Refactor Play example

play-framework/student-api/app/controllers/AsyncController.java

@@ -1,13 +1,17 @@
 package controllers;
 
 import akka.actor.ActorSystem;
+
 import javax.inject.*;
+
 import play.*;
 import play.mvc.*;
+
 import java.util.concurrent.Executor;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.CompletionStage;
 import java.util.concurrent.TimeUnit;
+
 import scala.concurrent.duration.Duration;
 import scala.concurrent.ExecutionContextExecutor;
 
@@ -38,7 +42,7 @@ public class AsyncController extends Controller {
     /**
      * An action that returns a plain text message after a delay
      * of 1 second.
-     *
+     * <p>
      * The configuration in the <code>routes</code> file means that this method
      * will be called when the application receives a <code>GET</code> request with
      * a path of <code>/message</code>.

play-framework/student-api/app/controllers/StudentController.java

@@ -1,27 +1,33 @@
 package controllers;
-import models.*;
-import util.*;
-import play.mvc.*;
-import play.libs.Json;
-import play.libs.Json.*;
+
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
-import java.util.List;
+import models.Student;
+import models.StudentStore;
+import play.libs.Json;
+import play.mvc.Controller;
+import play.mvc.Result;
+import util.Util;
+
+import java.util.Set;
 
 public class StudentController extends Controller {
     public Result create() {
         JsonNode json = request().body().asJson();
-		if(json == null)
+        if (json == null) {
             return badRequest(Util.createResponse("Expecting Json data", false));
-		Student student=StudentStore.getInstance().addStudent((Student)Json.fromJson(json,Student.class));
+        }
+        Student student = StudentStore.getInstance().addStudent(Json.fromJson(json, Student.class));
         JsonNode jsonObject = Json.toJson(student);
         return created(Util.createResponse(jsonObject, true));
     }
+
     public Result update() {
         JsonNode json = request().body().asJson();
-		if(json == null)
+        if (json == null) {
             return badRequest(Util.createResponse("Expecting Json data", false));
-		Student student=StudentStore.getInstance().updateStudent((Student)Json.fromJson(json,Student.class));
+        }
+        Student student = StudentStore.getInstance().updateStudent(Json.fromJson(json, Student.class));
         if (student == null) {
             return notFound(Util.createResponse("Student not found", false));
         }
@@ -29,14 +35,15 @@ public class StudentController extends Controller {
         JsonNode jsonObject = Json.toJson(student);
         return ok(Util.createResponse(jsonObject, true));
     }
+
     public Result retrieve(int id) {
-		Student student=StudentStore.getInstance().getStudent(id);
-		if(student==null){
+        if (StudentStore.getInstance().getStudent(id) == null) {
             return notFound(Util.createResponse("Student with id:" + id + " not found", false));
         }
-		JsonNode jsonObjects=Json.toJson(student);
+        JsonNode jsonObjects = Json.toJson(StudentStore.getInstance().getStudent(id));
         return ok(Util.createResponse(jsonObjects, true));
     }
+
     public Result listStudents() {
         Set<Student> result = StudentStore.getInstance().getAllStudents();
         ObjectMapper mapper = new ObjectMapper();
@@ -45,9 +52,9 @@ public class StudentController extends Controller {
         return ok(Util.createResponse(jsonData, true));
 
     }
+
     public Result delete(int id) {
-		boolean status=StudentStore.getInstance().deleteStudent(id);
-		if(!status){
+        if (!StudentStore.getInstance().deleteStudent(id)) {
             return notFound(Util.createResponse("Student with id:" + id + " not found", false));
         }
         return ok(Util.createResponse("Student with id:" + id + " deleted", true));

play-framework/student-api/app/models/StudentStore.java

@@ -1,5 +1,5 @@
 package models;
-import java.util.ArrayList;
+
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
@@ -10,13 +10,14 @@ public class StudentStore {
     private Map<Integer, Student> students = new HashMap<>();
 
     public static StudentStore getInstance() {
-        if (instance == null)
+        if (instance == null) {
             instance = new StudentStore();
+        }
         return instance;
     }
 
     public Student addStudent(Student student) {
-        int id = students.size() + 1;
+        int id = students.size();
         student.setId(id);
         students.put(id, student);
         return student;

play-framework/student-api/app/util/Util.java

@@ -1,8 +1,8 @@
 package util;
+
+import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.node.ObjectNode;
 import play.libs.Json;
-import play.libs.Json.*;
-import com.fasterxml.jackson.databind.JsonNode;           
 
 public class Util {
     public static ObjectNode createResponse(Object response, boolean ok) {