OOP: Encapsulation

slgobinath · slgobinath · commit 6362cedeb4c6 · 2015-01-30T16:02:16.000+05:30
diff --git a/objectorientedprogramming/encapsulation/DoctorDemo.java b/objectorientedprogramming/encapsulation/DoctorDemo.java
@@ -0,0 +1,76 @@
+/**
+ * Sample code used to explain Object Oriented Programming.
+ * Version History:
+ * 1.0  -   The orginal source code.
+ * 1.1  -   All the properties of Animals have been encapsulated.
+ *
+ * @version 1.1
+ * @author L.Gobinath
+ */
+public class DoctorDemo {
+    public static void main(String[] args) {
+        Cat cat = new Cat();
+        Dog dog = new Dog();
+        VeterinaryDoctor doctor = new VeterinaryDoctor();
+        cat.setAge(4);
+        dog.setAge(2);
+        doctor.treatCat(cat);
+        doctor.treatDog(dog);
+    }
+}
+
+class VeterinaryDoctor {
+    /**
+     * Give treatment to a cat.
+     * @param cat The cat.
+     */
+    public void treatCat(Cat cat) {
+        if (cat.getAge() < 3) { // Changed to getAge()
+            System.out.println("Treatment C1");
+        } else {
+            System.out.println("Treatment C2");
+        }
+    }
+
+    /**
+     * Give treatment to a dog.
+     * @param dog The dog.
+     */
+    public void treatDog(Dog dog) {
+        if (dog.getAge() < 5) { // Changed to getAge()
+            System.out.println("Treatment D1");
+        } else {
+            System.out.println("Treatment D2");
+        }
+    }
+}
+
+/**
+ * Encapsulated Cat.
+ */
+class Cat {
+    private int age;
+
+    public int getAge() {
+        return this.age;
+    }
+
+    public void setAge(int age) {
+        this.age = age;
+    }
+}
+
+/**
+ * Encapsulated Dog.
+ */
+class Dog {
+    private int age;
+
+    public int getAge() {
+        return this.age;
+    }
+
+    public void setAge(int age) {
+        this.age = age;
+    }
+}
diff --git a/objectorientedprogramming/encapsulation/v1.0/Book.java b/objectorientedprogramming/encapsulation/v1.0/Book.java
@@ -0,0 +1,22 @@
+/**
+ * Book class used to explain the encapsulation.
+ *
+ * @version 1.0
+ * @author L.Gobinath
+ */
+public class Book {
+    // Title of the book.
+    String title;
+    // Author of the book.
+    String author;
+    // Price of the book.
+    double price;
+
+    /**
+     * Print the total amount for given quantity.
+     * @param qty The quantity
+     */
+    public void sell(int qty) {
+        System.out.println("Total: $" + (qty * price));
+    }
+}
diff --git a/objectorientedprogramming/encapsulation/v1.0/BookShop.java b/objectorientedprogramming/encapsulation/v1.0/BookShop.java
@@ -0,0 +1,18 @@
+/**
+ * Testing class for Book class.
+ *
+ * @version 1.0
+ * @author L.Gobinath
+ */
+public class BookShop {
+    public static void main(String[] args) {
+        Book book = new Book();
+        book.title = "Hamlet";
+        book.author = "William Shakespeare";
+        book.price = -5.95; // A negative price!
+
+        System.out.println("Title: " + book.title);
+        System.out.println("Price: $" + book.price);
+        book.sell(2);
+    }
+}
diff --git a/objectorientedprogramming/encapsulation/v1.1/Book.java b/objectorientedprogramming/encapsulation/v1.1/Book.java
@@ -0,0 +1,34 @@
+/**
+ * Book class used to explain the encapsulation.
+ *
+ * @version 1.1
+ * @author L.Gobinath
+ */
+public class Book {
+    // Title of the book.
+    String title;
+    // Author of the book.
+    String author;
+    // Price of the book.
+    double price;
+
+    /**
+     * Set the price.
+     * @param price Price of the book.
+     */
+    public void setPrice(double price) {
+        if (price > 0) {
+            this.price = price;
+        } else {
+            System.out.println("Invalid price");
+        }
+    }
+
+    /**
+     * Print the total amount for given quantity.
+     * @param qty The quantity
+     */
+    public void sell(int qty) {
+        System.out.println("Total: $" + (qty * price));
+    }
+}
diff --git a/objectorientedprogramming/encapsulation/v1.1/BookShop.java b/objectorientedprogramming/encapsulation/v1.1/BookShop.java
@@ -0,0 +1,20 @@
+/**
+ * Testing class for Book class.
