Attempt1- LLD2

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

@@ -1,6 +1,8 @@
 package oops.SOLID.lsp.stack.before;
 
-import java.util.ArrayList;
+import java.util.Stack;
+import java.util.Vector;
+
 /*
  * Stack is-a list with push() pop() methods.
  * So can we create a stack by extending an ArrayList class?
@@ -14,16 +16,18 @@
  * so objects of ArrayList are not fully replaceable by the objects of stack.   
  * 
  */
-public class StackWrong extends ArrayList<Integer>{
+public class StackWrong extends Vector<Integer> {
 	private int topPointer = 0;
 
-	public void push(Integer a) {
+	public Integer push(Integer a) {
 		add(topPointer, a);
 		topPointer++;
-	}	
-	public void pop() {
+		return a;
+	}
+	public Integer pop() {
 		remove(topPointer-1);
 		topPointer--;
+		return null;
 	}
 	public Integer top() {
 		return get(topPointer-1);

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

@@ -7,6 +7,7 @@
 import oops.SOLID.openClosePrinciple.before.employees.Employee;
 import oops.SOLID.openClosePrinciple.before.persistence.EmployeeRepository;
 import oops.SOLID.openClosePrinciple.before.taxes.TaxCalculator;
+import oops.SOLID.openClosePrinciple.before.taxes.TaxCalculatorProvider;
 
 
 public class CalculateTaxesClient {
@@ -24,12 +25,15 @@ public static void main(String[] args) {
 
         double totalTaxes = 0;
         for (Employee employee: employees){
+            TaxCalculator taxCalculator = TaxCalculatorProvider.getTaxCalculator(employee);
 
             // compute individual tax
-            double tax = TaxCalculator.calculate(employee);
+            double tax = taxCalculator.calculate(employee);
             String formattedTax = currencyFormatter.format(tax);
             // add to company total taxes
-            totalTaxes += TaxCalculator.calculate(employee);
+            totalTaxes += taxCalculator.calculate(employee);
+
+            System.out.println(employee+", TAX = " +formattedTax);
         }
     }
 }

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

@@ -57,5 +57,13 @@ public void setNbHoursPerWeek(int nbHoursPerWeek) {
     public String getFullName(){
         return this.firstName + " " + this.lastName;
     }
+
+    public boolean incomeLessThan(int incomeCap){
+        return this.monthlyIncome < incomeCap;
+    }
+
+    public double getMonthlyIncomePercentage(int incomeTaxPercentage){
+        return (this.monthlyIncome*incomeTaxPercentage)/100;
+    }
 }
 

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

@@ -0,0 +1,28 @@
+package oops.SOLID.openClosePrinciple.before.taxes;
+
+import oops.SOLID.openClosePrinciple.before.employees.Employee;
+
+public class FullTimeEmployeeTaxCalculator implements TaxCalculator{
+    private final static int INCOME_TAX_PERCENTAGE = 30;
+    private final static int PROFESSIONAL_TAX_PERCENTAGE = 2;
+    private final static int EDUCATION_TAX_PERCENTAGE = 1;
+
+    public double calculate(Employee employee) {
+        return calculateIncomeTax(employee) + calculateProfessionalTax(employee) +calculateEducationTax(employee);
+    }
+
+    @Override
+    public double calculateIncomeTax(Employee employee) {
+        return employee.getMonthlyIncomePercentage(INCOME_TAX_PERCENTAGE);
+    }
+
+    @Override
+    public double calculateProfessionalTax(Employee employee) {
+        return employee.getMonthlyIncomePercentage(PROFESSIONAL_TAX_PERCENTAGE);
+    }
+
+    @Override
+    public double calculateEducationTax(Employee employee) {
+        return employee.getMonthlyIncomePercentage(EDUCATION_TAX_PERCENTAGE);
+    }
+}

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

@@ -0,0 +1,30 @@
+package oops.SOLID.openClosePrinciple.before.taxes;
+
+import oops.SOLID.openClosePrinciple.before.employees.Employee;
+
+public class InternTaxCalculator implements TaxCalculator {
+    private final static int INCOME_TAX_PERCENTAGE = 15;
+    private final static int INCOME_CAP=300000;
+    private final static int PROFESSIONAL_TAX_PERCENTAGE = 0;
+    private final static int EDUCATION_TAX_PERCENTAGE = 0;
+
+
+    public double calculate(Employee employee) {
+        return calculateIncomeTax(employee) + calculateProfessionalTax(employee) +calculateEducationTax(employee);
+    }
+
+    @Override
+    public double calculateIncomeTax(Employee employee) {
+        return employee.incomeLessThan(INCOME_CAP)?0:employee.getMonthlyIncomePercentage(INCOME_TAX_PERCENTAGE);
+    }
+
+    @Override
+    public double calculateProfessionalTax(Employee employee) {
+        return employee.getMonthlyIncomePercentage(PROFESSIONAL_TAX_PERCENTAGE);
+    }
+
+    @Override
+    public double calculateEducationTax(Employee employee) {
+        return employee.getMonthlyIncomePercentage(EDUCATION_TAX_PERCENTAGE);
+    }
+}

