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.applib.events.domain;
  
  import org.apache.causeway.applib.util.ObjectContracts;
  import org.apache.causeway.applib.util.ToString;
  
  import lombok.Getter;
  import lombok.Setter;
  
  /**
   * Fired whenever the framework interacts with a domain object's property.
   *
   * <p>
   * This is the specialization of {@link AbstractDomainEvent}, for properties,
   *  * which should then be further subclassed by domain application.
   * </p>
   *
   * <p>
   * The class has a number of responsibilities (in addition to those it
   * inherits):
   * </p>
   *
   * <ul>
   *     <li>
   *          capture the old and new values of the property
   *     </li>
   * </ul>
   *
   * <p>
   * The class itself is instantiated automatically by the framework using a
   * no-arg constructor; fields are set reflectively.
   * </p>
   *
   * @since 1.x {@index}
   */
  public abstract class PropertyDomainEvent<S,T> extends AbstractDomainEvent<S> {
  
      /**
       * This class is the default for the
       * {@link org.apache.causeway.applib.annotation.Property#domainEvent()}
       * annotation attribute.
       *
       * <p>
       * Whether this raises an event or not depends upon the
       * <tt>causeway.applib.annotation.property.domain-event.post-for-default</tt>
       * configuration property.
       * </p>
       */
      public static class Default extends PropertyDomainEvent<Object, Object> {}
  
      /**
       * Convenience class to use indicating that an event should <i>not</i> be
       * posted (irrespective of the configuration property setting for the
       * {@link Default} event.
       */
      public static class Noop extends PropertyDomainEvent<Object, Object> {}
  
      /**
       * Convenience class meaning that an event <i>should</i> be posted
       * (irrespective of the configuration property setting for the
       * {@link Default} event..
       */
      public static class Doop extends PropertyDomainEvent<Object, Object> {}
  
      /**
       * Subtypes can define a no-arg constructor; the framework sets state
       * via (non-API) setters.
       */
      public PropertyDomainEvent() {
      }
  
      /**
       * Subtypes can define a one-arg constructor; the framework sets state
       * via (non-API) setters.
       * <p>
       * A one-arg constructor is particularly useful in the context of non-static
       * DomainEvent class nesting.
       * @apiNote The Java compiler implicitly adds a constructor
       * to the non-static nested class, receiving the parent type as single argument.
       */
      public PropertyDomainEvent(final S source) {
          super(source);
      }
  
      /**
       * The current (pre-modification) value of the property.
       *
       * <p>
       * Populated at {@link org.apache.causeway.applib.events.domain.AbstractDomainEvent.Phase#VALIDATE} and subsequent
       * phases (but null for
       * {@link org.apache.causeway.applib.events.domain.AbstractDomainEvent.Phase#HIDE hidden}
       * and {@link org.apache.causeway.applib.events.domain.AbstractDomainEvent.Phase#DISABLE disable}
       * phases).
       * </p>
       */
      @Getter @Setter
      private T oldValue;
  
      /**
       * The proposed (post-modification) value of the property.
       *
       * <p>
       * Populated at
       * {@link org.apache.causeway.applib.events.domain.AbstractDomainEvent.Phase#VALIDATE}
       * and subsequent phases (but null for
       * {@link Phase#HIDE hidden}
       * and {@link org.apache.causeway.applib.events.domain.AbstractDomainEvent.Phase#DISABLE disable}
       * phases).
       * </p>
       *
       * <p>
       *     The proposed new value can also be modified by event handlers
       *     during the
       *     {@link org.apache.causeway.applib.events.domain.AbstractDomainEvent.Phase#EXECUTING executing}
       *     phase.  The new value must be the same type as the expected value;
       *     the framework performs no sanity checks.
       * </p>
       */
      @Getter @Setter
      private T newValue;
  
      private static final ToString<PropertyDomainEvent<?,?>> toString =
              ObjectContracts.<PropertyDomainEvent<?,?>>
      toString("source", PropertyDomainEvent::getSource)
      .thenToString("identifier", PropertyDomainEvent::getIdentifier)
      .thenToString("eventPhase", PropertyDomainEvent::getEventPhase)
      .thenToString("oldValue", PropertyDomainEvent::getOldValue)
      .thenToString("newValue", PropertyDomainEvent::getNewValue)
      ;
  
      @Override
      public String toString() {
          return toString.toString(this);
      }
  
  }
  