Adds Employee, Project and ProjectAssignment

src/main/java/dgpena/siexample/persistence/Department.java

 package dgpena.siexample.persistence;
 
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+
 import javax.persistence.Entity;
 import javax.persistence.GeneratedValue;
 import javax.persistence.GenerationType;
 import javax.persistence.Id;
+import javax.persistence.OneToMany;
 
 @Entity
 public class Department {
@@ -14,6 +19,9 @@ public class Department {
 
 	private String name;
 	
+	@OneToMany(mappedBy="department")
+	private Set<Employee> employees = new HashSet<Employee>();
+	
 	public int getId() {
 		return id;
 	}
@@ -25,4 +33,24 @@ public class Department {
 	public void setName(String name) {
 		this.name = name;
 	}
+	
+	public Set<Employee> getEmployees() {
+		return Collections.unmodifiableSet(employees);
+	}
+	
+	public void addEmployee(Employee e) {
+		e.setDepartment(this);
+	}
+	
+	public void removeEmployee(Employee e) {
+		e.setDepartment(null);
+	}
+	
+	void internalAddEmployee(Employee e) {
+		this.employees.add(e);
+	}
+	
+	void internalRemoveEmployee(Employee e) {
+		this.employees.remove(e);
+	}
 }

src/main/java/dgpena/siexample/persistence/Departments.java

@@ -21,6 +21,10 @@ public class Departments {
 	}
 
 	public void deleteDepartment(Department d) {
+		// remove first my employees
+		for (Employee e: d.getEmployees()) {
+			e.setDepartment(null);
+		}
 		em.remove(d);
 	}
 

src/main/java/dgpena/siexample/persistence/Employee.java

+package dgpena.siexample.persistence;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+import javax.persistence.ManyToOne;
+
+@Entity
+public class Employee {
+
+	@Id
+	@GeneratedValue(strategy=GenerationType.IDENTITY)
+	private int id;
+
+	private String name;
+	
+	@ManyToOne
+	private Department department;
+	
+	public int getId() {
+		return id;
+	}
+	
+	public String getName() {
+		return name;
+	}
+	
+	public void setName(String name) {
+		this.name = name;
+	}
+	
+	public Department getDepartment() {
+		return department;
+	}
+	
+	public void setDepartment(Department department) {
+		if (this.department != null) {
+			this.department.internalRemoveEmployee(this);
+		}
+		
+		this.department = department;
+		
+		if (this.department != null) {
+			department.internalAddEmployee(this);
+		}
+	}
+	
+}

src/main/java/dgpena/siexample/persistence/Employees.java

+package dgpena.siexample.persistence;
+
+import javax.persistence.EntityManager;
+
+public class Employees {
+
+	private EntityManager em;
+	
+	public Employees(EntityManager em) {
+		this.em = em;
+	}
+	
+	public void addNewEmployee(Employee e) {
+		this.em.persist(e);
+	}
+	
+}

src/main/java/dgpena/siexample/persistence/Project.java

+package dgpena.siexample.persistence;
+
+import java.util.HashSet;
+import java.util.Set;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+import javax.persistence.OneToMany;
+
+@Entity
+public class Project {
+	
+	@Id
+	@GeneratedValue(strategy=GenerationType.IDENTITY)
+	private int id;
+	
+	private String name;
+	
+	@OneToMany(mappedBy="project")
+	private Set<ProjectAssignment> projectAssignments = new HashSet<>();
+	
+	public int getId() {
+		return id;
+	}
+	
+	public String getName() {
+		return name;
+	}
+	
+	public void setName(String name) {
+		this.name = name;
+	}
+	
+	public Set<Employee> getEmployees() {
+		Set<Employee> employees = new HashSet<>();
+		
+		for (ProjectAssignment pa : projectAssignments) {
+			employees.add(pa.getEmployee());
+		}
+		
+		return employees;
+	}
+
+	void internalRemoveProjectAssignment(ProjectAssignment projectAssignment) {
+		this.projectAssignments.remove(projectAssignment);
+		
+	}
+
+	void internalAddProjectAssignment(ProjectAssignment projectAssignment) {
+		this.projectAssignments.add(projectAssignment);
+		
+	}
+	
+}

