From eb62012ec24c1733074e12d0a74402d83f658036 Mon Sep 17 00:00:00 2001
From: Tanmay <tanmaykacker40@gmail.com>
Date: Wed, 7 Sep 2022 13:19:44 +0100
Subject: [PATCH] Adds code for polymorphism.
---
.../oop/src/main/java/com/scaler/lld/App.java | 61 ++++++++++++++-----
.../java/com/scaler/lld/scaler/Mentor.java | 25 ++++++++
.../java/com/scaler/lld/scaler/Student.java | 11 +++-
.../main/java/com/scaler/lld/scaler/User.java | 24 +++++++-
4 files changed, 102 insertions(+), 19 deletions(-)
create mode 100644 oop/code/oop/src/main/java/com/scaler/lld/scaler/Mentor.java
diff --git a/oop/code/oop/src/main/java/com/scaler/lld/App.java b/oop/code/oop/src/main/java/com/scaler/lld/App.java
index 58c2e48..5008657 100644
--- a/oop/code/oop/src/main/java/com/scaler/lld/App.java
+++ b/oop/code/oop/src/main/java/com/scaler/lld/App.java
@@ -1,27 +1,58 @@
package com.scaler.lld;
-import com.scaler.lld.basics.OopBankAccount;
+import java.util.List;
+
+import com.scaler.lld.scaler.Student;
+import com.scaler.lld.scaler.User;
/**
* Hello world!
*
*/
-public class App
-{
- public static void main( String[] args )
- {
- // Create accounts for Alice and Bob
- OopBankAccount accountAlice = new OopBankAccount(1, 1000, "Alice");
- OopBankAccount accountBob = new OopBankAccount(2, 2000, "Bob");
+public class App {
+ public static void main(String[] args) {
+ User student = new Student("student", "student@scaler.in", "batch", 100);
+ student.printInfo(); // inheritance
+ }
- System.out.println("\nAlice's balance: " + accountAlice.getBalance());
- System.out.println("Bob's balance: " + accountBob.getBalance());
+ public static void resetEmail(List<User> users) {
+ for (User user : users) {
+ user.changeEmail("");
- System.out.println("\nTransferring $100 from Alice to Bob");
- // Transfer $100 from Alice to Bob
- accountAlice.transfer(accountBob, 100);
+ if (user instanceof Student) {
+ Student student = (Student) user;
+
+ System.out.println("Name :" + student.getName() + " " + student.getPsp());
+
+ student.setPsp(0);
+ System.out.println("Name :" + student.getName() + " " + student.getPsp());
+
+ }
+
+ }
- System.out.println("\nAlice's balance: " + accountAlice.getBalance());
- System.out.println("Bob's balance: " + accountBob.getBalance());
}
}
+
+// Reusable code
+// In order to reset email, I just had to call the parent's changeEmail fn
+// Instead of defining a method for each class
+// instanceof
+// A a = (A) b;
+// 6:05
+// 10:35
+// Three types of DP
+// 1. Creational - OOP
+// Factory - Simple Factory - No OOP
+// 2. Structural -
+// 3. Behavioural -
+
+// 1. Subtyping
+// - Compile and run time
+
+// Method overloading - Compile time
+// 2. Generic Polymorphism
+// 3. Adhoc polymorphism - Duck Typing
+
+// PATCH /edit-student (JSON patchBody)
+// { field: "name", op: "set", value: "Tanmay"}
\ No newline at end of file
diff --git a/oop/code/oop/src/main/java/com/scaler/lld/scaler/Mentor.java b/oop/code/oop/src/main/java/com/scaler/lld/scaler/Mentor.java
new file mode 100644
index 0000000..94e351f
--- /dev/null
+++ b/oop/code/oop/src/main/java/com/scaler/lld/scaler/Mentor.java
@@ -0,0 +1,25 @@
+package com.scaler.lld.subtyping;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import com.scaler.lld.scaler.Student;
+import com.scaler.lld.scaler.User;
+
+import lombok.Getter;
+import lombok.Setter;
+
+// Step 1 - Extend parent class
+@Getter
+@Setter
+public class Mentor extends User {
+ private List<Student> mentees = new ArrayList<>();
+ private String company;
+
+ public Mentor(String name, String email, List<Student> mentees, String company) {
+ super(name, email);
+ this.mentees = mentees;
+ this.company = company;
+ }
+
+}
diff --git a/oop/code/oop/src/main/java/com/scaler/lld/scaler/Student.java b/oop/code/oop/src/main/java/com/scaler/lld/scaler/Student.java
index b41f93f..b70a0b0 100644
--- a/oop/code/oop/src/main/java/com/scaler/lld/scaler/Student.java
+++ b/oop/code/oop/src/main/java/com/scaler/lld/scaler/Student.java
@@ -1,12 +1,10 @@
package com.scaler.lld.scaler;
import lombok.Getter;
-import lombok.NoArgsConstructor;
import lombok.Setter;
@Getter
@Setter
-@NoArgsConstructor
public class Student extends User {
private String batchName;
@@ -25,9 +23,16 @@ public class Student extends User {
this.psp = psp;
}
- public void changeBatch(String batchName) {
+ public Student() {
+ }
+
+ void changeBatch(String batchName) {
this.batchName = batchName;
}
+ @Override
+ public void printInfo() {
+ System.out.println("\nStudent: " + getName() + " " + getBatchName());
+ }
}
\ No newline at end of file
diff --git a/oop/code/oop/src/main/java/com/scaler/lld/scaler/User.java b/oop/code/oop/src/main/java/com/scaler/lld/scaler/User.java
index ce6e403..c81c45b 100644
--- a/oop/code/oop/src/main/java/com/scaler/lld/scaler/User.java
+++ b/oop/code/oop/src/main/java/com/scaler/lld/scaler/User.java
@@ -7,8 +7,8 @@ import lombok.Setter;
@Getter
@Setter
-@NoArgsConstructor
@AllArgsConstructor
+@NoArgsConstructor
public class User {
private String name;
private String email;
@@ -16,4 +16,26 @@ public class User {
public void changeEmail(String email) {
this.email = email;
}
+
+ // Method overloading
+ // Method signature:
+ // 1. Method name
+ // 2. # of args
+ // 3. Data type of args
+
+ public void printInfo() {
+ }
+
+ public void printInfo(String title) {
+ System.out.println(" \n User: " + title + " " + this.getName());
+ }
}
+
+// Interfaces
+// Class - Blueprint
+// Interface - Blue print of behaviour
+// Database db = new MySqlDB();
+// Interfaces - define methods with an impl.
+// Abstract - mixture of interface and class
+// implemented methods + not-implemented
+// Abstract classes - state