3 major changes (#716)

* made changes to java reflection

* removed redundant method makeSound in Animal abstract class

* added project for play-framework article

* added project for regex

* changed regex project from own model to core-java

* added project for routing in play

* made changes to regex project

* refactored code for REST API with Play project

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

@@ -38,8 +38,8 @@ public class StudentController extends Controller {
         return ok(Util.createResponse(jsonObjects,true));
     }
 	public Result listStudents() {
-		List<Student> result=StudentStore.getInstance().getAllStudents();
-		    	ObjectMapper mapper = new ObjectMapper();
+		Set<Student> result=StudentStore.getInstance().getAllStudents();
+		ObjectMapper mapper = new ObjectMapper();
 
 		JsonNode jsonData=mapper.convertValue(result, JsonNode.class);
         return ok(Util.createResponse(jsonData,true));

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

@@ -3,6 +3,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 public class StudentStore {
     private static StudentStore instance;
@@ -22,19 +23,16 @@ public class StudentStore {
     }
 
     public Student getStudent(int id) {
-        if (students.containsKey(id))
-            return students.get(id);
-        return null;
+        return students.get(id);
     }
 
-    public List<Student> getAllStudents() {
-        return new ArrayList<Student>(students.values());
+    public Set<Student> getAllStudents() {
+        return (Set<Student>)students.values();
     }
 
     public Student updateStudent(Student student) {
 		int id=student.getId();
         if (students.containsKey(id)) {
-            student.setId(id);
             students.put(id, student);
             return student;
         }
@@ -42,11 +40,11 @@ public class StudentStore {
     }
 
     public boolean deleteStudent(int id) {
-
-        if (!students.containsKey(id))
+        Student student=students.remove(id);
+        if (student == null)
             return false;
-        students.remove(id);
-        return true;
+		else
+            return true;
 
     }
 }