Currency Converter Application (Java)

An application that can convert a user-defined amount in a source currency to a destination currency. This application gives the user the option to convert currencies in the given, hard-coded class, or by using the live (daily-refreshed) exchange rates fetched from ExchangeRate API. The application has been implemented as both a command-line application and with a Swing GUI.

Description

Currency Converter

CurrencyConverter interface

The CurrencyConverter interface includes three methods:

• double convertCurrency(String sourceCurrencyCode, String destinationCurrencyCode, double amount): This method accepts a source currency code, a destination currency code, and an amount. It will return the converted amount.
• String[] getCurrencyCodes(): This method returns an array of available currency codes
• double getExchangeRate(String sourceCurrencyCode, String destinationCurrencyCode): This method returns the exchange rate between the provided currencies.

BasicCurrencyConverter class

The BasicCurrenciesConverter class implements the 'CurrencyConverter' interface.

Currency Converter (API)

The CurrenciesAPI class has the following method:

• double getCurrencyConversionA(String source, String destination, double amount): This method excepts a source currency code, a destination currency code, and an amount. It will return the converted amount from the from ExchangeRate-API, using exchange rates that update once per day.

Demo

Prerequisites

Running the Project

This project uses the [Java][1] programming language.

Before getting started, ensure you have Java 17 LTS (or higher) installed locally. The following commands should output the version of Java installed.

$ javac -version

javac 17.0.4

$ java -version

openjdk version "17.0.4" 2022-07-19 LTS
OpenJDK Runtime Environment Zulu17.36+13-CA (build 17.0.4+8-LTS)
OpenJDK 64-Bit Server VM Zulu17.36+13-CA (build 17.0.4+8-LTS, mixed mode, sharing)

Using the API option

Before using the API option of the Currency Converter, you need to obtain an API key from ExchangeRate API. You will use this API key when initializing the CurrenciesAPI object.

How to Install and Run this project

Testing

To ensure that the API method functions correctly, you can run the included unit test which uses JUnit and Mockito.