Prepare the Account service

You will update the Account service that you built in the previous module to add some new endpoints to perform deposits and withdrawals. These new endpoints will be LRA participants.

1. Add new dependencies to the Maven POM

   Open the pom.xml in your accounts project and add these new dependency to the list. It will add support for the LRA client libraries.

     <dependency>
       <groupId>com.oracle.microtx.lra</groupId>
       <artifactId>microtx-lra-spring-boot-starter</artifactId>
       <version>24.2.1</version>
     </dependency>

2. Update the Spring Boot application configuration file

   Update your Account service’s Spring Boot configuration file, application.yaml in src/main/resources. Add a new lra section with the URL for the LRA coordinator. The URL shown here is for the Oracle Transaction Manager for Microservices that was installed as part of the Oracle Backend for Microservices and AI. Note: This URL is from the point of view of a service running it the same Kubernetes cluster.

     microtx:
       lra:
         coordinator-url: ${MP_LRA_COORDINATOR_URL}
         propagation-active: true
         headers-propagation-prefix: "{x-b3-, oracle-tmm-, authorization, refresh-}"   

3. Check the Journal repository and model

   Create a new Java file called Journal.java in src/main/com/example/accounts/model to define the model for the journal table. There are no new concepts in this class, so here is the code:

   package com.example.accounts.model;
   
   import jakarta.persistence.Column;
   import jakarta.persistence.Entity;
   import jakarta.persistence.GeneratedValue;
   import jakarta.persistence.GenerationType;
   import jakarta.persistence.Id;
   import jakarta.persistence.Table;
   
   import lombok.Data;
   import lombok.NoArgsConstructor;
   
   @Entity
   @Table(name = "JOURNAL")
   @Data
   @NoArgsConstructor
   public class Journal {
   
       @Id
       @GeneratedValue(strategy = GenerationType.IDENTITY)
       @Column(name = "JOURNAL_ID")
       private long journalId;
   
       // type is withdraw or deposit
       @Column(name = "JOURNAL_TYPE")
       private String journalType;
   
       @Column(name = "ACCOUNT_ID")
       private long accountId;
   
       @Column(name = "LRA_ID")
       private String lraId;
   
       @Column(name = "LRA_STATE")
       private String lraState;
   
       @Column(name = "JOURNAL_AMOUNT")
       private long journalAmount;
   
       public Journal(String journalType, long accountId, long journalAmount) {
         this.journalType = journalType;
         this.accountId = accountId;
         this.journalAmount = journalAmount;
       }
   
       public Journal(String journalType, long accountId, long journalAmount, String lraId, String lraState) {
         this.journalType = journalType;
         this.accountId = accountId;
         this.lraId = lraId;
         this.lraState = lraState;
         this.journalAmount = journalAmount;
       }
   }

   Open the file called JournalRepository.java in src/main/java/com/example/accounts/repository and add one JPA method findJournalByLraIdAndJournalType() to the interface. Here is the code:

   package com.example.accounts.repository;
   
   import java.util.List;
   
   import org.springframework.data.jpa.repository.JpaRepository;
   
   import com.example.accounts.model.Journal;
   
   public interface JournalRepository extends JpaRepository<Journal, Long> {
     List<Journal> findJournalByAccountId(long accountId);
   
     Journal findJournalByLraIdAndJournalType(String lraId, String journalType);
   }

   That completes the JPA configuration.