* @since 20.0
 */
@DoNotMock
public final class GraphBuilder<N> extends AbstractGraphBuilder<N> {

  /** Creates a new instance with the specified edge directionality. */
  private GraphBuilder(boolean directed) {
    super(directed);
  }

  /** Returns a {@link GraphBuilder} for building directed graphs. */
  public static GraphBuilder<Object> directed() {
    return new GraphBuilder<>(true);
  }

import org.apache.maven.model.building.Result;

/**
 * Builds the {@link ProjectDependencyGraph inter-dependencies graph} between projects in the reactor.
 *
 * @since 3.0-alpha
 */
public interface GraphBuilder {
    String HINT = "graphBuilder";

    Result<? extends ProjectDependencyGraph> build(MavenSession session);

  }

  /**
   * Tests that the ImmutableGraph.Builder doesn't change when the creating GraphBuilder changes.
   */
  @Test
  @SuppressWarnings("CheckReturnValue")
  public void immutableGraphBuilder_copiesGraphBuilder() {
    GraphBuilder<String> graphBuilder =
        GraphBuilder.directed()
            .allowsSelfLoops(true)
            .<String>nodeOrder(ElementOrder.<String>natural());

  @Test
  public void directedGraph() {
    testGraphMutation(GraphBuilder.directed());
  }

  @Test
  public void undirectedGraph() {
    testGraphMutation(GraphBuilder.undirected());
  }

  private static void testGraphMutation(GraphBuilder<? super Integer> graphBuilder) {
    Random gen = new Random(42); // Fixed seed so test results are deterministic.

  private ImmutableGraph.Builder<Integer> graphBuilder;

  public StandardImmutableDirectedGraphTest(boolean allowsSelfLoops) {
    this.allowsSelfLoops = allowsSelfLoops;
  }

  @Override
  public Graph<Integer> createGraph() {
    graphBuilder = GraphBuilder.directed().allowsSelfLoops(allowsSelfLoops).immutable();
    return graphBuilder.build();
  }

  @Override
  final void addNode(Integer n) {

  private ImmutableGraph.Builder<Integer> graphBuilder;

  public StandardImmutableUndirectedGraphTest(boolean allowsSelfLoops) {
    this.allowsSelfLoops = allowsSelfLoops;
  }

  @Override
  public Graph<Integer> createGraph() {
    graphBuilder = GraphBuilder.undirected().allowsSelfLoops(allowsSelfLoops).immutable();
    return graphBuilder.build();
  }

  @Override
  final void addNode(Integer n) {

  public void immutableValueGraphBuilder_copiesGraphBuilder() {
    ValueGraphBuilder<String, Object> graphBuilder =
        ValueGraphBuilder.directed()
            .allowsSelfLoops(true)
            .<String>nodeOrder(ElementOrder.<String>natural());
    ImmutableValueGraph.Builder<String, Integer> immutableValueGraphBuilder =
        graphBuilder.<String, Integer>immutable();

  @Test
  public void directedGraph() {
    testGraphMutation(GraphBuilder.directed());
  }

  @Test
  public void undirectedGraph() {
    testGraphMutation(GraphBuilder.undirected());
  }

  private static void testGraphMutation(GraphBuilder<? super Integer> graphBuilder) {
    Random gen = new Random(42); // Fixed seed so test results are deterministic.

  public void immutableValueGraphBuilder_copiesGraphBuilder() {
    ValueGraphBuilder<String, Object> graphBuilder =
        ValueGraphBuilder.directed()
            .allowsSelfLoops(true)
            .<String>nodeOrder(ElementOrder.<String>natural());
    ImmutableValueGraph.Builder<String, Integer> immutableValueGraphBuilder =
        graphBuilder.<String, Integer>immutable();

import com.google.common.graph.GraphConstants.Presence;

/**
 * Standard implementation of {@link MutableGraph} that supports both directed and undirected
 * graphs. Instances of this class should be constructed with {@link GraphBuilder}.
 *
 * <p>Time complexities for mutation methods are all O(1) except for {@code removeNode(N node)},
 * which is in O(d_node) where d_node is the degree of {@code node}.
 *
 * @author James Sexton