How to create a set of user defined types using spring data cassandra? - spring-boot

Question

I am using Spring Data Cassandra 1.5.8.RELEASE to connect with my cassandra db 3.11.2.
I tried creating #Table pojo with a Set as a column field but it is throwing the following errors:
user defined type not found, and
some other cassandra mapping exceptions.
Can somebody help me in data modeling an 'Employee' table having a column that represents a set of Department UDTs? (Using spring boot, spring data cassandra 1.5.8+ and Apache cassandra 3.11.2+)

Answer 1

Firstly, my main problem was with CassandraConfig.java, where I was un-necessarily overriding certain methods, where as the default implementation itself was more than enough.
Here, I am posting my complete solution for the benefit of those who are trying this use-case for the very first time.
Project Folder Structure:
Step 1: Creating cassandra data models:
CREATE KEYSPACE cassandra_sample
WITH replication = {'class':'SimpleStrategy', 'replication_factor' : 3};
CREATE TYPE dept_details (
dept_name text,
dept_address text
);
CREATE TABLE emp_details (
emp_id int PRIMARY KEY,
emp_name text,
emp_designation text,
dept_info set<frozen<dept_details>>
);
Step 2: 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.cassandra.sample</groupId>
<artifactId>spring-data-cassandra-sample</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>SpringDataCassandraSample</name>
<description>SpringDataCassandraSample</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.8.RELEASE</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-cassandra</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<properties>
<java.version>1.8</java.version>
</properties>
</project>
Step 3: Application.java
package com;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
#SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
Step 4: application.properties
# ===============================
# == DATA SOURCE
# ===============================
spring.data.cassandra.keyspace-name=cassandra_sample
spring.data.cassandra.contact-points=localhost
spring.data.cassandra.port=9042
spring.data.cassandra.schema-action=create_if_not_exists
Step 5: CassandraConfig.java
package com.cassandra.config;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.cassandra.config.java.AbstractCassandraConfiguration;
/**
* Created by jt on 10/6/17.
*/
#Configuration
public class CassandraConfig extends AbstractCassandraConfiguration {
#Value("${spring.data.cassandra.keyspace-name}")
private String keyspaceName;
#Override
protected String getKeyspaceName() {
return keyspaceName;
}
}
Step 6: Department.java
package com.cassandra.sample.domain;
import org.springframework.data.cassandra.mapping.Column;
import org.springframework.data.cassandra.mapping.UserDefinedType;
#UserDefinedType("dept_details")
public class Department {
#Column("dept_name")
private String departmentName;
#Column("dept_address")
private String departmentAddress;
public String getDepartmentName() {
return departmentName;
}
public void setDepartmentName(String departmentName) {
this.departmentName = departmentName;
}
public String getDepartmentAddress() {
return departmentAddress;
}
public void setDepartmentAddress(String departmentAddress) {
this.departmentAddress = departmentAddress;
}
#Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((departmentAddress == null) ? 0 : departmentAddress.hashCode());
result = prime * result + ((departmentName == null) ? 0 : departmentName.hashCode());
return result;
}
#Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
Department other = (Department) obj;
if (departmentAddress == null) {
if (other.departmentAddress != null)
return false;
} else if (!departmentAddress.equals(other.departmentAddress))
return false;
if (departmentName == null) {
if (other.departmentName != null)
return false;
} else if (!departmentName.equals(other.departmentName))
return false;
return true;
}
}
Step 7: Employee.java
package com.cassandra.sample.domain;
import java.util.Set;
import org.springframework.data.cassandra.mapping.Column;
import org.springframework.data.cassandra.mapping.PrimaryKey;
import org.springframework.data.cassandra.mapping.Table;
#Table("emp_details")
public class Employee {
#PrimaryKey("emp_id")
private int employeeId;
#Column("emp_name")
private String employeeName;
#Column("emp_designation")
private String designation;
#Column("dept_info")
private Set<Department> departmentDetails;
public int getEmployeeId() {
return employeeId;
}
public void setEmployeeId(int employeeId) {
this.employeeId = employeeId;
}
public String getEmployeeName() {
return employeeName;
}
public void setEmployeeName(String employeeName) {
this.employeeName = employeeName;
}
public String getDesignation() {
return designation;
}
public void setDesignation(String designation) {
this.designation = designation;
}
public Set<Department> getDepartmentDetails() {
return departmentDetails;
}
public void setDepartmentDetails(Set<Department> departmentDetails) {
this.departmentDetails = departmentDetails;
}
}
Step 8: EmployeeRepository.java
package com.cassandra.sample.repository;
import org.springframework.data.cassandra.repository.CassandraRepository;
import com.cassandra.sample.domain.Employee;
public interface EmployeeRepository extends CassandraRepository<Employee> {
Employee findByEmployeeId(int employeeId);
void deleteByEmployeeId(Integer employeeId, Class<Employee> employee) ;
}
Step 9: EmployeeRepositoryTest.java
package com.cassandra.sample.repository;
import java.util.HashSet;
import java.util.Set;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import com.cassandra.sample.domain.Department;
import com.cassandra.sample.domain.Employee;
#RunWith(SpringJUnit4ClassRunner.class)
#SpringBootTest
public class EmployeeRepositoryTest {
#Autowired
private EmployeeRepository employeeRepository;
// Note: Comment or UnComment the test methods as per the db-operation you are performing
/*#Test
public void insertEmployee(){
Employee employee = prepareEmployee();
employeeRepository.save(employee);
}*/
#Test
public void retrieveEmployee(){
Iterable<Employee> employees=employeeRepository.findAll();
for(Employee emp:employees){
System.out.println("Employee name :"+emp.getEmployeeName());
Set<Department> departments=emp.getDepartmentDetails();
for(Department dept:departments){
System.out.println("Department Name :"+dept.getDepartmentName());
}
}
}
/*#Test
public void updateEmployee(){
Employee employee=employeeRepository.findByEmployeeId(421);
employee.setEmployeeName("Test Employee Updated");
employee.setDesignation("SSE");
Set<Department> departments=employee.getDepartmentDetails();
Department department1=new Department();
department1.setDepartmentName("Civil");
department1.setDepartmentAddress("Test Dept Addr 3");
departments.add(department1);
employee.setDepartmentDetails(departments);
employeeRepository.save(employee);
}*/
/*#Test
public void deleteEmployee(){
employeeRepository.delete(employeeRepository.findByEmployeeId(421));
}*/
private Employee prepareEmployee() {
Set<Department> departments = prepareDepartments();
Employee employee=new Employee();
employee.setEmployeeId(421);
employee.setEmployeeName("Test Employee");
employee.setDesignation("Tech Lead");
employee.setDepartmentDetails(departments);
return employee;
}
private Set<Department> prepareDepartments() {
Set<Department> departments=new HashSet<>();
Department department1=new Department();
department1.setDepartmentName("EEE");
department1.setDepartmentAddress("Test Dept Addr 1");
departments.add(department1);
Department department2=new Department();
department2.setDepartmentName("CSE");
department2.setDepartmentAddress("Test Dept Addr 2");
departments.add(department2);
return departments;
}
}