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

@@ -0,0 +1,28 @@
+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_TAX_PERCENTAGE = 1;
+
+    public double calculate(Employee employee) {
+        return calculateIncomeTax(employee) + calculateProfessionalTax(employee) +calculateEducationTax(employee);
+    }
+
+    @Override
+    public double calculateIncomeTax(Employee employee) {
+        return employee.getMonthlyIncomePercentage(INCOME_TAX_PERCENTAGE);
+    }
+
+    @Override
+    public double calculateProfessionalTax(Employee employee) {
+        return employee.getMonthlyIncomePercentage(PROFESSIONAL_TAX_PERCENTAGE);
+    }
+
+    @Override
+    public double calculateEducationTax(Employee employee) {
+        return employee.getMonthlyIncomePercentage(EDUCATION_TAX_PERCENTAGE);
+    }
+}

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

@@ -2,15 +2,10 @@
 
 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 employee);
+    double calculateIncomeTax(Employee employee);
+    double calculateProfessionalTax(Employee employee);
+    double calculateEducationTax(Employee employee);
 }

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

@@ -0,0 +1,15 @@
+package oops.SOLID.openClosePrinciple.before.taxes;
+
+import oops.SOLID.openClosePrinciple.before.employees.*;
+
+public class TaxCalculatorProvider {
+    private static final TaxCalculator FullTimeEmployeeTaxCalculator = new FullTimeEmployeeTaxCalculator();
+    private static final TaxCalculator PartTimeEmployeeTaxCalculator = new PartTimeEmployeeTaxCalculator();
+    private static final TaxCalculator InternTaxCalculator = new InternTaxCalculator();
+    public static final TaxCalculator getTaxCalculator(Employee employee){
+        if(employee instanceof FullTimeEmployee) return FullTimeEmployeeTaxCalculator;
+        if(employee instanceof PartTimeEmployee) return PartTimeEmployeeTaxCalculator;
+        if(employee instanceof Intern) return InternTaxCalculator;
+        return null;
+    }
+}

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
  */
@@ -63,32 +58,27 @@ public String getFullName(){
         return this.firstName + " " + this.lastName;
     }
 
-    public  void save(){
-        try {
-        	Employee employee =this;
-            StringBuilder sb = new StringBuilder();
-            sb.append("### EMPLOYEE RECORD ####");
-            sb.append(System.lineSeparator());
-            sb.append("NAME: ");
-            sb.append(employee.firstName + " " + employee.lastName);
-            sb.append(System.lineSeparator());
-            sb.append("POSITION: ");
-            sb.append(employee.getClass().getTypeName());
-            sb.append(System.lineSeparator());
-            sb.append("EMAIL: ");
-            sb.append(employee.getEmail());
-            sb.append(System.lineSeparator());
-            sb.append("MONTHLY WAGE: ");
-            sb.append(employee.monthlyIncome);
-            sb.append(System.lineSeparator());
-
-            Path path = Paths.get(employee.getFullName()
-                    .replace(" ","_") + ".rec");
-            Files.write(path, sb.toString().getBytes());
+    public String serialize() {
+        Employee employee = this;
+        StringBuilder sb = new StringBuilder();
+        sb.append("### EMPLOYEE RECORD ####");
+        sb.append(System.lineSeparator());
+        sb.append("NAME: ");
+        sb.append(employee.firstName + " " + employee.lastName);
+        sb.append(System.lineSeparator());
+        sb.append("POSITION: ");
+        sb.append(employee.getClass().getTypeName());
+        sb.append(System.lineSeparator());
+        sb.append("EMAIL: ");
+        sb.append(employee.getEmail());
+        sb.append(System.lineSeparator());
+        sb.append("MONTHLY WAGE: ");
+        sb.append(employee.monthlyIncome);
+        sb.append(System.lineSeparator());
+        return sb.toString();
+    }
 
-            System.out.println("Saved employee " + employee.toString());
-        } catch (IOException e){
-            System.out.println("ERROR: Could not save employee. " + e);
-        }
+    public String generateKey(){
+        return this.firstName+"_"+this.lastName;
     }
 }

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;
 
@@ -16,4 +20,20 @@ public List<Employee> findAll(){
 
         return Arrays.asList(anna, billy, steve, magda);
     }
+
+    public void save(String key, String serializedEmployee){
+        Path path = Paths.get(key + ".rec");
+        try {
+            Files.write(path, serializedEmployee.getBytes());
+            System.out.println("Saved " + serializedEmployee);
+        } catch (IOException e) {
+            System.out.println("Error in saving " + e.getMessage());
+        }
+    }
+
+    public void saveAll(List<Employee> employees) {
+        for (Employee e : employees){
+            save(e.generateKey(), e.serialize());
+        }
+    }
 }

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

@@ -9,8 +9,6 @@ public static void main(String[] args) {
         List<Employee> employees = repository.findAll();
 
         // Save all
-        for (Employee e : employees){
-            e.save();
-        }
+        repository.saveAll(employees);
     }
 }