money/src/main/java/com/iluwatar/App.java - master - githubmirror/java-design-patterns

money/src/main/java/com/iluwatar/App.java
92 строки4 KB
Ilkka Seppälä
deps: Refactor dependencies (#3224)
29 мар 2025, 20:34
29 мар 2025, 20:340ca162a
/*
 * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
 *
 * The MIT License
 * Copyright © 2014-2022 Ilkka Seppälä
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package com.iluwatar;

import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * The `App` class demonstrates the functionality of the {@link Money} class, which encapsulates
 * monetary values and their associated currencies. It showcases operations like addition,
 * subtraction, multiplication, and currency conversion, while ensuring validation and immutability.
 *
 * <p>Through this example, the handling of invalid operations (e.g., mismatched currencies or
 * invalid inputs) is demonstrated using custom exceptions. Logging is used for transparency.
 *
 * <p>This highlights the practical application of object-oriented principles such as encapsulation
 * and validation in a financial context.
 */
public class App {

  // Initialize the logger
  private static final Logger logger = Logger.getLogger(App.class.getName());

  /**
   * Program entry point.
   *
   * @param args command line args
   */
  public static void main(String[] args) {
    // Create instances of Money
    Money usdAmount1 = new Money(50.00, "USD");
    Money usdAmount2 = new Money(20.00, "USD");

    // Demonstrate addition
    try {
      usdAmount1.addMoney(usdAmount2);
      logger.log(Level.INFO, "Sum in USD: {0}", usdAmount1.getAmount());
    } catch (CannotAddTwoCurrienciesException e) {
      logger.log(Level.SEVERE, "Error adding money: {0}", e.getMessage());
    }

    // Demonstrate subtraction
    try {
      usdAmount1.subtractMoney(usdAmount2);
      logger.log(Level.INFO, "Difference in USD: {0}", usdAmount1.getAmount());
    } catch (CannotSubtractException e) {
      logger.log(Level.SEVERE, "Error subtracting money: {0}", e.getMessage());
    }

    // Demonstrate multiplication
    try {
      usdAmount1.multiply(2);
      logger.log(Level.INFO, "Multiplied Amount in USD: {0}", usdAmount1.getAmount());
    } catch (IllegalArgumentException e) {
      logger.log(Level.SEVERE, "Error multiplying money: {0}", e.getMessage());
    }

    // Demonstrate currency conversion
    try {
      double exchangeRateUsdToEur = 0.85; // Example exchange rate
      usdAmount1.exchangeCurrency("EUR", exchangeRateUsdToEur);
      logger.log(
          Level.INFO,
          "USD converted to EUR: {0} {1}",
          new Object[] {usdAmount1.getAmount(), usdAmount1.getCurrency()});
    } catch (IllegalArgumentException e) {
      logger.log(Level.SEVERE, "Error converting currency: {0}", e.getMessage());
    }
  }
}