Java stream reduce

Java/java-stream-reduce/ExpenseTracker.java

@@ -0,0 +1,29 @@
+import java.util.Arrays;
+import java.util.List;
+class Expense {
+   String category;
+   private double expense;
+   Expense(String _category, double _expense) {
+       this.category = _category;
+       this.expense = _expense;
+   }
+   double getExpense() {
+       return expense;
+   }
+   String getCategory() {
+       return category;
+   }
+}
+
+public class ExpenseTracker {
+   public static void main(String[] args) {
+       List<Expense> expenseList = Arrays.asList(new Expense("fuel", 200), new Expense("grocery", 1000), new Expense("rent", 500), new Expense("outdoor", 560.5));
+       double totalExpense = expenseList.stream().reduce(0.0, (result, current) -> result + current.getExpense(), Double::sum);
+       Expense highestExpense = expenseList.stream().reduce((result, current) -> result.getExpense() > current.getExpense() ? result : current).orElse(null);
+       double lowestExpenseAmount = expenseList.stream().map(Expense::getExpense).reduce(Double.MAX_VALUE, (result, current) -> result < current ? result : current);
+
+       System.out.println("Total expense : " + totalExpense);
+       System.out.println("Highest expense category : " + highestExpense.getCategory() + " expense : " + highestExpense.getExpense());
+       System.out.println("Lowest expense : " + lowestExpenseAmount);
+   }
+}