docs: Adds explanation for MVC design pattern (#2302)

* Adds explanation for MVC design pattern

* minor updates

model-view-controller/README.md

@@ -12,6 +12,132 @@ the model, the view and the controller. Let the model manage the data, the view
 display the data and the controller mediate updating the data and redrawing the
 display.
 
+## Explanation
+
+Real-world example
+
+> Consider ICU room in hospital which displays the patients health information on device displays which 
+> are taking input from sensors connected to patient. Here, display's job is to display the data that 
+> it receives from the controller which in turn gets update from sensor model.
+
+In plain words
+
+> MVC separates the business logic from user interface by mediating Controller between Model & View.
+
+Wikipedia says
+
+> Model–view–controller (MVC) is commonly used for developing user interfaces that divide the 
+> related program logic into three interconnected elements. This is done to separate internal 
+> representations of information from the ways information is presented to and accepted from the user.
+
+**Programmatic Example**
+
+Consider following `GiantModel` model class that provides the health, fatigue & nourishment information.
+
+```java
+public class GiantModel {
+
+  private Health health;
+  private Fatigue fatigue;
+  private Nourishment nourishment;
+
+  /**
+   * Instantiates a new GiantModel.
+   */
+  public GiantModel(Health health, Fatigue fatigue, Nourishment nourishment) {
+    this.health = health;
+    this.fatigue = fatigue;
+    this.nourishment = nourishment;
+  }
+
+  public Health getHealth() {
+    return health;
+  }
+
+  public void setHealth(Health health) {
+    this.health = health;
+  }
+
+  public Fatigue getFatigue() {
+    return fatigue;
+  }
+
+  public void setFatigue(Fatigue fatigue) {
+    this.fatigue = fatigue;
+  }
+
+  public Nourishment getNourishment() {
+    return nourishment;
+  }
+
+  public void setNourishment(Nourishment nourishment) {
+    this.nourishment = nourishment;
+  }
+
+  @Override
+  public String toString() {
+    return String.format("The giant looks %s, %s and %s.", health, fatigue, nourishment);
+  }
+}
+```
+
+`GiantView` class to display received patient data.
+
+```java
+public class GiantView {
+
+  public void displayGiant(GiantModel giant) {
+    LOGGER.info(giant.toString());
+  }
+}
+```
+
+And `GiantController` class that takes updates from `GiantModel` & sends to `GiantView` for display.
+
+```java
+public class GiantController {
+
+  private final GiantModel giant;
+  private final GiantView view;
+
+  public GiantController(GiantModel giant, GiantView view) {
+    this.giant = giant;
+    this.view = view;
+  }
+
+  @SuppressWarnings("UnusedReturnValue")
+  public Health getHealth() {
+    return giant.getHealth();
+  }
+
+  public void setHealth(Health health) {
+    this.giant.setHealth(health);
+  }
+
+  @SuppressWarnings("UnusedReturnValue")
+  public Fatigue getFatigue() {
+    return giant.getFatigue();
+  }
+
+  public void setFatigue(Fatigue fatigue) {
+    this.giant.setFatigue(fatigue);
+  }
+
+  @SuppressWarnings("UnusedReturnValue")
+  public Nourishment getNourishment() {
+    return giant.getNourishment();
+  }
+
+  public void setNourishment(Nourishment nourishment) {
+    this.giant.setNourishment(nourishment);
+  }
+
+  public void updateView() {
+    this.view.displayGiant(giant);
+  }
+}
+```
+
 ## Class diagram
 ![alt text](./etc/model-view-controller.png "Model-View-Controller")