Law of Demeter in Java (eugenp#14465)

* Law of Demeter in Java

* Law of Demeter in Java

* Law of Demeter in Java

Author: Michaelin007

core-java-modules/core-java-lang-oop-others/src/main/java/com/baeldung/demeter/DemeterApplication.java

@@ -0,0 +1,16 @@
+package com.baeldung.demeter;
+
+public class DemeterApplication {
+    public static void main(String[] args) {
+   
+        Expenses expenses = new Expenses(100, 10);
+        Employee employee = new Employee();
+        employee.getDepartment()
+          .getManager()
+          .approveExpense(expenses);
+
+        Manager mgr = new Manager();
+        Employee emp = new Employee(mgr);
+        emp.submitExpense(expenses);
+    }
+}

core-java-modules/core-java-lang-oop-others/src/main/java/com/baeldung/demeter/Department.java

@@ -0,0 +1,11 @@
+package com.baeldung.demeter;
+
+public class Department {
+
+    private Manager manager = new Manager();
+
+    public Manager getManager() {
+        return manager;
+    }
+
+}

core-java-modules/core-java-lang-oop-others/src/main/java/com/baeldung/demeter/Employee.java

@@ -0,0 +1,23 @@
+package com.baeldung.demeter;
+
+public class Employee {
+    private Department department = new Department();
+    private Manager manager;
+
+    public Employee() {
+
+    }
+
+    Employee(Manager manager) {
+        this.manager = manager;
+    }
+
+    public Department getDepartment() {
+        return department;
+    }
+
+    public void submitExpense(Expenses expenses) {
+        manager.approveExpense(expenses);
+    }
+
+}

core-java-modules/core-java-lang-oop-others/src/main/java/com/baeldung/demeter/Expenses.java

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+package com.baeldung.demeter;
+
+public class Expenses {
+
+    private double total;
+    private double tax;
+
+    public Expenses(double total, double tax) {
+        this.total = total;
+        this.tax = tax;
+    }
+
+    public double total() {
+        return total + tax;
+    }
+}

core-java-modules/core-java-lang-oop-others/src/main/java/com/baeldung/demeter/Greetings.java

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+package com.baeldung.demeter;
+
+public class Greetings {
+
+    HelloCountries helloCountries = new HelloCountries();
+
+    private static HelloCountries helloCountriesStatic = new HelloCountries();
+
+    public String generalGreeting() {
+        return "Welcome" + world();
+    }
+
+    public String world() {
+        return "Hello World";
+    }
+
+    public String getHelloBrazil() {
+        HelloCountries helloCountries = new HelloCountries();
+        return helloCountries.helloBrazil();
+    }
+
+    public String getHelloIndia(HelloCountries helloCountries) {
+        return helloCountries.helloIndia();
+    }
+
+    public String getHelloJapan() {
+        return helloCountries.helloJapan();
+    }
+
+    public String getHellStaticWorld() {
+        return helloCountriesStatic.helloStaticWorld();
+    }
+}

core-java-modules/core-java-lang-oop-others/src/main/java/com/baeldung/demeter/HelloCountries.java

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+package com.baeldung.demeter;
+
+public class HelloCountries {
+
+    public String helloBrazil() {
+        return "Hello Brazil";
+    }
+
+    public String helloIndia() {
+        return "Hello India";
+    }
+
+    public String helloJapan() {
+        return "Hello Japan";
+    }
+
+    public String helloStaticWorld() {
+        return "Hello Static World";
+    }
+}

core-java-modules/core-java-lang-oop-others/src/main/java/com/baeldung/demeter/Manager.java

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+package com.baeldung.demeter;
+
+public class Manager {
+
+    public void approveExpense(Expenses expenses) {
+        System.out.println("Expense approved" + expenses.total());
+    }
+
+}