java8 classic code optimization example

 

public boolean changeEmployeeProject(ChangeEmployeeProjectPayload changeEmployeeProjectPayload) {
    List<EmployeesProjectRowMapper> employeesProjectRowMappers = employeeDao.fetchEmployeeProjectAssignment(changeEmployeeProjectPayload.getEmployee_ids());
    if (!employeesProjectRowMappers.isEmpty()) {
        Map<Integer, List<EmployeesProjectRowMapper>> employeeWithProjects = employeesProjectRowMappers.stream().collect(Collectors.groupingBy(e -> e.getEmployee_id()));
        Map<Integer, List<Integer>> employeeWithProject = new HashMap<>();
        employeeWithProjects.entrySet().stream().forEach(emp -> {
            employeeWithProject.put(emp.getKey(), emp.getValue().stream().map(e -> e.getProject_id()).collect(Collectors.toList()));
        });
        System.out.println("code---" + employeeWithProjects);
        System.out.println("pawan----" + employeeWithProject);
    }


    if (!employeesProjectRowMappers.isEmpty()) {
        Map<Integer, List<Integer>> employeeWithProject = employeesProjectRowMappers.stream()
                .collect(Collectors.groupingBy(
                        EmployeesProjectRowMapper::getEmployee_id,
                        Collectors.mapping(EmployeesProjectRowMapper::getProject_id, Collectors.toList())
                ));

        System.out.println("employeeWithProjects: " + employeeWithProject);
    }

    return true;
}