/**
     * The elements to be returned by future calls to {@code next()}, with the first at the top of
     * the stack.
     */
    final Stack<E> nextElements = new Stack<>();

    /**
     * The elements to be returned by future calls to {@code previous()}, with the first at the top
     * of the stack.
     */
    final Stack<E> previousElements = new Stack<>();

    /**

    public void remove() {
      checkState(lastEntry != null);
      LocalCache.this.remove(lastEntry.getKey(), lastEntry.getValue());
      lastEntry = null;
    }
  }

  /** KeyIterator build on top of EntryIterator. */
  final class KeyIterator implements Iterator<K> {
    private EntryIterator iterator;

    KeyIterator() {
      iterator = new EntryIterator();
    }

    @Override

import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import javax.annotation.Nonnull;
import javax.annotation.meta.TypeQualifierDefault;

/**
 * Marks all "top-level" types as non-null in a way that is recognized by Kotlin. Note that this
 * unfortunately includes type-variable usages, so we also provide {@link ParametricNullness} to
 * "undo" it as best we can.
 */
@GwtCompatible

import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import javax.annotation.Nonnull;
import javax.annotation.meta.TypeQualifierDefault;

/**
 * Marks all "top-level" types as non-null in a way that is recognized by Kotlin. Note that this
 * unfortunately includes type-variable usages, so we also provide {@link ParametricNullness} to
 * "undo" it as best we can.
 */
@GwtCompatible

    void setDegreeOfConcurrency(int degreeOfConcurrency);

    /**
     * @return the degree of concurrency for the build.
     */
    int getDegreeOfConcurrency();

    // Recursive (really to just process the top-level POM)
    MavenExecutionRequest setRecursive(boolean recursive);

    boolean isRecursive();

    MavenExecutionRequest setPom(File pom);

    File getPom();

    // Errors

        createLocalArtifact("h", "1.0");
        artifactResolver.resolveTransitively(
                Collections.singleton(g), projectArtifact, remoteRepositories(), localRepository(), null);

        // we want to see all top-level thread groups
        ThreadGroup tg = Thread.currentThread().getThreadGroup();
        while (tg.getParent() == null) {
            tg = tg.getParent();
        }

    public static final String LDAP_MEMBEROF_ATTRIBUTE = "ldap.memberof.attribute";

    public static final String NOTIFICATION_LOGIN = "notification.login";

    public static final String NOTIFICATION_SEARCH_TOP = "notification.search.top";

    public static final String NOTIFICATION_ADVANCE_SEARCH = "notification.advance.search";

    public static final String STORAGE_ENDPOINT = "storage.endpoint";

     * directory pointed at by the {@code -f/--file} command line argument.
     */
    @Nonnull
    Path getTopDirectory();

    /**
     * Gets the root directory of the session, which is the root directory for the top directory project.
     *
     * @throws IllegalStateException if the root directory could not be found
     * @see #getTopDirectory()
     * @see Project#getRootDirectory()
     */
    @Nonnull

     * filter is applied (like in Maven 3).
     * <p>
     * Supported filters:
     * <ul>
     *     <li>"h" or "h(num)" - highest version or top list of highest ones filter</li>
     *     <li>"l" or "l(num)" - lowest version or bottom list of lowest ones filter</li>
     *     <li>"s" - contextual snapshot filter</li>

    }

    default void setNotificationSearchTop(final String value) {
        setSystemProperty(Constants.NOTIFICATION_SEARCH_TOP, value);
    }

    default String getNotificationSearchTop() {
        return getSystemProperty(Constants.NOTIFICATION_SEARCH_TOP, StringUtil.EMPTY);
    }

    default String getUserAgentName() {