content: /*
   *  Licensed to the Apache Software Foundation (ASF) under one
   *  or more contributor license agreements.  See the NOTICE file
   *  distributed with this work for additional information
   *  regarding copyright ownership.  The ASF licenses this file
   *  to you under the Apache License, Version 2.0 (the
   *  "License"); you may not use this file except in compliance
   *  with the License.  You may obtain a copy of the License at
   *
   *        http://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing,
   *  software distributed under the License is distributed on an
   *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   *  KIND, either express or implied.  See the License for the
   *  specific language governing permissions and limitations
   *  under the License.
   */
  package org.apache.causeway.core.metamodel.object;
  
  import java.io.Serializable;
  import java.util.Optional;
  
  import org.apache.causeway.applib.services.bookmark.Bookmark;
  import org.apache.causeway.commons.internal.base._Casts;
  import org.apache.causeway.commons.internal.exceptions._Exceptions;
  import org.apache.causeway.core.metamodel.object.ManagedObject.Specialization.BookmarkPolicy;
  import org.apache.causeway.core.metamodel.objectmanager.ObjectManager;
  import org.apache.causeway.core.metamodel.objectmanager.memento.ObjectMemento;
  
  public interface Bookmarkable {
  
      BookmarkPolicy getBookmarkPolicy();
  
      default boolean isBookmarkSupported() {
          return !getBookmarkPolicy().isNoBookmark();
      }
  
      /**
       * Returns the object's bookmark as identified by the {@link ObjectManager}.
       * Bookmarks are immutable, hence will be memoized once fetched.
       */
      Optional<Bookmark> getBookmark();
  
      default Bookmark getBookmarkElseFail() {
          return getBookmark().orElseThrow(()->
                _Exceptions.unrecoverable("failed to bookmark %s", ((ManagedObject)this).objSpec()));
      }
  
      boolean isBookmarkMemoized();
  
      /**
       * If supports bookmark refreshing does so, otherwise acts identical to
       * {@link #getBookmark()}.
       */
      default Optional<Bookmark> refreshBookmark() {
          return _Casts.castTo(BookmarkRefreshable.class, this)
              .map(bookmarkRefreshable->{
                  bookmarkRefreshable.invalidateBookmark();
                  return bookmarkRefreshable.getBookmark();
              })
              .orElseGet(this::getBookmark);
      }
  
      /**
       * Optionally a {@link Serializable} representation of this object,
       *  with an additional memorized object title, based on whether
       *  is supported and a {@link Bookmark} is available.
       */
      Optional<ObjectMemento> getMemento();
      default ObjectMemento getMementoElseFail() {
          return getMemento()
                  .orElseThrow(()->_Exceptions.illegalState("failed to create memento for %s", this));
      }
  
      // -- SPECIAL SUB INTERFACES
  
      /**
       * Implements {@link Bookmarkable} reflecting
       * {@link org.apache.causeway.core.metamodel.object.ManagedObject.Specialization.BookmarkPolicy#NO_BOOKMARK}
       */
      static interface NoBookmark extends Bookmarkable {
          @Override default boolean isBookmarkSupported() { return false; }
          @Override default Optional<Bookmark> getBookmark() { return Optional.empty(); }
          @Override default boolean isBookmarkMemoized() { return false; }
          @Override default Optional<ObjectMemento> getMemento() { return Optional.empty(); }
      }
  
      static interface BookmarkRefreshable extends Bookmarkable {
          /**
           * Invalidates any memoized {@link Bookmark} for (lazy) recreation,
           * reflecting the object's current state.
           * @apiNote only makes sense in the context of (mutable) viewmodels
           */
          void invalidateBookmark();
      }
  
  }
  