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.runtimeservices.publish;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import jakarta.annotation.PostConstruct;
  import jakarta.annotation.Priority;
  import jakarta.inject.Inject;
  import jakarta.inject.Named;
  import jakarta.inject.Provider;
  
  import org.springframework.beans.factory.annotation.Qualifier;
  import org.jspecify.annotations.Nullable;
  import org.springframework.stereotype.Service;
  
  import org.apache.causeway.applib.annotation.PriorityPrecedence;
  import org.apache.causeway.applib.services.clock.ClockService;
  import org.apache.causeway.applib.services.iactnlayer.InteractionLayerTracker;
  import org.apache.causeway.applib.services.publishing.spi.EntityPropertyChange;
  import org.apache.causeway.applib.services.publishing.spi.EntityPropertyChangeSubscriber;
  import org.apache.causeway.applib.services.user.UserService;
  import org.apache.causeway.applib.services.xactn.TransactionId;
  import org.apache.causeway.applib.services.xactn.TransactionService;
  import org.apache.causeway.commons.collections.Can;
  import org.apache.causeway.commons.having.HasEnabling;
  import org.apache.causeway.core.config.CausewayConfiguration;
  import org.apache.causeway.core.metamodel.services.objectlifecycle.HasEnlistedEntityPropertyChanges;
  import org.apache.causeway.core.runtimeservices.CausewayModuleCoreRuntimeServices;
  import org.apache.causeway.core.security.util.XrayUtil;
  import org.apache.causeway.core.transaction.changetracking.EntityPropertyChangePublisher;
  
  import org.jspecify.annotations.NonNull;
  import lombok.RequiredArgsConstructor;
  import lombok.extern.log4j.Log4j2;
  
  /**
   * Default implementation of {@link EntityPropertyChangePublisher}.
   *
   * @since 2.0 {@index}
   */
  @Service
  @Named(CausewayModuleCoreRuntimeServices.NAMESPACE + ".EntityPropertyChangePublisherDefault")
  @Priority(PriorityPrecedence.EARLY)
  @Qualifier("Default")
  @RequiredArgsConstructor(onConstructor_ = {@Inject})
  @Log4j2
  public class EntityPropertyChangePublisherDefault implements EntityPropertyChangePublisher {
  
      private final List<EntityPropertyChangeSubscriber> subscribers;
      private final UserService userService;
      private final ClockService clockService;
      private final TransactionService transactionService;
      private final InteractionLayerTracker iaTracker;
      private final Provider<HasEnlistedEntityPropertyChanges> hasEnlistedEntityPropertyChangesProvider;
      private final CausewayConfiguration causewayConfiguration;
  
      private Can<EntityPropertyChangeSubscriber> enabledSubscribers = Can.empty();
  
      @PostConstruct
      public void init() {
          enabledSubscribers = Can.ofCollection(subscribers)
                  .filter(HasEnabling::isEnabled);
      }
  
      private HasEnlistedEntityPropertyChanges hasEnlistedEntityPropertyChanges() {
          return hasEnlistedEntityPropertyChangesProvider.get();
      }
  
      @Override
      public void publishChangedProperties() {
  
          transactionService.flushTransaction();
  
          if(enabledSubscribers.isEmpty()) {
              return;
          }
  
          var currentTime = clockService.getClock().nowAsJavaSqlTimestamp();
          var currentUser = userService.currentUserNameElseNobody();
          var currentTransactionId = transactionService.currentTransactionId().orElse(TransactionId.empty());
  
          var enlistedPropertyChanges = hasEnlistedEntityPropertyChanges().getPropertyChanges(
                  currentTime,
                  currentUser,
                  currentTransactionId);
          var duplicates = new ArrayList<EntityPropertyChange>();
          var uniquePropertyChanges = enlistedPropertyChanges
                  .toSet(duplicates::add) // ensure uniqueness
                  .stream()
                  .collect(Can.toCan());
          if(log.isWarnEnabled() && ! duplicates.isEmpty()) {
              log.warn("Duplicate enlisted property changes discovered\n{}", duplicates);
          }
  
          XrayUtil.SequenceHandle xrayHandle = null;
          try {
              xrayHandle = _Xray.enterEntityPropertyChangePublishing(
                      iaTracker,
                      uniquePropertyChanges,
                      enabledSubscribers,
                      () -> getCannotPublishReason(uniquePropertyChanges)
              );
  
              if (uniquePropertyChanges.size() <= causewayConfiguration.getCore().getRuntimeServices().getEntityPropertyChangePublisher().getBulk().getThreshold()) {
                  uniquePropertyChanges.forEach(propertyChange -> {
                      for (var subscriber : enabledSubscribers) {
                          subscriber.onChanging(propertyChange);
                      }
                  });
              } else {
                  for (var subscriber : enabledSubscribers) {
                      subscriber.onChanging(uniquePropertyChanges);
                  }
              }
          } finally {
              _Xray.exitPublishing(xrayHandle);
          }
      }
  
      // -- HELPER
  
      // x-ray support
      private @Nullable String getCannotPublishReason(final @NonNull Can<EntityPropertyChange> payload) {
          return enabledSubscribers.isEmpty()
                  ? "no subscribers"
                  : payload.isEmpty()
                          ? "no changes had been enlisted"
                          : null;
      }
  
  }
  