Last active
December 16, 2023 16:03
-
-
Save Obolrom/d6f367edc709a7dc5588d5839860f3dd to your computer and use it in GitHub Desktop.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| import java.util.Objects | |
| /** | |
| * Code sample for detecting objects duplication by given criteria | |
| * | |
| * The task: detect duplications by the following uniqueness criteria | |
| * | |
| * The criteria: | |
| * * firstName | |
| * * lastName | |
| * * at least one common company id (assume the company id is unique) | |
| */ | |
| data class Employee( | |
| val id: Long, | |
| val firstName: String, | |
| val lastName: String, | |
| val companies: List<Company>, | |
| val phoneNumber: String, | |
| ) { | |
| override fun toString(): String { | |
| return "{id=$id, firstName='$firstName', lastName='$lastName', companies=$companies, phoneNumber='$phoneNumber'}" | |
| } | |
| } | |
| data class Company( | |
| val id: Long, | |
| val name: String, | |
| ) { | |
| override fun toString(): String { | |
| return "{id=$id, name='$name'}" | |
| } | |
| } | |
| // sample duplication criteria, depends on your business rules | |
| data class EmployeeDuplicationCriteria( | |
| val firstName: String, | |
| val lastName: String, | |
| val companyIds: Set<Long>, | |
| ) { | |
| override fun equals(other: Any?): Boolean { | |
| if (this === other) return true | |
| if (javaClass != other?.javaClass) return false | |
| other as EmployeeDuplicationCriteria | |
| if (firstName != other.firstName) return false | |
| if (lastName != other.lastName) return false | |
| // check if at least on company id contains both employees -> duplication | |
| if (companyIds.intersect(other.companyIds).isEmpty()) return false | |
| return true | |
| } | |
| // do not use companyIds to avoid improper grouping | |
| override fun hashCode(): Int { | |
| return Objects.hash(firstName, lastName) | |
| } | |
| } | |
| fun main() { | |
| val companyA = Company(1, "CompanyA") | |
| val companyB = Company(2, "CompanyB") | |
| // duplicated employees: (1, 4), (3, 5) | |
| val employees = listOf( | |
| Employee(1, "John", "Patrick", listOf(companyA), "sampleNumber1"), | |
| Employee(2, "Jake", "Andretti", listOf(companyA), "sampleNumber2"), | |
| Employee(3, "Andrew", "Gray", listOf(companyB), "sampleNumber3"), | |
| Employee(4, "John", "Patrick", listOf(companyA, companyB), "sampleNumber4"), | |
| Employee(5, "Andrew", "Gray", listOf(companyB), "sampleNumber5"), | |
| ) | |
| // with map simply transform the employee list into list of Pair<EmployeeDuplicationCriteria, Employee> | |
| employees.map { employee -> | |
| EmployeeDuplicationCriteria( | |
| firstName = employee.firstName, | |
| lastName = employee.lastName, | |
| companyIds = employee.companies.mapTo(mutableSetOf()) { it.id }, | |
| ) to employee | |
| } | |
| // the magic happens here, we group by our custom criteria object | |
| .groupBy { (dupCriteria, _) -> dupCriteria} | |
| .map { (_, resultedDuplications) -> resultedDuplications.map { it.second } } | |
| .filter { it.size > 1 } | |
| .forEach { duplicatedEmployees -> | |
| println("duplicated employee ids: ${duplicatedEmployees.map { it.id }}, $duplicatedEmployees") | |
| } | |
| } |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment