* class. For example, testing that {@code nodes()} method returns the set of the nodes in the
 * graph. The following test cases are left for the subclasses to handle:
 *
 * <ul>
 *   <li>Test cases related to whether the graph is directed or undirected.
 *   <li>Test cases related to the specific implementation of the {@link Graph} interface.
 * </ul>
 *

 * </ul>
 *
 * @since 14.0
 * @author Colin Decker
 */
@J2ktIncompatible
@GwtIncompatible
public abstract class CharSource {

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

  /**
   * Returns a {@link ByteSource} view of this char source that encodes chars read from this source
   * as bytes using the given {@link Charset}.
   *

 * </ul>
 *
 * @since 14.0
 * @author Colin Decker
 */
@J2ktIncompatible
@GwtIncompatible
public abstract class CharSource {

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

  /**
   * Returns a {@link ByteSource} view of this char source that encodes chars read from this source
   * as bytes using the given {@link Charset}.
   *

 *
 * @since 14.0
 * @author Colin Decker
 */
@J2ktIncompatible
@GwtIncompatible
public abstract class CharSink {

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

  /**
   * Opens a new {@link Writer} for writing to this sink. This method returns a new, independent
   * writer each time it is called.
   *

      return null;
    }
    return escapeUnsafe(c);
  }

  /**
   * Escapes a {@code char} value that has no direct explicit value in the replacement array and
   * lies outside the stated safe range. Subclasses should override this method to provide
   * generalized escaping for characters.
   *
   * <p>Note that arrays returned by this method must not be modified once they have been returned.

      @SuppressWarnings("unchecked")
      @Override
      <K extends K0, V extends @Nullable Object> Map<K, Collection<V>> createMap() {
        // K must actually be K0, since enums are effectively final
        // (their subclasses are inaccessible)
        return (Map<K, Collection<V>>) new EnumMap<K0, Collection<V>>(keyClass);
      }
    };
  }

  private static final class ArrayListSupplier<V extends @Nullable Object>

And these models are all sharing a lot of the data and duplicating attribute names and types.

We could do better.

We can declare a `UserBase` model that serves as a base for our other models. And then we can make subclasses of that model that inherit its attributes (type declarations, validation, etc).

All the data conversion, validation, documentation, etc. will still work as normally.

* `lt`: menor que (`l`ess `t`han)
* `le`: menor que ou igual (`l`ess than or `e`qual)

/// info | Informação

`Query`, `Path` e outras classes que você verá depois são subclasses de uma classe comum `Param`.

Todas elas compartilham os mesmos parâmetros para validação adicional e metadados que você viu.

///

/// note | Detalhes Técnicos

 * }
 *
 * @author Charles Fry
 * @since 10.0
 */
@GwtCompatible
public abstract class CacheLoader<K, V> {
  /** Constructor for use by subclasses. */
  protected CacheLoader() {}

  /**
   * Computes or retrieves the value corresponding to {@code key}.
   *
   * @param key the non-null key whose value should be loaded

 *
 * <p>The methods implemented in this class should not be overridden unless the subclass admits a
 * more efficient implementation.
 *
 * @author James Sexton
 * @param <N> Node parameter type
 * @param <E> Edge parameter type
 * @since 20.0
 */
@Beta
public abstract class AbstractNetwork<N, E> implements Network<N, E> {
  /** Constructor for use by subclasses. */
  public AbstractNetwork() {}

  @Override