*
   * @param deque the deque to be wrapped in a synchronized view
   * @return a synchronized view of the specified deque
   * @since 15.0
   */
  @J2ktIncompatible // Synchronized
  public static <E extends @Nullable Object> Deque<E> synchronizedDeque(Deque<E> deque) {
    return Synchronized.deque(deque, null);
  }

   *
   * @param deque the deque to be wrapped in a synchronized view
   * @return a synchronized view of the specified deque
   * @since 15.0
   */
  @J2ktIncompatible // Synchronized
  public static <E extends @Nullable Object> Deque<E> synchronizedDeque(Deque<E> deque) {
    return Synchronized.deque(deque, null);
  }

    private Map<String, Map<String, Map<String, MavenProject>>> allProjects;
    private Path projectLocalRepository;
    // projectId -> Deque<lifecycle>
    private final Map<String, Deque<String>> lifecycles = new ConcurrentHashMap<>();

    @Inject
    ReactorReader(MavenSession session) {
        this.session = session;

import com.google.common.annotations.Beta;
import com.google.common.annotations.GwtCompatible;
import com.google.common.base.Function;
import java.util.ArrayDeque;
import java.util.Deque;
import java.util.Iterator;
import java.util.Queue;
import java.util.function.Consumer;
import javax.annotation.CheckForNull;

/**

  }

  static <E extends @Nullable Object> Deque<E> deque(Deque<E> deque, @CheckForNull Object mutex) {
    return new SynchronizedDeque<>(deque, mutex);
  }

  static final class SynchronizedDeque<E extends @Nullable Object> extends SynchronizedQueue<E>
      implements Deque<E> {

    SynchronizedDeque(Deque<E> delegate, @CheckForNull Object mutex) {
      super(delegate, mutex);
    }

  }

  static <E extends @Nullable Object> Deque<E> deque(Deque<E> deque, @CheckForNull Object mutex) {
    return new SynchronizedDeque<>(deque, mutex);
  }

  static final class SynchronizedDeque<E extends @Nullable Object> extends SynchronizedQueue<E>
      implements Deque<E> {

    SynchronizedDeque(Deque<E> delegate, @CheckForNull Object mutex) {
      super(delegate, mutex);
    }

    private static class ActivationWalker extends MavenTransformer {

        private final Deque<ActivationFrame> stk;

        ActivationWalker(Deque<ActivationFrame> stk, UnaryOperator<String> transformer) {
            super(transformer);
            this.stk = stk;
        }

 * under the License.
 */
package org.apache.maven.artifact.versioning;

import java.math.BigInteger;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Deque;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import java.util.Objects;
import java.util.Properties;

/**
 * <p>
 * Generic implementation of version comparison.
 * </p>

import com.google.errorprone.annotations.InlineMe;
import com.google.errorprone.annotations.InlineMeValidationDisabled;
import java.util.ArrayDeque;
import java.util.Collection;
import java.util.Deque;
import java.util.Iterator;
import java.util.OptionalDouble;
import java.util.OptionalInt;
import java.util.OptionalLong;
import java.util.PrimitiveIterator;
import java.util.Spliterator;
import java.util.Spliterators;

     * meta-iterators rather than letting the nesting get arbitrarily deep.  This keeps each
     * operation O(1).
     */

    @CheckForNull private Iterator<? extends Iterator<? extends T>> topMetaIterator;

    // Only becomes nonnull if we encounter nested concatenations.
    @CheckForNull private Deque<Iterator<? extends Iterator<? extends T>>> metaIterators;