}
    return totalSize;
  }

  /**
   * Peeks into the cache's internals to check its internal consistency. Verifies that each
   * segment's count matches its #elements (after cleanup), each segment is unlocked, each entry
   * contains a non-null key and value, and the eviction and expiration queues are consistent (see
   * {@link #checkEviction}, {@link #checkExpiration}).
   */
  static void checkValidState(Cache<?, ?> cache) {

package org.apache.maven.plugin;

import org.apache.maven.project.ProjectBuildingException;
import org.apache.maven.project.artifact.InvalidDependencyVersionException;

/**
 * Thrown when a plugin is not internally consistent.
 *
 */
public class InvalidPluginException extends Exception {
    public InvalidPluginException(String message, ProjectBuildingException e) {
        super(message, e);
    }

  }

  /**
   * Creates a function that returns the same boolean output as the given predicate for all inputs.
   *
   * <p>The returned function is <i>consistent with equals</i> (as documented at {@link
   * Function#apply}) if and only if {@code predicate} is itself consistent with equals.
   *
   * <p><b>Java 8+ users:</b> use the method reference {@code predicate::test} instead.
   */

  }

  /**
   * Creates a function that returns the same boolean output as the given predicate for all inputs.
   *
   * <p>The returned function is <i>consistent with equals</i> (as documented at {@link
   * Function#apply}) if and only if {@code predicate} is itself consistent with equals.
   *
   * <p><b>Java 8+ users:</b> use the method reference {@code predicate::test} instead.
   */

      assertTrue(item + " must be equivalent to itself", equivalence.equivalent(item, item));
      assertEquals(
          "the hash of " + item + " must be consistent",
          equivalence.hash(item),
          equivalence.hash(item));
    }
  }

   * <p>The {@code hash} has the following properties:
   *
   * <ul>
   *   <li>It is <i>consistent</i>: for any reference {@code x}, multiple invocations of {@code
   *       hash(x}} consistently return the same value provided {@code x} remains unchanged
   *       according to the definition of the equivalence. The hash need not remain consistent from
   *       one execution of an application to another execution of the same application.

   *
   * <p>The {@code hash} has the following properties:
   *
   * <ul>
   *   <li>It is <i>consistent</i>: for any reference {@code x}, multiple invocations of {@code
   *       hash(x}} consistently return the same value provided {@code x} remains unchanged
   *       according to the definition of the equivalence. The hash need not remain consistent from
   *       one execution of an application to another execution of the same application.

    }
    return totalSize;
  }

  /**
   * Peeks into the cache's internals to check its internal consistency. Verifies that each
   * segment's count matches its #elements (after cleanup), each segment is unlocked, each entry
   * contains a non-null key and value, and the eviction and expiration queues are consistent (see
   * {@link #checkEviction}, {@link #checkExpiration}).
   */
  static void checkValidState(Cache<?, ?> cache) {

  @Override
  public Set<V> values() {
    /*
     * We can almost reuse the inverse's keySet, except we have to fix the
     * iteration order so that it is consistent with the forward map.
     */
    Set<V> result = valueSet;
    return (result == null) ? valueSet = new ValueSet() : result;
  }

  @WeakOuter
  private class ValueSet extends ForwardingSet<V> {

   * without grabbing the lock.
   *
   * <p>To update this field correctly the lock must be held to guarantee that the state is
   * consistent.
   */
  private volatile StateSnapshot snapshot = new StateSnapshot(NEW);

  /** Constructor for use by subclasses. */
  protected AbstractService() {}

  /**