patternjavaMinor

Family finances - tracking and reporting

Submitted by: @import:stackexchange-codereview·Mar 10, 2026·

Viewed 0 times

trackingreportingfinancesandfamily

Problem

I am looking for clean way to accumulate amounts within a input dataset. In this example, there are 18 rows of data, and the output is a 3 rows of data, accumulated by Key, by ExpenseType.

My biggest concern is whether hashMap is the correct utility for this, or if there is an easier/cleaner way.

FamilyExpenseProcessor.java:

```
import java.math.BigDecimal;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;

public class FamilyExpenseProcessor {

enum ExpenseType {
Grocery, Entertainment,Transportation
}

public static void main(String[] args) {

Map feHashMap = new HashMap<>();

accumulate(feHashMap, "Jeffersons",ExpenseType.Entertainment, new BigDecimal(5.00));
accumulate(feHashMap, "Jetsons", ExpenseType.Entertainment, new BigDecimal(10.00));
accumulate(feHashMap, "Johnsons", ExpenseType.Entertainment, new BigDecimal(15.00));

accumulate(feHashMap, "Jeffersons",ExpenseType.Entertainment, new BigDecimal(20.00));
accumulate(feHashMap, "Jetsons", ExpenseType.Entertainment, new BigDecimal(25.00));
accumulate(feHashMap, "Johnsons", ExpenseType.Entertainment, new BigDecimal(30.00));

accumulate(feHashMap, "Jeffersons",ExpenseType.Grocery, new BigDecimal(35.00));
accumulate(feHashMap, "Jetsons", ExpenseType.Grocery, new BigDecimal(40.00));
accumulate(feHashMap, "Johnsons", ExpenseType.Grocery, new BigDecimal(45.00));

accumulate(feHashMap, "Jeffersons",ExpenseType.Grocery, new BigDecimal(50.00));
accumulate(feHashMap, "Jetsons", ExpenseType.Grocery, new BigDecimal(55.00));
accumulate(feHashMap, "Johnsons", ExpenseType.Grocery, new BigDecimal(60.00));

accumulate(feHashMap, "Jeffersons",ExpenseType.Transportation, new BigDecimal(15.00));
accumulate(feHashMap, "Jetsons", ExpenseType.Transportation, new BigDecimal(20.00));
accumulate(feHashMap, "Johnsons", ExpenseType.Tran

Solution

I would suggest adding a method addExpense(ExpenseType expenseType, BigDecimal amount) to FamilyExpense. That way your accumulate method could look like this:

private static void accumulate(Map expenses, String key, ExpenseType expenseType, BigDecimal amount) {
  if (expenses.containsKey(key)) {
    expenses.get(key).addExpense(expenseType, amount);
    return;
  }

  FamilyExpense expense =  new FamilyExpense();
  expense.addExpense(expenseType, amount);
  expenses.put(key, expense);
}

You can also iterate through the entries using entrySet:

for (Map.Entry entry : entries.entrySet()) {
  ...
}

Code Snippets

private static void accumulate(Map<String, FamilyExpense> expenses, String key, ExpenseType expenseType, BigDecimal amount) {
  if (expenses.containsKey(key)) {
    expenses.get(key).addExpense(expenseType, amount);
    return;
  }

  FamilyExpense expense =  new FamilyExpense();
  expense.addExpense(expenseType, amount);
  expenses.put(key, expense);
}

for (Map.Entry<String, FamilyExpense> entry : entries.entrySet()) {
  ...
}

Context

StackExchange Code Review Q#59759, answer score: 2

Revisions (0)

No revisions yet.