}
      };

  enum NullListener implements RemovalListener<Object, Object> {
    INSTANCE;

    @Override
    public void onRemoval(RemovalNotification<Object, Object> notification) {}
  }

  enum OneWeigher implements Weigher<Object, Object> {
    INSTANCE;

    @Override
    public int weigh(Object key, Object value) {
      return 1;
    }
  }

     * date. This incremental Sitemap fetching mechanism allows for the rapid
     * discovery of new URLs on very large sites.
     */
    private String lastmod;

    /**
     * Creates a new SitemapFile instance.
     */
    public SitemapFile() {
        // Default constructor
    }

    /*
     * (non-Javadoc)
     *
     * @see org.codelibs.fess.crawler.entity.Sitemap#getLoc()
     */
    @Override

import com.google.common.base.MoreObjects;
import java.util.Objects;
import java.util.concurrent.Callable;
import org.jspecify.annotations.Nullable;

/**
 * Statistics about the performance of a {@link Cache}. Instances of this class are immutable.
 *
 * <p>Cache statistics are incremented according to the following rules:
 *
 * <ul>
 *   <li>When a cache lookup encounters an existing cache entry {@code hitCount} is incremented.

import com.google.common.base.MoreObjects;
import java.util.Objects;
import java.util.concurrent.Callable;
import org.jspecify.annotations.Nullable;

/**
 * Statistics about the performance of a {@link Cache}. Instances of this class are immutable.
 *
 * <p>Cache statistics are incremented according to the following rules:
 *
 * <ul>
 *   <li>When a cache lookup encounters an existing cache entry {@code hitCount} is incremented.

            "No mapping between account names and security IDs was done.", "The security ID structure is invalid.",
            "The file system is full.", "All pipe instances are busy.", "All pipe instances are busy.", "The pipe state is invalid.",
            "All pipe instances are busy.", "No process is on the other end of the pipe.", "The pipe is being closed.",

    //                                                                           =========
    private static final DuplicateHostDbm _instance = new DuplicateHostDbm();

    private DuplicateHostDbm() {
    }

    public static DuplicateHostDbm getInstance() {
        return _instance;
    }

    // ===================================================================================

    //                                                                           =========
    private static final RelatedQueryDbm _instance = new RelatedQueryDbm();

    private RelatedQueryDbm() {
    }

    public static RelatedQueryDbm getInstance() {
        return _instance;
    }

    // ===================================================================================

    //                                                                           =========
    private static final RoleTypeDbm _instance = new RoleTypeDbm();

    private RoleTypeDbm() {
    }

    public static RoleTypeDbm getInstance() {
        return _instance;
    }

    // ===================================================================================

   * on arbitrary {@link Map} classes.
   *
   * <p>The {@code factory}-generated and {@code backingMap} classes determine the table iteration
   * order. However, the table's {@code row()} method returns instances of a different class than
   * {@code factory.get()} does.
   *
   * <p>Call this method only when the simpler factory methods in classes like {@link
   * HashBasedTable} and {@link TreeBasedTable} won't suffice.
   *

    @Override
    public boolean equals(@Nullable Object obj) {
      return obj instanceof ConstructorParameterSingleValue;
    }

    @Override
    public int hashCode() {
      return 1;
    }

    public static class Singleton {
      public static final Singleton INSTANCE = new Singleton();

      private Singleton() {}
    }
  }