src/main/java/dgpena/siexample/persistence/ProjectAssignment.java

+package dgpena.siexample.persistence;
+
+import java.io.Serializable;
+import java.util.Date;
+
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.IdClass;
+import javax.persistence.ManyToOne;
+
+@Entity
+@IdClass(ProjectAssignment.ProjectAssignmentId.class)
+public class ProjectAssignment {
+
+	@Id
+	@ManyToOne
+	private Project project;
+	
+	@Id
+	@ManyToOne
+	private Employee employee;
+	
+	
+	private Date startDate;
+	
+	
+	public Project getProject() {
+		return project;
+	}
+	
+	public Employee getEmployee() {
+		return employee;
+	}
+	
+	public void setProject(Project project) {
+		if (this.project != null) {
+			project.internalRemoveProjectAssignment(this);
+		}
+		this.project = project;
+		
+		if (this.project != null) {
+			this.project.internalAddProjectAssignment(this);
+		}
+		this.project = project;
+	}
+	
+	public void setEmployee(Employee employee) {
+		this.employee = employee;
+	}
+	
+	public Date getStartDate() {
+		return startDate;
+	}
+	
+	public void setStartDate(Date startDate) {
+		this.startDate = startDate;
+	}
+	
+	public static class ProjectAssignmentId implements Serializable {
+		private int project;
+		private int employee;
+		
+		
+		public ProjectAssignmentId() {}
+		public ProjectAssignmentId(int project, int employee) {
+			super();
+			this.project = project;
+			this.employee = employee;
+		}
+		@Override
+		public int hashCode() {
+			final int prime = 31;
+			int result = 1;
+			result = prime * result + employee;
+			result = prime * result + project;
+			return result;
+		}
+		@Override
+		public boolean equals(Object obj) {
+			if (this == obj)
+				return true;
+			if (obj == null)
+				return false;
+			if (getClass() != obj.getClass())
+				return false;
+			ProjectAssignmentId other = (ProjectAssignmentId) obj;
+			if (employee != other.employee)
+				return false;
+			if (project != other.project)
+				return false;
+			return true;
+		}
+		
+		
+	}
+	
+}

src/main/resources/META-INF/persistence.xml

@@ -4,7 +4,9 @@
 	version="2.0">
 	<persistence-unit name="si-database" transaction-type="RESOURCE_LOCAL">
 		<class>dgpena.siexample.persistence.Department</class>
-		
+		<class>dgpena.siexample.persistence.Employee</class>
+		<class>dgpena.siexample.persistence.Project</class>
+		<class>dgpena.siexample.persistence.ProjectAssignment</class>
 		<properties>
 			<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
 			<property name="javax.persistence.jdbc.user" value="siuser" />

src/test/java/dgpena/siexample/persistence/DepartmentsTest.java

@@ -64,6 +64,28 @@ public class DepartmentsTest extends SQLBasedTest {
 		
 	}
 	
+	@Test
+	public void testFindByIdWithEmployees() throws SQLException {
+		// insert a department previously with JDBC
+		Statement statement = jdbcConnection.createStatement();
+		statement.executeUpdate("INSERT INTO Department(name) values('finanzas')", Statement.RETURN_GENERATED_KEYS);
+		int deptId = getLastInsertedId(statement);
+		
+		// insert an employee in this department previously with JDBC
+		statement = jdbcConnection.createStatement();
+		statement.executeUpdate("INSERT INTO Employee(name, department_id) values('pepe', "+deptId+")", Statement.RETURN_GENERATED_KEYS);
+		int empId = getLastInsertedId(statement);
+		
+		EntityManager em = emf.createEntityManager();
+		Departments depts = new Departments(em);
+		Department d = depts.findById(deptId);
+		Set<Employee> departmentEmployees = d.getEmployees();
+		
+		assertEquals(1, departmentEmployees.size());
+		assertEquals(empId, departmentEmployees.iterator().next().getId());
+		
+	}
+	
 	@Test
 	public void testUpdateDepartment() throws SQLException {
 		// insert a department previously with JDBC
@@ -109,12 +131,44 @@ public class DepartmentsTest extends SQLBasedTest {
 		assertEquals(0, rs.getInt("total"));
 	}
 	
