Updated SRP, LSP and OCP files

src/oops/SOLID/lsp/stack/before/StackWrong.java

@@ -14,19 +14,30 @@
  * so objects of ArrayList are not fully replaceable by the objects of stack.   
  * 
  */
-public class StackWrong extends ArrayList<Integer>{
+public class StackWrong{
 	private int topPointer = 0;
+	private ArrayList<Integer> list = new ArrayList<>(); 
 
 	public void push(Integer a) {
-		add(topPointer, a);
+		list.add(topPointer, a);
 		topPointer++;
 	}	
 	public void pop() {
-		remove(topPointer-1);
+		if(topPointer == 0)
+			return;
+		list.remove(topPointer-1);
 		topPointer--;
 	}
+
+	public void clear() {
+		list.clear();
+		topPointer = 0;
+	}
+
 	public Integer top() {
-		return get(topPointer-1);
+		if(topPointer == 0)
+			return -1;
+		return list.get(topPointer-1);
 	}
 
 	public static void main(String[] args) {

src/oops/SOLID/openClosePrinciple/before/client/CalculateTaxesClient.java

@@ -26,10 +26,10 @@ public static void main(String[] args) {
         for (Employee employee: employees){
 
             // compute individual tax
-            double tax = TaxCalculator.calculate(employee);
+            double tax = employee.taxCalculate();
             String formattedTax = currencyFormatter.format(tax);
             // add to company total taxes
-            totalTaxes += TaxCalculator.calculate(employee);
+            totalTaxes += tax;
         }
     }
 }

src/oops/SOLID/openClosePrinciple/before/employees/Employee.java

@@ -57,5 +57,7 @@ public void setNbHoursPerWeek(int nbHoursPerWeek) {
     public String getFullName(){
         return this.firstName + " " + this.lastName;
     }
+
+	public abstract double taxCalculate();
 }
 

src/oops/SOLID/openClosePrinciple/before/employees/FullTimeEmployee.java

@@ -1,8 +1,18 @@
 package oops.SOLID.openClosePrinciple.before.employees;
 
+import oops.SOLID.openClosePrinciple.before.taxes.FullTimeEmpTaxCalculate;
+import oops.SOLID.openClosePrinciple.before.taxes.TaxCalculator;
+
 public class FullTimeEmployee extends Employee {
     public FullTimeEmployee(String fullName, int monthlyIncome) {
         super(fullName, monthlyIncome);
         this.setNbHoursPerWeek(40);
     }
+
+	@Override
+	public double taxCalculate() {
+		// TODO Auto-generated method stub
+		TaxCalculator calculator = new FullTimeEmpTaxCalculate();
+		return calculator.calculate(this); // Employee emp = new FullTimeEmployee()
+	}
 }

src/oops/SOLID/openClosePrinciple/before/employees/Intern.java

@@ -1,8 +1,18 @@
 package oops.SOLID.openClosePrinciple.before.employees;
 
+import oops.SOLID.openClosePrinciple.before.taxes.InternTaxCalculator;
+import oops.SOLID.openClosePrinciple.before.taxes.TaxCalculator;
+
 public class Intern extends Employee {
     public Intern(String fullName, int monthlyIncome, int nbHours) {
         super(fullName, monthlyIncome);
         setNbHoursPerWeek(nbHours);
     }
+
+	@Override
+	public double taxCalculate() {
+		// TODO Auto-generated method stub
+		TaxCalculator calculator = new InternTaxCalculator();
+		return calculator.calculate(this);
+	}
 }

src/oops/SOLID/openClosePrinciple/before/employees/PartTimeEmployee.java

@@ -1,8 +1,18 @@
 package oops.SOLID.openClosePrinciple.before.employees;
 
+import oops.SOLID.openClosePrinciple.before.taxes.PartTimeEmployeeTaxCalculator;
+import oops.SOLID.openClosePrinciple.before.taxes.TaxCalculator;
+
 public class PartTimeEmployee extends Employee {
     public PartTimeEmployee(String fullName, int monthlyIncome) {
         super(fullName, monthlyIncome);
         this.setNbHoursPerWeek(20);
     }
+
+	@Override
+	public double taxCalculate() {
+		// TODO Auto-generated method stub
+		TaxCalculator calculator = new PartTimeEmployeeTaxCalculator();
+		return calculator.calculate(this);
+	}
 }

src/oops/SOLID/openClosePrinciple/before/taxes/FullTimeEmpTaxCalculate.java

@@ -0,0 +1,20 @@
+package oops.SOLID.openClosePrinciple.before.taxes;
+
+import oops.SOLID.openClosePrinciple.before.employees.Employee;
+
+public class FullTimeEmpTaxCalculate implements TaxCalculator{
+
+	private final static int INCOME_TAX_PERCENTAGE = 30;
+	private final static int PROFESSIONAL_TAX_PERCENTAGE = 2;
+	private final static int EDUCATION_CESS = 1;
+
+	@Override
+	public double calculate(Employee emp) {
+		// TODO Auto-generated method stub
+		return 
+              (emp.getMonthlyIncome() * PROFESSIONAL_TAX_PERCENTAGE * 12) / 100 +
+              (emp.getMonthlyIncome() * INCOME_TAX_PERCENTAGE * 12) / 100 +
+              (emp.getMonthlyIncome() * EDUCATION_CESS * 12) / 100;
+	}
+
+}

src/oops/SOLID/openClosePrinciple/before/taxes/InternTaxCalculator.java

@@ -0,0 +1,16 @@
+package oops.SOLID.openClosePrinciple.before.taxes;
+
+import oops.SOLID.openClosePrinciple.before.employees.Employee;
+
+public class InternTaxCalculator implements TaxCalculator{
+
+	@Override
+	public double calculate(Employee emp) {
+		int income = emp.getMonthlyIncome();
+		if(income * 12 < 300000)
+			return 0;
+		else
+			return (income * 12 * 15)/100;
+	}
+
+}

src/oops/SOLID/openClosePrinciple/before/taxes/PartTimeEmployeeTaxCalculator.java

