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Integration Project- Micro Services Migration Story with JBoss BPM Travel Agency - Part Four

Part Four- Persistence with JPA

In the post, I am going to show you how to create the fuse side travel agency demo from scratch. We are going to take a look at how create the Flight/Hotel booking and cancellation service. If you would like to know more about the micro service architecture this demo is trying to showcase, please go to part 2 of the series
for more information. Due to the fact that Flight and Hotel booking are identical, I will be focusing on the Hotel side. What this service does, is it simply books the hotel when receives a an ID when the booking is done, it'll return a 26 character BookingID as key. This key is then used if the user wants to cancel the booking. As for cancellation, it'll return the cost to cancel it, if the key provided is not found, it'll return 0, as nothing can be cancelled using the key provided.

All request to backend services in this demo are all async, so there are different message queue in the broker connecting to the promotion, booking and cancellation services. For booking service we are going to create an JPA entity contains the booking ID we have received from the process then store the entity to it's table. And in cancellation, it first check if the the booking id exists in the table, if yes, it'll calculate the fee and return it. If nothing found, then a constant number "zero" will return.



We need to first configure the two endpoints from message broker and database.
Like in normal JPA application, first we will need to identify our entities, in this case, we have two, booking entity and cancel booking entity.
package org.blogdemo.travelagency.hotelbookingservice;

import static javax.persistence.LockModeType.PESSIMISTIC_WRITE;

import java.util.Date;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.NamedQuery;
import javax.persistence.Table;

@Entity
@NamedQuery(name = "queryHotelBookingById", query = "select hotelbooking from Booking hotelbooking where hotelbooking.bookingid=:bookingid " , lockMode = PESSIMISTIC_WRITE)
@Table(name = "hotelbooking")
public class Booking { 
 @Column(name = "bookingid")
 @Id
 String bookingid;
 
 @Column(name = "recieveDate")
 Date recieveDate;

 public String getBookingid() {
  return bookingid;
 }

 public void setBookingid(String bookingid) {
  this.bookingid = bookingid;
 }

 public Date getRecieveDate() {
  return recieveDate;
 }

 public void setRecieveDate(Date recieveDate) {
  this.recieveDate = recieveDate;
 }

}


package org.blogdemo.travelagency.hotelbookingservice;
import java.util.Date;
import javax.persistence.*;
@Entity
@Table(name = "cancelhotelbooking")
public class CancelBooking {
 @Column(name = "bookingid")
 @Id
 String bookingid;
 
 @Column(name = "recieveDate")
 Date recieveDate;

 public String getBookingid() { bookingid;
 public void setBookingid(String bookingid) {
  this.bookingid = bookingid;
 }
 public Date getRecieveDate() { recieveDate;}
 public void setRecieveDate(Date recieveDate) {
  this.recieveDate = recieveDate;
 }
}


And then we need to set the datasource and bean information. Under resource/META-INF create a xml file called persistence.xml. This file contains the database setting, login authentication, and depend on the JPA library you use, there are minor difference when you want to configure the behavior of how it should sync with database. I am using OpenJPA this time.

  
    org.blogdemo.travelagency.hotelbookingservice.Booking
    org.blogdemo.travelagency.hotelbookingservice.CancelBooking
      
       
        
       
       
       
       
       
        
    

1. Meesage broker location and authentication

    
  
  



2. Entity and Transaction managers, and also the datasource setting like normal JPA applications     CAUTION,   
(In Fuse, it's best to use hibernate and Aries JTA.  I will migrate this project in Fuse 6.2)

  
  


  

   
  
  
    
  

 

For booking, because we need to insert a new entity, therefore create a service to handle the creation of the entity.And inside booking service it also handles all the necessary business logic such as generate random booking id and calculating the cancelation fee. Then we need to register the service bean And create the route to book hotel
Create route to cancel booking


Detail instructions are here:

 

For more detail side in BPM Suite, please click here to Eric Schabell's post.

Micro Services Migration Story with JBoss BPM Travel Agency

  Part One: Introduction and Installation
  Part Two: Moving towards Microservices
  Part Three: Retrieving Data with JDBC 
  Part Four: Persistence with JPA

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