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
   *
   *    https://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.cayenne.lifecycle.relationship;
  
  import org.apache.cayenne.Persistent;
  import org.apache.cayenne.lifecycle.id.IdCoder;
  
  /**
   * @since 3.1
   */
  public class ObjectIdRelationshipHandler {
  
      protected IdCoder referenceableHandler;
  
      public ObjectIdRelationshipHandler(IdCoder referenceableHandler) {
          this.referenceableHandler = referenceableHandler;
      }
  
      public String objectIdRelationshipName(String uuidPropertyName) {
          return "cay:related:" + uuidPropertyName;
      }
  
      public String objectIdPropertyName(Persistent object) {
  
          ObjectIdRelationship annotation = object.getClass().getAnnotation(
                  ObjectIdRelationship.class);
  
          if (annotation == null) {
              throw new IllegalArgumentException(
                      "Object class is not annotated with @UuidRelationship: "
                              + object.getClass().getName());
          }
  
          // TODO: I guess we'll need to cache this metadata for performance if we are to support inheritance lookups, etc.
          return annotation.value();
      }
  
      /**
       * Establishes an ObjectId relationship between two objects. Objects must be
       * registered in the same ObjectContext. "from" argument is the object annotated with
       * UuidRelationship. Second argument can optionally be null.
       */
      public void relate(Persistent from, Persistent to) {
  
          if (from.getObjectContext() == null) {
              throw new IllegalArgumentException("'from' has null ObjectContext");
          }
  
          String property = objectIdPropertyName(from);
          String relationship = objectIdRelationshipName(property);
  
          if (to != null) {
              if (to.getObjectContext() == null) {
                  throw new IllegalArgumentException("'to' has null ObjectContext");
              }
  
              if (from.getObjectContext() != to.getObjectContext()) {
                  throw new IllegalArgumentException(
                          "'from' and 'to' objects are registered in different ObjectContexts");
              }
  
              from.writePropertyDirectly(relationship, to);
  
              if (to.getObjectId().isTemporary()
                      && !to.getObjectId().isReplacementIdAttached()) {
  
                  // defer ObjectId resolving till commit
                  from.writeProperty(property, new ObjectIdPropagatedValueFactory(
                          referenceableHandler,
                          to));
              }
              else {
                  String uuid = referenceableHandler.getStringId(to);
                  from.writeProperty(property, uuid);
              }
          }
          else {
              from.writeProperty(property, null);
              from.writePropertyDirectly(relationship, null);
          }
      }
  }
  