Expensereport java refactored

README.md

@@ -138,7 +138,7 @@ To see solutions, switch to the [solutions branch](https://github.com/christianh
 
 ## Credits and License
 I first encountered the ExpenseReport example during a bootcamp at Equal Experts.
-I also have seen the ExpenseReport example being used by Robert "Uncle Bob" C. Martin.
+I also have seen the [ExpenseReport example](https://github.com/unclebob/Episode-10-ExpenseReport) being used by Robert "Uncle Bob" C. Martin.
 However, he seems to not be the original author (https://twitter.com/unclebobmartin/status/1537063143326855176?s=20&t=lh_vVb9jUQmY6PYG50974w)
 I have tried to research its origins but so far I have failed.
 If you know who has first come up with this example, please get in touch with me.

expensereport-java/src/ReportPrinter.java

@@ -0,0 +1,33 @@
+package com.nelkinda.training;
+
+import java.io.PrintStream;
+import java.util.List;
+
+public class ReportPrinter {
+    private final ExpenseFormatter formatter;
+    private final PrintStream output;
+
+    public ReportPrinter(ExpenseFormatter formatter, PrintStream output) {
+        this.formatter = formatter;
+        this.output = output;
+    }
+
+    public void printReport(List<Expense> expenses) {
+        int total = 0;
+        int mealExpenses = 0;
+
+        output.println(formatter.formatHeader());
+
+        for (Expense expense : expenses) {
+            if (expense.type == ExpenseType.DINNER || expense.type == ExpenseType.BREAKFAST) {
+                mealExpenses += expense.amount;
+            }
+
+            output.println(formatter.format(expense));
+
+            total += expense.amount;
+        }
+
+        output.println(formatter.formatFooter(mealExpenses, total));
+    }
+}

expensereport-java/src/main/java/com/nelkinda/training/Expense.java

@@ -0,0 +1,15 @@
+package com.nelkinda.training;
+
+public record Expense(ExpenseType type, int amount) {
+    public boolean isMeal() {
+        return type.isMeal();
+    }
+
+    public boolean exceedsLimit() {
+        return type.exceedsLimit(amount);
+    }
+
+    public String getName() {
+        return type.getName();
+    }
+}

expensereport-java/src/main/java/com/nelkinda/training/ExpenseFormatter.java

@@ -0,0 +1,7 @@
+package com.nelkinda.training;
+
+public interface ExpenseFormatter {
+    String format(Expense expense);
+    String formatHeader();
+    String formatFooter(int mealExpenses, int totalExpenses);
+}

expensereport-java/src/main/java/com/nelkinda/training/ExpenseReport.java

@@ -1,50 +1,15 @@
 package com.nelkinda.training;
 
-import java.util.Date;
 import java.util.List;
 
-enum ExpenseType {
-    DINNER, BREAKFAST, CAR_RENTAL
-}
-
-class Expense {
-    ExpenseType type;
-    int amount;
-}
-
 public class ExpenseReport {
-    public void printReport(List<Expense> expenses) {
-        int total = 0;
-        int mealExpenses = 0;
-
-        System.out.println("Expenses " + new Date());
+    private final ReportPrinter printer;
 
-        for (Expense expense : expenses) {
-            if (expense.type == ExpenseType.DINNER || expense.type == ExpenseType.BREAKFAST) {
-                mealExpenses += expense.amount;
-            }
-
-            String expenseName = "";
-            switch (expense.type) {
-            case DINNER:
-                expenseName = "Dinner";
-                break;
-            case BREAKFAST:
-                expenseName = "Breakfast";
-                break;
-            case CAR_RENTAL:
-                expenseName = "Car Rental";
-                break;
-            }
-
-            String mealOverExpensesMarker = expense.type == ExpenseType.DINNER && expense.amount > 5000 || expense.type == ExpenseType.BREAKFAST && expense.amount > 1000 ? "X" : " ";
-
-            System.out.println(expenseName + "\t" + expense.amount + "\t" + mealOverExpensesMarker);
-
-            total += expense.amount;
-        }
+    public ExpenseReport(ReportPrinter printer) {
+        this.printer = printer;
+    }
 
-        System.out.println("Meal expenses: " + mealExpenses);
-        System.out.println("Total expenses: " + total);
+    public void printReport(List<Expense> expenses) {
+        printer.printReport(expenses);
     }
 }

expensereport-java/src/main/java/com/nelkinda/training/ExpenseType.java

@@ -0,0 +1,58 @@
+package com.nelkinda.training;
+
+public abstract class ExpenseType {
+    public abstract String getName();
+    public abstract boolean isMeal();
+    public abstract boolean exceedsLimit(int amount);
+
+    public static final ExpenseType DINNER = new ExpenseType() {
+        @Override
+        public String getName() {
+            return "dinner";
+        }
+
+        @Override
+        public boolean isMeal() {
+            return true;
+        }
+
+        @Override
+        public boolean exceedsLimit(int amount) {
+            return amount > 5000;
+        }
+    };
+
+    public static final ExpenseType BREAKFAST = new ExpenseType() {
+        @Override
+        public String getName() {
+            return "breakfast";
+        }
+
+        @Override
+        public boolean isMeal() {
+            return true;
+        }
+
+        @Override
+        public boolean exceedsLimit(int amount) {
+            return amount > 1000;
+        }
+    };
+
+    public static final ExpenseType CAR_RENTAL = new ExpenseType() {
+        @Override
+        public String getName() {
+            return "car rental";
+        }
+
+        @Override
+        public boolean isMeal() {
+            return false;
+        }
+
+        @Override
+        public boolean exceedsLimit(int amount) {
+            return false; // No limit for car rental
+        }
+    };
+}

