*
   * Visited Nodes = {}
   * EndpointPair [N1, N2] - return
   * EndpointPair [N1, N3] - return
   * Visited Nodes = {N1}
   * EndpointPair [N2, N1] - skip
   * EndpointPair [N2, N3] - return
   * Visited Nodes = {N1, N2}
   * EndpointPair [N3, N1] - skip
   * EndpointPair [N3, N2] - skip
   * Visited Nodes = {N1, N2, N3}
   * EndpointPair [N4, N4] - return
   * Visited Nodes = {N1, N2, N3, N4}

 *   }
 * }.visit(type);
 * }
 *
 * <p>One {@code Type} is visited at most once. The second time the same type is visited, it's
 * ignored by {@link #visit}. This avoids infinite recursion caused by recursive type bounds.
 *
 * <p>This class is not thread safe.
 *
 * @author Ben Yu
 */
abstract class TypeVisitor {

  private final Set<Type> visited = new HashSet<>();

  /**

    fun visitTree(
        classDetails: ClassDetails,
        classesDir: File,
        jarOutputStream: JarOutputStream,
        visited: MutableSet<ClassDetails>
    ) {

        if (!visited.add(classDetails)) {
            return
        }
        if (classDetails.visited) {
            val fileName = classDetails.outputClassFilename
            val classFile = classesDir.resolve(fileName)

        return sortedNodes;
    }

    // Helper method to visit a node
    private static void visitNode(BuildStep node, Set<BuildStep> visited, List<BuildStep> sortedNodes) {
        if (visited.add(node)) {
            // For each successor of the current node, visit unvisited successors
            node.successors.forEach(successor -> visitNode(successor, visited, sortedNodes));
            sortedNodes.add(node);
        }
    }

            return g;
        }

        List<MetadataGraphVertex> visited = new ArrayList<>(g.getVertices().size());
        visit(g.getEntry(), visited, g);

        List<MetadataGraphVertex> dropList = new ArrayList<>(g.getVertices().size());

        // collect drop list
        for (MetadataGraphVertex v : g.getVertices()) {
            if (!visited.contains(v)) {
                dropList.add(v);
            }
        }

        visit(t.getActualTypeArguments());
      }

      @Override
      void visitTypeVariable(TypeVariable<?> t) {
        visit(t.getBounds());
      }
    }.visit(type);
  }

  private static void assertVisited(Type type) {
    TypeVisitor visitor = new BaseTypeVisitor();
    try {
      visitor.visit(type);
      fail("Type not visited");

        visit(t.getActualTypeArguments());
      }

      @Override
      void visitTypeVariable(TypeVariable<?> t) {
        visit(t.getBounds());
      }
    }.visit(type);
  }

  private static void assertVisited(Type type) {
    TypeVisitor visitor = new BaseTypeVisitor();
    try {
      visitor.visit(type);
      fail("Type not visited");

        ClasspathContainer cpc;

        List<MetadataGraphVertex> visited;

        // -----------------------------------------------------------------------
        protected ClasspathGraphVisitor(MetadataGraph cleanGraph, ClasspathContainer cpc) {
            this.cpc = cpc;
            this.graph = cleanGraph;

            visited = new ArrayList<>(cleanGraph.getVertices().size());
        }

        return isSuccessorOf(new HashSet<>(), step);
    }

    private boolean isSuccessorOf(Set<BuildStep> visited, BuildStep step) {
        if (this == step) {
            return true;
        } else if (visited.add(this)) {
            return this.predecessors.stream().anyMatch(n -> n.isSuccessorOf(visited, step));
        } else {
            return false;
        }
    }

    public void skip() {

    private void nonEmptyPredecessors(BuildStep step, Set<BuildStep> preds, Set<BuildStep> visited) {
        if (visited.add(step)) {
            step.predecessors.forEach(ch -> {
                if (ch.executions().findAny().isPresent()) {
                    preds.add(ch);
                } else {
                    nonEmptyPredecessors(ch, preds, visited);
                }
            });
        }
    }