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.facets.object.navchild;
  
  import java.lang.invoke.MethodHandle;
  import java.util.Optional;
  
  import org.apache.causeway.applib.graph.tree.TreeAdapter;
  import org.apache.causeway.commons.collections.Can;
  import org.apache.causeway.core.metamodel.facetapi.Facet;
  import org.apache.causeway.core.metamodel.facetapi.FacetHolder;
  import org.apache.causeway.core.metamodel.util.DeweyOrderComparator;
  
  /**
   * Provides the parent/child relationship information between pojos
   * to derive a tree-structure.
   *
   * @since 3.2
   */
  public sealed interface NavigableSubtreeFacet 
  extends Facet, TreeAdapter<Object>
  permits NavigableSubtreeFacetRecord {
      
      // -- FACTORY
      
      static <T> Optional<NavigableSubtreeFacet> create(
          final Can<NavigableSubtreeSequenceFacet> navigableSubtreeSequenceFacets,
          final FacetHolder facetHolder) {
          if(navigableSubtreeSequenceFacets.isEmpty()) return Optional.empty();
          
          var comparator = new DeweyOrderComparator();
          Can<MethodHandle> subNodesMethodHandles = navigableSubtreeSequenceFacets
              .sorted((a, b)->comparator.compare(a.sequence(), b.sequence()))
              .map(NavigableSubtreeSequenceFacet::methodHandle);
          
          return Optional.of(new NavigableSubtreeFacetRecord(subNodesMethodHandles, facetHolder));
      }
      
  }
  