expensereport-java/src/main/java/com/nelkinda/training/ReportPrinter.java

@@ -0,0 +1,32 @@
+package com.nelkinda.training;
+
+import java.io.PrintStream;
+import java.util.List;
+
+public class ReportPrinter {
+    private final ExpenseFormatter formatter;
+    private final PrintStream output;
+
+    public ReportPrinter(ExpenseFormatter formatter, PrintStream output) {
+        this.formatter = formatter;
+        this.output = output;
+    }
+
+    public void printReport(List<Expense> expenses) {
+        int total = 0;
+        int mealExpenses = 0;
+
+        output.println(formatter.formatHeader());
+
+        for (Expense expense : expenses) {
+            if (expense.isMeal()) {
+                mealExpenses += expense.amount();
+            }
+
+            output.println(formatter.format(expense));
+            total += expense.amount();
+        }
+
+        output.println(formatter.formatFooter(mealExpenses, total));
+    }
+}

expensereport-java/src/main/java/com/nelkinda/training/SimpleExpenseFormatter.java

@@ -0,0 +1,20 @@
+package com.nelkinda.training;
+
+public class SimpleExpenseFormatter implements ExpenseFormatter {
+
+    @Override
+    public String format(Expense expense) {
+        String mealOverExpensesMarker = expense.exceedsLimit() ? "X" : " ";
+        return String.format("%s %d %s", expense.getName(), expense.amount(), mealOverExpensesMarker);
+    }
+
+    @Override
+    public String formatHeader() {
+        return "Expenses " + new java.util.Date();
+    }
+
+    @Override
+    public String formatFooter(int mealExpenses, int totalExpenses) {
+        return String.format("Meal expenses: %d\nTotal expenses: %d", mealExpenses, totalExpenses);
+    }
+}

expensereport-java/src/test/java/com/nelkinda/training/ExpenseReportStepDefinitions.java

@@ -0,0 +1,54 @@
+package com.nelkinda.training;
+
+import io.cucumber.java.en.Given;
+import io.cucumber.java.en.Then;
+import io.cucumber.java.en.When;
+
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+import java.text.SimpleDateFormat;
+import java.util.ArrayList;
+import java.util.Date;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class ExpenseReportStepDefinitions {
+    private List<Expense> expenses;
+    private ByteArrayOutputStream outputStream;
+    private ExpenseReport report;
+
+    @Given("the following expenses:")
+    public void the_following_expenses(List<List<String>> expenseData) {
+        expenses = new ArrayList<>();
+        for (List<String> row : expenseData) {
+            Expense expense = new Expense();
+            expense.type = ExpenseType.valueOf(row.get(0).toUpperCase());
+            expense.amount = Integer.parseInt(row.get(1));
+            expenses.add(expense);
+        }
+    }
+
+    @When("printing the report")
+    public void printing_the_report() {
+        outputStream = new ByteArrayOutputStream();
+        PrintStream originalOut = System.out;
+        System.setOut(new PrintStream(outputStream));
+
+        ExpenseFormatter formatter = new SimpleExpenseFormatter();
+        ReportPrinter printer = new ReportPrinter(formatter, System.out);
+        report = new ExpenseReport(printer);
+        report.printReport(expenses);
+
+        System.setOut(originalOut);
+    }
+
+    @Then("the report MUST look like this:")
+    public void the_report_must_look_like_this(String expectedOutput) {
+        String actualOutput = outputStream.toString().trim();
+        String currentDate = new SimpleDateFormat("EEE MMM dd HH:mm:ss zzz yyyy").format(new Date());
+        String expectedWithDate = expectedOutput.replace("<current date>", currentDate).trim();
+
+        assertEquals(expectedWithDate, actualOutput);
+    }
+}

expensereport-java/src/test/resources/ExpenseReport.feature

@@ -0,0 +1,31 @@
+Feature: ExpenseReport
+
+  Scenario: single breakfast expense
+    Given the following expenses:
+      | Type      | Amount   | 
+      | BREAKFAST | 100      |
+    When printing the report
+    Then the report MUST look like this:
+      """
+      Expenses <current date>
+      breakfast 100
+      Meal expenses: 100
+      Total expenses: 100
+      """
+
+  Scenario: multiple expenses with some exceeding limits
+    Given the following expenses:
+      | Type       | Amount |
+      | BREAKFAST  | 1200   |
+      | DINNER     | 6000   |
+      | CAR_RENTAL | 3000   |
+    When printing the report
+    Then the report MUST look like this:
+      """
+      Expenses <current date>
+      breakfast 1200 X
+      dinner 6000 X
+      car rental 3000
+      Meal expenses: 7200
+      Total expenses: 10200
+      """