}

    protected final ProtoLookup protoLookup;

    public LookupInvoker(ProtoLookup protoLookup) {
        this.protoLookup = requireNonNull(protoLookup);
    }

    @Override
    public int invoke(R invokerRequest) throws InvokerException {
        requireNonNull(invokerRequest);

        Properties oldProps = (Properties) System.getProperties().clone();

import org.apache.maven.model.superpom.SuperPomProvider;
import org.apache.maven.model.validation.DefaultModelValidator;
import org.apache.maven.model.validation.ModelValidator;

import static java.util.Objects.requireNonNull;

/**
 * A factory to create model builder instances when no dependency injection is available. Note: This class is

import static java.nio.file.attribute.AclEntryFlag.FILE_INHERIT;
import static java.nio.file.attribute.AclEntryType.ALLOW;
import static java.nio.file.attribute.PosixFilePermissions.asFileAttribute;
import static java.util.Objects.requireNonNull;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.collect.ImmutableList;

            String groupId,
            String artifactId,
            String classifier,
            String extension,
            String version,
            String message) {
        this.artifact = Objects.requireNonNull(artifact, "artifact cannot be null");
        this.groupId = (groupId != null && !groupId.isEmpty()) ? groupId : null;
        this.artifactId = (artifactId != null && !artifactId.isEmpty()) ? artifactId : null;

        this.modelProcessor = modelProcessor;
    }

    @Override
    public Model getSuperModel(String version) {
        return SUPER_MODELS.computeIfAbsent(Objects.requireNonNull(version), v -> {
            String resource = "/org/apache/maven/model/pom-" + v + ".xml";

            InputStream is = getClass().getResourceAsStream(resource);

            if (is == null) {

   * types (or if the type is a non-variable type, like {@code String}), then code should almost
   * never use this method, preferring instead to call {@code requireNonNull} so as to benefit from
   * its runtime check.
   *
   * <p>An example use case for this method is in implementing an {@code Iterator<T>} whose {@code

   * types (or if the type is a non-variable type, like {@code String}), then code should almost
   * never use this method, preferring instead to call {@code requireNonNull} so as to benefit from
   * its runtime check.
   *
   * <p>An example use case for this method is in implementing an {@code Iterator<T>} whose {@code

    /**
     * Creates a new source backed by the specified URL.
     *
     * @param url The file, must not be {@code null}.
     */
    public UrlSource(URL url) {
        this.url = Objects.requireNonNull(url, "url cannot be null");
        this.hashCode = Objects.hashCode(url);
    }

    @Override
    public InputStream getInputStream() throws IOException {
        return url.openStream();
    }

     */
    public void merge(
            org.apache.maven.model.Model target,
            org.apache.maven.model.Model source,
            boolean sourceDominant,
            Map<?, ?> hints) {
        Objects.requireNonNull(target, "target cannot be null");
        if (source == null) {
            return;
        }
        target.update(merge(target.getDelegate(), source.getDelegate(), sourceDominant, hints));
    }

  }

  @SuppressWarnings("unchecked") // we must carefully only allow Es to get in
  E elementData(int index) {
    /*
     * requireNonNull is safe as long as we're careful to call this method only with populated
     * indexes.
     */
    return (E) requireNonNull(queue[index]);
  }

  @Override
  @CheckForNull
  public E peek() {
    return isEmpty() ? null : elementData(0);
  }