Monday 29 November 2021

Spring Data: ArangoDB: events

Spring Data ArangoDB supports several ApplicationEvent events. You can register to these events in your application and respond accordingly.

 

How to listen on events?

It is very simple, create a spring bean by extending AbstractArangoEventListener class.

@Component
public class EmployeeListener extends AbstractArangoEventListener<Employee> {
  public void onBeforeSave(final BeforeSaveEvent<Employee> event) {
    System.out.println("Before saving : " + event.getSource());
  }

  public void onAfterSave(final AfterSaveEvent<Employee> event) {
    System.out.println("After saving : " + event.getSource());
  }

  public void onBeforeDelete(final BeforeDeleteEvent<Employee> event) {
    System.out.println("Before deleting : " + event.getSource());
  }

  public void onAfterDelete(final AfterDeleteEvent<Employee> event) {
    System.out.println("After deleting : " + event.getSource());
  }

}

 

Find the below working application.

 

Step 1: Create new maven project ‘event-demo’.

 

Step 2: Update pom.xml with maven dependencies.

 

pom.xml

 

<project xmlns="http://maven.apache.org/POM/4.0.0"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.sample.app</groupId>
  <artifactId>event-demo</artifactId>
  <version>1</version>

  <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-parent -->
  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.4.5</version>
  </parent>


  <dependencies>
    <dependency>
      <groupId>com.arangodb</groupId>
      <artifactId>arangodb-spring-boot-starter</artifactId>
      <version>2.3.3.RELEASE</version>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
      </plugin>
    </plugins>
  </build>

</project>

 

Step 3: Define Employee entity class.

 

Employee.java

package com.sample.app.entity;

import com.arangodb.springframework.annotation.ArangoId;
import com.arangodb.springframework.annotation.Document;
import com.arangodb.springframework.annotation.PersistentIndex;

import org.springframework.data.annotation.Id;

@Document("employees")
@PersistentIndex(fields = { "age" })
public class Employee {

  @Id // db document field: _key
  private String key;

  @ArangoId // db document field: _id
  private String arangoId;

  private Integer id;
  private String firstName;
  private String lastName;
  private Integer age;

  public Employee() {

  }

  public Employee(Integer id, String firstName, String lastName, Integer age) {
    super();
    this.id = id;
    this.firstName = firstName;
    this.lastName = lastName;
    this.age = age;
  }

  public String getKey() {
    return key;
  }

  public void setKey(String key) {
    this.key = key;
  }

  public String getArangoId() {
    return arangoId;
  }

  public void setArangoId(String arangoId) {
    this.arangoId = arangoId;
  }

  public Integer getId() {
    return id;
  }

  public void setId(Integer id) {
    this.id = id;
  }

  public String getFirstName() {
    return firstName;
  }

  public void setFirstName(String firstName) {
    this.firstName = firstName;
  }

  public String getLastName() {
    return lastName;
  }

  public void setLastName(String lastName) {
    this.lastName = lastName;
  }

  public Integer getAge() {
    return age;
  }

  public void setAge(Integer age) {
    this.age = age;
  }

  @Override
  public String toString() {
    return "Employee [key=" + key + ", arangoId=" + arangoId + ", id=" + id + ", firstName=" + firstName
        + ", lastName=" + lastName + ", age=" + age + "]";
  }

}

 

Step 4: Define Employee repository interface.

 

EmployeeRepository.java

package com.sample.app.repository;

import com.arangodb.springframework.repository.ArangoRepository;
import com.sample.app.entity.Employee;

public interface EmployeeRepository extends ArangoRepository<Employee, String> {

}

 

Step 5: Define arango db configuration class.

 

ArangoConfig.java

package com.sample.app.config;

import org.springframework.context.annotation.Configuration;

import com.arangodb.ArangoDB;
import com.arangodb.springframework.annotation.EnableArangoRepositories;
import com.arangodb.springframework.config.ArangoConfiguration;

@Configuration
@EnableArangoRepositories(basePackages = { "com.sample.app" })
public class ArangoConfig implements ArangoConfiguration {

  @Override
  public ArangoDB.Builder arango() {
    return new ArangoDB.Builder().host("localhost", 8529).user("root").password("tiger");
  }

  @Override
  public String database() {
    return "abc_org";
  }
}

Step 6: Define EmployeeListener bean.

 

EmployeeListener.java

package com.sample.app.listener;

import org.springframework.stereotype.Component;

import com.arangodb.springframework.core.mapping.event.AbstractArangoEventListener;
import com.arangodb.springframework.core.mapping.event.AfterDeleteEvent;
import com.arangodb.springframework.core.mapping.event.AfterSaveEvent;
import com.arangodb.springframework.core.mapping.event.BeforeDeleteEvent;
import com.arangodb.springframework.core.mapping.event.BeforeSaveEvent;
import com.sample.app.entity.Employee;

@Component
public class EmployeeListener extends AbstractArangoEventListener<Employee> {
  public void onBeforeSave(final BeforeSaveEvent<Employee> event) {
    System.out.println("Before saving : " + event.getSource());
  }

  public void onAfterSave(final AfterSaveEvent<Employee> event) {
    System.out.println("After saving : " + event.getSource());
  }

  public void onBeforeDelete(final BeforeDeleteEvent<Employee> event) {
    System.out.println("Before deleting : " + event.getSource());
  }

  public void onAfterDelete(final AfterDeleteEvent<Employee> event) {
    System.out.println("After deleting : " + event.getSource());
  }

}

Step 7: Define main application class.

 

App.java

package com.sample.app;

import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;

import com.sample.app.entity.Employee;
import com.sample.app.repository.EmployeeRepository;

@SpringBootApplication
public class App {
  public static void main(String args[]) {
    SpringApplication.run(App.class, args);
  }

  @Bean
  public CommandLineRunner demo(EmployeeRepository employeeRepo) {

    return (args) -> {
      Employee emp1 = new Employee(1, "Ram", "Gurram", 31);

      System.out.println("Saving employee");
      emp1 = employeeRepo.save(emp1);
      
      System.out.println("\nDeleting employee");
      employeeRepo.deleteById(emp1.getArangoId());
    };
  }
}

Total project structure looks like below.



Run App.java, you will see below messages in console.

Saving employee
Before saving : Employee [key=null, arangoId=null, id=1, firstName=Ram, lastName=Gurram, age=31]
After saving : Employee [key=4098, arangoId=employees/4098, id=1, firstName=Ram, lastName=Gurram, age=31]

Deleting employee
Before deleting : employees/4098
After deleting : employees/4098

You can download complete working application from below link.

https://github.com/harikrishna553/springboot/tree/master/arangodb/event-demo




 

 

 

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