*
   * <p><b>Java 8+ users:</b> use the lambda expression {@code o -> value} instead.
   *
   * @param value the constant value for the function to return
   * @return a function that always returns {@code value}
   */
  public static <E extends @Nullable Object> Function<@Nullable Object, E> constant(
      @ParametricNullness E value) {
    return new ConstantFunction<>(value);
  }

       * because the null check on the theUnsafe object remains inside the loop and
       * BYTE_ARRAY_BASE_OFFSET doesn't get constant-folded.
       *
       * The compiler can treat static final fields as compile-time constants and can constant-fold
       * them while (final or not) local variables are run time values.
       */

      static final Unsafe theUnsafe = getUnsafe();

 * supported. The elements can be any objects.
 *
 * <p>{@code contains(x)}, {@code add(x)} and {@code remove(x)}, are all (expected and amortized)
 * constant time operations. Expected in the hashtable sense (depends on the hash function doing a
 * good job of distributing the elements to the buckets to a distribution not far from uniform), and

import java.util.PriorityQueue;
import java.util.Queue;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A double-ended priority queue, which provides constant-time access to both its least element and
 * its greatest element, as determined by the queue's specified comparator. If no comparator is
 * given at creation time, the natural order of elements is used. If no maximum size is given at

        checkNotNull(columnKey, "columnKey"),
        checkNotNull(value, "value"));
  }

  /**
   * A builder for creating immutable table instances, especially {@code public static final} tables
   * ("constant tables"). Example:
   *
   * <pre>{@code
   * static final ImmutableTable<Integer, Character, String> SPREADSHEET =
   *     new ImmutableTable.Builder<Integer, Character, String>()
   *         .put(1, 'A', "foo")

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.util.concurrent;

import static com.google.common.base.Functions.constant;
import static com.google.common.base.Functions.identity;
import static com.google.common.base.Throwables.propagateIfInstanceOf;
import static com.google.common.collect.Iterables.getOnlyElement;

  public static <K, V> Builder<K, V> builder() {
    return new Builder<>();
  }

  /**
   * A builder for creating immutable {@code SetMultimap} instances, especially {@code public static
   * final} multimaps ("constant multimaps"). Example:
   *
   * <pre>{@code
   * static final Multimap<String, Integer> STRING_TO_INTEGER_MULTIMAP =
   *     new ImmutableSetMultimap.Builder<String, Integer>()
   *         .put("one", 1)

   */
  public static <K, V> Builder<K, V> builder() {
    return new Builder<>();
  }

  /**
   * A builder for creating immutable multimap instances, especially {@code public static final}
   * multimaps ("constant multimaps"). Example:
   *
   * <pre>{@code
   * static final Multimap<String, Integer> STRING_TO_INTEGER_MULTIMAP =
   *     new ImmutableMultimap.Builder<String, Integer>()
   *         .put("one", 1)

    checkNonnegative(expectedSize, "expectedSize");
    return new Builder<>(expectedSize);
  }

  /**
   * A builder for creating immutable bimap instances, especially {@code public static final} bimaps
   * ("constant bimaps"). Example:
   *
   * <pre>{@code
   * static final ImmutableBiMap<String, Integer> WORD_TO_INT =
   *     new ImmutableBiMap.Builder<String, Integer>()
   *         .put("one", 1)

   */
  public static <K, V> Builder<K, V> builder() {
    return new Builder<>();
  }

  /**
   * A builder for creating immutable multimap instances, especially {@code public static final}
   * multimaps ("constant multimaps"). Example:
   *
   * <pre>{@code
   * static final Multimap<String, Integer> STRING_TO_INTEGER_MULTIMAP =
   *     new ImmutableMultimap.Builder<String, Integer>()
   *         .put("one", 1)