@@ -0,0 +1,20 @@
+package oops.SOLID.openClosePrinciple.before.taxes;
+
+import oops.SOLID.openClosePrinciple.before.employees.Employee;
+
+public class PartTimeEmployeeTaxCalculator implements TaxCalculator{
+
+	private final static int INCOME_TAX_PERCENTAGE = 20;
+	private final static int PROFESSIONAL_TAX_PERCENTAGE = 3;
+	private final static int EDUCATION_CESS = 1;
+
+	@Override
+	public double calculate(Employee emp) {
+		// TODO Auto-generated method stub
+		return 
+              (emp.getMonthlyIncome() * PROFESSIONAL_TAX_PERCENTAGE * 12) / 100 +
+              (emp.getMonthlyIncome() * INCOME_TAX_PERCENTAGE * 12) / 100 +
+              (emp.getMonthlyIncome() * EDUCATION_CESS * 12) / 100;
+	}
+
+}

src/oops/SOLID/openClosePrinciple/before/taxes/TaxCalculator.java

@@ -2,15 +2,8 @@
 
 import oops.SOLID.openClosePrinciple.before.employees.Employee;
 
-public class TaxCalculator {
-    private final static int INCOME_TAX_PERCENTAGE = 20;
-    private final static int PROFESSIONAL_TAX_PERCENTAGE = 3;
+public interface TaxCalculator {
 
-
-    public static double calculate(Employee employee) {
-        return 
-                (employee.getMonthlyIncome() * PROFESSIONAL_TAX_PERCENTAGE) / 100 +
-                (employee.getMonthlyIncome() * INCOME_TAX_PERCENTAGE) / 100;
-
-    }
+	double calculate(Employee emp);
+
 }

src/oops/SOLID/singleResponsibilityPrinciple/before/Employee.java

@@ -1,10 +1,5 @@
 package oops.SOLID.singleResponsibilityPrinciple.before;
 
-import java.io.IOException;
-import java.nio.file.Files;
-import java.nio.file.Path;
-import java.nio.file.Paths;
-
 /*
 Models an employee form a business perspective
  */
@@ -53,7 +48,7 @@ public int getNbHoursPerWeek() {
 
     public void setNbHoursPerWeek(int nbHoursPerWeek) {
         if(nbHoursPerWeek <= 0){
-            throw new IllegalArgumentException("Income must be positive");
+            throw new IllegalArgumentException("Number of working hours per week must be positive");
         }
 
         this.nbHoursPerWeek = nbHoursPerWeek;
@@ -63,9 +58,9 @@ public String getFullName(){
         return this.firstName + " " + this.lastName;
     }
 
-    public  void save(){
-        try {
-        	Employee employee =this;
+    public String serializeData(){
+
+        	Employee employee = this;
             StringBuilder sb = new StringBuilder();
             sb.append("### EMPLOYEE RECORD ####");
             sb.append(System.lineSeparator());
@@ -82,13 +77,7 @@ public  void save(){
             sb.append(employee.monthlyIncome);
             sb.append(System.lineSeparator());
 
-            Path path = Paths.get(employee.getFullName()
-                    .replace(" ","_") + ".rec");
-            Files.write(path, sb.toString().getBytes());
-
-            System.out.println("Saved employee " + employee.toString());
-        } catch (IOException e){
-            System.out.println("ERROR: Could not save employee. " + e);
-        }
+
+		return sb.toString();
     }
 }

src/oops/SOLID/singleResponsibilityPrinciple/before/EmployeeRepository.java

@@ -1,5 +1,9 @@
 package oops.SOLID.singleResponsibilityPrinciple.before;
 
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
 import java.util.Arrays;
 import java.util.List;
 
@@ -15,5 +19,19 @@ public List<Employee> findAll(){
         Employee magda = new PartTimeEmployee("Magda Iovan", 920);
 
         return Arrays.asList(anna, billy, steve, magda);
+
+    }
+
+    public void save(Employee emp) {
+    	try {
+    		String serializedData = emp.serializeData();
+    		Path path = Paths.get(emp.getFullName()
+                    .replace(" ","_") + ".rec");
+            Files.write(path, serializedData.getBytes());
+
+    	}catch (IOException e){
+            System.out.println("ERROR: Could not save employee. " + e);
+        }
+
     }
 }

src/oops/SOLID/singleResponsibilityPrinciple/before/SaveEmployeesMain.java

@@ -10,7 +10,7 @@ public static void main(String[] args) {
 
         // Save all
         for (Employee e : employees){
-            e.save();
+            repository.save(e);
         }
     }
 }