+ *
+ * @version 1.1
+ * @author L.Gobinath
+ */
+public class BookShop {
+	public static void main(String[] args) {
+		Book book = new Book();
+		book.title = "Hamlet";
+		book.author = "William Shakespeare";
+		// Still directly assigning the value.
+		// I am a rule breaker.
+		book.price = -5.95;
+
+		System.out.println("Title: " + book.title);
+		System.out.println("Price: $" + book.price);
+		book.sell(2);
+	}
+}
diff --git a/objectorientedprogramming/encapsulation/v1.2/Book.java b/objectorientedprogramming/encapsulation/v1.2/Book.java
@@ -0,0 +1,42 @@
+/**
+ * Book class used to explain the encapsulation.
+ * 
+ * @version 1.2
+ * @author L.Gobinath
+ */
+public class Book {
+    // Title of the book.
+    String title;
+    // Author of the book.
+    String author;
+    // Price of the book.
+    private double price;
+
+    /**
+     * Set the price.
+     * @param price Price of the book.
+     */
+    public void setPrice(double price) {
+        if (price > 0) {
+            this.price = price;
+        } else {
+        	System.out.println("Invalid price");
+        }
+    }
+
+    /**
+     * Get the price.
+     * @return Price of the book.
+     */
+    public double getPrice() {
+        return this.price;
+    }
+
+    /**
+     * Print the total amount for given quantity.
+     * @param qty The quantity
+     */
+    public void sell(int qty) {
+        System.out.println("Total: $" + (qty * price));
+    }
+}
diff --git a/objectorientedprogramming/encapsulation/v1.2/BookShop.java b/objectorientedprogramming/encapsulation/v1.2/BookShop.java
@@ -0,0 +1,20 @@
+/**
+ * Testing class for Book class.
+ *
+ * @version 1.2
+ * @author L.Gobinath
+ */
+public class BookShop {
+	public static void main(String[] args) {
+		Book book = new Book();
+		book.title = "Hamlet";
+		book.author = "William Shakespeare";
+		book.setPrice(-5.95);	// Error message
+		book.setPrice(5.95);
+
+		System.out.println("Title: " + book.title);
+		// System.out.println("Price: $" + book.price);
+		System.out.println("Price: $" + book.getPrice());
+		book.sell(2);
+	}
+}
diff --git a/objectorientedprogramming/encapsulation/v2.0/Book.java b/objectorientedprogramming/encapsulation/v2.0/Book.java
@@ -0,0 +1,74 @@
+/**
+ * Book class used to explain the encapsulation.
+ *
+ * @version 2.0
+ * @author L.Gobinath
+ */
+public class Book {
+    // Title of the book.
+    private String title;
+    // Author of the book.
+    private String author;
+    // Price of the book.
+    private double price;
+
+    /**
+     * Get the title.
+     * @return The title of the book.
+     */
+    public String getTitle() {
+        return this.title;
+    }
+
+    /**
+     * Set the title.
+     * @param title The title of the book.
+     */
+    public void setTitle(String title) {
+        this.title = title;
+    }
+
+    /**
+     * Get the author of the book.
+     * @return The author of the book.
+     */
+    public String getAuthor() {
+        return this.author;
+    }
+
+    /**
+     * Set the author of the book.
+     * @param author The author of the book.
+     */
+    public void setAuthor(String author) {
+        this.author = author;
+    }
+
+    /**
+     * Set the price.
+     * @param price Price of the book.
+     */
+    public void setPrice(double price) {
+        if (price > 0) {
+            this.price = price;
+        } else {
+            System.out.println("Invalid price");
+        }
+    }
+
+    /**
+     * Get the price.
+     * @return Price of the book.
+     */
+    public double getPrice() {
+        return this.price;
+    }
+
+    /**
+     * Print the total amount for given quantity.
+     * @param qty The quantity
+     */
+    public void sell(int qty) {
+        System.out.println("Total: $" + (qty * price));
+    }
+}
diff --git a/objectorientedprogramming/encapsulation/v2.0/BookShop.java b/objectorientedprogramming/encapsulation/v2.0/BookShop.java
@@ -0,0 +1,18 @@
+/**
+ * Testing class for Book class.
+ *
+ * @version 2.0
+ * @author L.Gobinath
+ */
+public class BookShop {
+    public static void main(String[] args) {
+        Book book = new Book();
+        book.setTitle("Hamlet");
+        book.setAuthor("William Shakespeare");
+        book.setPrice(5.95);
+
+        System.out.println("Title: " + book.getTitle());
+        System.out.println("Price: $" + book.getPrice());
+        book.sell(2);
+    }
+}
