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.services.xactn;
  
  import java.util.UUID;
  
  import org.apache.causeway.applib.mixins.system.HasInteractionIdAndSequence;
  
  /**
   * Value type used to identify a transaction within the context of an
   * outer {@link org.apache.causeway.applib.services.iactn.Interaction}.
   * <p>
   * The transaction and
   * {@link org.apache.causeway.applib.services.iactn.Interaction} are associated
   * by the {@link #getInteractionId() uniqueId}.
   * <p>
   * Obtainable from {@link TransactionService#currentTransactionId()}.
   *
   * @since 2.0 {@index}
   */
  public record TransactionId(
      /**
       * The unique identifier of the outer
       * {@link org.apache.causeway.applib.services.iactn.Interaction}.
       * <p>
       * Together with {@link #getSequence()}, this makes up the
       * implementation of {@link HasInteractionIdAndSequence}
       */
      UUID interactionId,
  
      /**
       * Identifies the transaction (there could be multiple) within the
       * {@link org.apache.causeway.applib.services.iactn.Interaction}.
       * <p>
       * Together with {@link #getInteractionId()}, this makes up the
       * implementation of {@link HasInteractionIdAndSequence}
       */
      int sequence,
  
      /**
       * Identifies the persistence context that this {@link TransactionId} was
       * created for.
       * <p>
       * Useful when there are multiple persistence contexts configured.
       * There are no constraints to format of this String, it is  left for the
       * implementation to ensure that the string is a unique identifier to
       * the context.
       */
      String context
      ) implements HasInteractionIdAndSequence {
  
      // -- EMPTY
  
      private static final TransactionId EMPTY =
              new TransactionId(UUID.fromString("0000-00-00-00-000000"), 0, "");
  
      /**
       * Factory method that returns a nominally &quot;empty&quot; transaction
       * identifier, used as a placeholder.
       */
      public static TransactionId empty() {
          return EMPTY;
      }
      
      @Override public UUID getInteractionId() { return interactionId; }
      @Override public int getSequence() { return sequence; }
  
  
  }
  