import org.eclipse.aether.graph.DependencyNode;

class WrapperNode extends AbstractNode {
    protected final Node delegate;
    protected final List<Node> children;

    WrapperNode(Node delegate, List<Node> children) {
        this.delegate = delegate;
        this.children = children;
    }

    @Override
    DependencyNode getDependencyNode() {
        return Utils.cast(AbstractNode.class, delegate, "delegate").getDependencyNode();

import org.eclipse.aether.graph.DependencyNode;

class WrapperNode extends AbstractNode {
    protected final Node delegate;
    protected final List<Node> children;

    WrapperNode(Node delegate, List<Node> children) {
        this.delegate = delegate;
        this.children = children;
    }

    @Override
    DependencyNode getDependencyNode() {
        return Utils.cast(AbstractNode.class, delegate, "delegate").getDependencyNode();

    }

    private static List<String> visitCycle(
            Map<String, Set<String>> graph,
            Collection<String> children,
            Map<String, DfsState> stateMap,
            LinkedList<String> cycle) {
        if (children != null) {
            for (String v : children) {
                DfsState state = stateMap.putIfAbsent(v, DfsState.VISITING);
                if (state == null) {

     * Traverses this node and potentially its children using the specified visitor.
     *
     * @param visitor the visitor to call back, must not be {@code null}
     * @return {@code true} to visit siblings nodes of this node as well, {@code false} to skip siblings
     */
    boolean accept(@Nonnull NodeVisitor visitor);

    /**
     * Returns a new tree starting at this node, filtering the children.

        return visitor.leave(this);
    }

    @Override
    public Node filter(Predicate<Node> filter) {
        List<Node> children =
                getChildren().stream().filter(filter).map(n -> n.filter(filter)).collect(Collectors.toList());
        return new WrapperNode(this, Collections.unmodifiableList(children));
    }

    @Override
    public String asString() {
        StringBuilder sb = new StringBuilder();

import static org.apache.maven.api.services.BaseRequest.nonNull;

/**
 * A Source specific to load POMs.  The {@link #resolve(ModelLocator, String)} method
 * will be used to find POMs for children modules.
 *
 * @since 4.0.0
 */
public interface ModelSource extends Source {

    interface ModelLocator {
        /**
         * Returns the file containing the pom or null if a pom can not be

    }

    private static List<String> visitAll(
            Collection<Vertex> children, Map<Vertex, DfsState> stateMap, List<String> list) {
        for (Vertex v : children) {
            DfsState state = stateMap.putIfAbsent(v, DfsState.VISITING);
            if (state == null) {
                visitAll(v.children, stateMap, list);
                stateMap.put(v, DfsState.VISITED);
                list.add(v.label);

            throws ProjectBuildingException;

    /**
     * Builds the projects for the specified POM files and optionally their children.
     *
     * @param pomFiles The POM files to build, must not be {@code null}.
     * @param recursive {@code true} to recursively build submodules referenced by the POM files, {@code false} to