath

public static String renderPath(String scopeOrConfig,
 Deque<ResolvedDependency> dependencyPath)

Renders a dependency path as an inverse tree string for display. Shows the matched dependency at the top, with parents indented below, ending with the scope/configuration.

Example output for a transitive dependency:

 matched:artifact:1.0
 \--- parent:artifact:2.0
      \--- direct:artifact:3.0
           \--- compile
 

Parameters:

scopeOrConfig - the scope (Maven) or configuration name (Gradle)

dependencyPath - the path in leaf-to-root order (matched dependency first, direct dependency last)

Returns:

formatted inverse dependency tree string