+	@Test
+	public void testDeleteDepartmentWithEmployees() throws SQLException {
+		// insert a department previously with JDBC
+		Statement statement = jdbcConnection.createStatement();
+		statement.executeUpdate("INSERT INTO Department(name) values('finanzas')", Statement.RETURN_GENERATED_KEYS);
+		int deptId = getLastInsertedId(statement);
+
+		// insert an employee in this department previously with JDBC
+		statement = jdbcConnection.createStatement();
+		statement.executeUpdate("INSERT INTO Employee(name, department_id) values('pepe', "+deptId+")", Statement.RETURN_GENERATED_KEYS);
+		int empId = getLastInsertedId(statement);
+				
+		EntityManager em = emf.createEntityManager();
+		Departments depts = new Departments(em);
+		Department d = depts.findById(deptId);
+		
+		em.getTransaction().begin();
+			depts.deleteDepartment(d);
+		em.getTransaction().commit();
+		
+		// check in the DB using JDBC
+		statement = jdbcConnection.createStatement();
+		ResultSet rs = statement.executeQuery("SELECT COUNT(*) as total FROM Department d where d.id = "+deptId);
+		rs.next();
+		assertEquals(0, rs.getInt("total"));
+	}
+
+	
 	@Test
 	public void testFindAllDepartments() throws SQLException {
 		// insert a department previously with JDBC
 		Statement statement = jdbcConnection.createStatement();
+		
+		
+		statement.executeUpdate("UPDATE Employee set department_id = NULL WHERE department_id IS NOT NULL", Statement.RETURN_GENERATED_KEYS);
 		statement.executeUpdate("DELETE FROM Department", Statement.RETURN_GENERATED_KEYS);
 		
+		
 		statement = jdbcConnection.createStatement();
 		statement.executeUpdate("INSERT INTO Department(name) values('dept-1')", Statement.RETURN_GENERATED_KEYS);
 		

src/test/java/dgpena/siexample/persistence/EmployeesTest.java

+package dgpena.siexample.persistence;
+
+import static org.junit.Assert.*;
+
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Statement;
+
+import javax.persistence.EntityManager;
+import javax.persistence.EntityManagerFactory;
+import javax.persistence.Persistence;
+
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+public class EmployeesTest extends SQLBasedTest {
+
+private static EntityManagerFactory emf;
+	
+	@BeforeClass
+	public static void setUpEntityManagerFactory() {
+		emf = Persistence.createEntityManagerFactory("si-database");
+	}
+	
+	@Test
+	public void testAddNewEmployee() throws SQLException {
+		// insert a department previously with JDBC
+		Statement statement = jdbcConnection.createStatement();
+		statement.executeUpdate("INSERT INTO Department(name) values('finanzas')", Statement.RETURN_GENERATED_KEYS);
+		int deptId = getLastInsertedId(statement);
+				
+		EntityManager em = emf.createEntityManager();
+		
+		Departments depts = new Departments(em);
+		Department dept = depts.findById(deptId);
+		
+		Employee e = new Employee();
+		e.setName("pepe");
+		e.setDepartment(dept);
+		
+
+		Employees employees = new Employees(em);
+		
+		em.getTransaction().begin();
+		
+			employees.addNewEmployee(e);
+			
+			// ensure that bi-directional relation is always consistent
+			assertEquals(1, dept.getEmployees().size());
+			
+		em.getTransaction().commit();
+
+		int employeeId = e.getId();
+		
+		
+		statement = jdbcConnection.createStatement();
+		ResultSet res = statement.executeQuery("SELECT * from Employee where id = "+employeeId);
+		res.next();
+		assertEquals(deptId, res.getInt("department_id"));
+		assertEquals("pepe", res.getString("name"));
+		
+		
+	}
+	
+}

src/test/resources/META-INF/persistence.xml

@@ -4,6 +4,10 @@
 	version="2.0">
 	<persistence-unit name="si-database" transaction-type="RESOURCE_LOCAL">
 		<class>dgpena.siexample.persistence.Department</class>
+		<class>dgpena.siexample.persistence.Employee</class>
+		<class>dgpena.siexample.persistence.Project</class>
+		<class>dgpena.siexample.persistence.ProjectAssignment</class>		
+	
 		<properties>
 			<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
 			<property name="javax.persistence.jdbc.user" value="siuser" />