protected char @Nullable [] escape(int cp) {
            return ('a' <= cp && cp <= 'z') ? new char[] {Character.toUpperCase((char) cp)} : null;
          }
          // Inefficient implementation that defines all letters as escapable.
          @Override
          protected int nextEscapeIndex(CharSequence csq, int index, int end) {
            while (index < end && !Character.isLetter(csq.charAt(index))) {
              index++;

    return requireNonNull(predecessor);
  }

  private int[] requireSuccessors() {
    return requireNonNull(successor);
  }

  /*
   * We don't define getPredecessor+getSuccessor and setPredecessor+setSuccessor here because
   * they're defined above -- including logic to add and subtract 1 to map between the values stored
   * in the predecessor/successor arrays and the indexes in the elements array that they identify.
   */

import com.google.common.annotations.GwtCompatible;

/**
 * Low-level, high-performance utility methods related to the {@linkplain Charsets#UTF_8 UTF-8}
 * character encoding. UTF-8 is defined in section D92 of <a
 * href="http://www.unicode.org/versions/Unicode6.2.0/ch03.pdf">The Unicode Standard Core
 * Specification, Chapter 3</a>.
 *

  }

  @Override
  public Set<E> outEdges() {
    return Collections.unmodifiableSet(outEdgeMap.keySet());
  }

  @Override
  public N adjacentNode(E edge) {
    // Since the reference node is defined to be 'source' for directed graphs,
    // we can assume this edge lives in the set of outgoing edges.
    // (We're relying on callers to call this method only with an edge that's in the graph.)

 * high contention, expected throughput of this class is significantly higher, at the expense of
 * higher space consumption.
 *
 * <p>This class extends {@link Number}, but does not define methods such as {@code
 * equals}, {@code hashCode} and {@code compareTo} because instances are expected to be mutated, and
 * so are not useful as collection keys.
 *

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.errorprone.annotations.DoNotMock;

/**
 * A builder for constructing instances of {@link MutableGraph} or {@link ImmutableGraph} with
 * user-defined properties.
 *
 * <p>A {@code Graph} built by this class has the following default properties:
 *
 * <ul>
 *   <li>does not allow self-loops

/**
 * Provides static methods for serializing collection classes.
 *
 * <p>This class assists the implementation of collection classes. Do not use this class to
 * serialize collections that are defined elsewhere.
 *
 * @author Jared Levy
 */
@GwtIncompatible
@J2ktIncompatible
@ElementTypesAreNonnullByDefault
final class Serialization {
  private Serialization() {}

  /**

import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import javax.annotation.CheckForNull;

/**
 * This class provides default values for all Java types, as defined by the JLS.
 *
 * @author Ben Yu
 * @since 1.0
 */
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
public final class Defaults {
  private Defaults() {}

          protected char @Nullable [] escape(int cp) {
            return ('a' <= cp && cp <= 'z') ? new char[] {Character.toUpperCase((char) cp)} : null;
          }
          // Inefficient implementation that defines all letters as escapable.
          @Override
          protected int nextEscapeIndex(CharSequence csq, int index, int end) {
            while (index < end && !Character.isLetter(csq.charAt(index))) {
              index++;

    assertThat(networkA.edgeOrder()).isEqualTo(networkB.edgeOrder());

    assertThat(networkA).isEqualTo(networkB);
  }

  /**
   * In some cases our graph implementations return custom sets that define their own size() and
   * contains(). Verify that these sets are consistent with the elements of their iterator.
   */
  @CanIgnoreReturnValue
  static <T> Set<T> sanityCheckSet(Set<T> set) {