Update README.md

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

@@ -0,0 +1,37 @@
+package store;
+
+import model.Student;
+
+import java.util.*;
+
+public class StudentStore {
+    private Map<Integer, Student> students = new HashMap<>();
+
+    public Optional<Student> addStudent(Student student) {
+        int id = students.size();
+        student.setId(id);
+        students.put(id, student);
+        return Optional.ofNullable(student);
+    }
+
+    public Optional<Student> getStudent(int id) {
+        return Optional.ofNullable(students.get(id));
+    }
+
+    public Set<Student> getAllStudents() {
+        return new HashSet<>(students.values());
+    }
+
+    public Optional<Student> updateStudent(Student student) {
+        int id = student.getId();
+        if (students.containsKey(id)) {
+            students.put(id, student);
+            return Optional.ofNullable(student);
+        }
+        return Optional.empty();
+    }
+
+    public boolean deleteStudent(int id) {
+        return students.remove(id) != null;
+    }
+}