/**
   * Returns a function that delegates to the {@link Interner#intern} method of the given interner.
   *
   * @since 8.0
   */
  public static <E> Function<E, E> asFunction(Interner<E> interner) {
    return new InternerFunction<>(checkNotNull(interner));
  }

  private static class InternerFunction<E> implements Function<E, E> {

    private final Interner<E> interner;

    public InternerFunction(Interner<E> interner) {

  /**
   * Returns a function that delegates to the {@link Interner#intern} method of the given interner.
   *
   * @since 8.0
   */
  public static <E> Function<E, E> asFunction(Interner<E> interner) {
    return new InternerFunction<>(checkNotNull(interner));
  }

  private static class InternerFunction<E> implements Function<E, E> {

    private final Interner<E> interner;

    public InternerFunction(Interner<E> interner) {

    assertSame(canonical, pool.intern(not));
  }

  public void testWeak_null() {
    Interner<String> pool = Interners.newWeakInterner();
    assertThrows(NullPointerException.class, () -> pool.intern(null));
  }

  public void testWeak_builder() {
    int concurrencyLevel = 42;
    Interner<Object> interner =
        Interners.newBuilder().weak().concurrencyLevel(concurrencyLevel).build();

import com.google.caliper.Benchmark;

/**
 * Benchmarking interners.
 *
 * @author Dimitris Andreou
 */
public class InternersBenchmark {
  @Benchmark
  int weakInterner(int reps) {
    Interner<String> interner = Interners.newWeakInterner();
    for (int i = 0; i < reps; i++) {
      String unused = interner.intern(Double.toHexString(Math.random()));
    }
    return reps;
  }

  @Benchmark

 * are available from the {@link Interners} class.
 *
 * <p>Note that {@code String.intern()} has some well-known performance limitations, and should
 * generally be avoided. Prefer {@link Interners#newWeakInterner} or another {@code Interner}
 * implementation even for {@code String} interning.
 *
 * @author Kevin Bourrillion
 * @since 3.0
 */
@DoNotMock("Use Interners.new*Interner")
@J2ktIncompatible
@GwtIncompatible

    assertSame(canonical, pool.intern(not));
  }

  public void testWeak_null() {
    Interner<String> pool = Interners.newWeakInterner();
    assertThrows(NullPointerException.class, () -> pool.intern(null));
  }

  public void testWeak_builder() {
    int concurrencyLevel = 42;
    Interner<Object> interner =
        Interners.newBuilder().weak().concurrencyLevel(concurrencyLevel).build();

 * are available from the {@link Interners} class.
 *
 * <p>Note that {@code String.intern()} has some well-known performance limitations, and should
 * generally be avoided. Prefer {@link Interners#newWeakInterner} or another {@code Interner}
 * implementation even for {@code String} interning.
 *
 * @author Kevin Bourrillion
 * @since 3.0
 */
@DoNotMock("Use Interners.new*Interner")
@J2ktIncompatible
@GwtIncompatible

import com.google.caliper.Benchmark;

/**
 * Benchmarking interners.
 *
 * @author Dimitris Andreou
 */
public class InternersBenchmark {
  @Benchmark
  int weakInterner(int reps) {
    Interner<String> interner = Interners.newWeakInterner();
    for (int i = 0; i < reps; i++) {
      String unused = interner.intern(Double.toHexString(Math.random()));
    }
    return reps;
  }

  @Benchmark

    WeakInternerImpl {
      @Override
      public <E> Interner<E> create(Collection<E> contents) {
        Interner<E> interner = Interners.newWeakInterner();
        for (E e : contents) {
          E unused = interner.intern(e);
        }
        return interner;
      }
    },
    StrongInternerImpl {
      @Override
      public <E> Interner<E> create(Collection<E> contents) {

 * an example, see {@link ForwardingCollection}.
 *
 * <h2>Other</h2>
 *
 * <ul>
 *   <li>{@link EvictingQueue}
 *   <li>{@link Interner}, {@link Interners}
 *   <li>{@link MapMaker}
 *   <li>{@link MinMaxPriorityQueue}
 *   <li>{@link PeekingIterator}
 * </ul>
 */
@CheckReturnValue
@ParametersAreNonnullByDefault
package com.google.common.collect;