In this challenge, you are asked to bring together your knowledge of date parsing and string formatting to present a schedule of events in a clear, readable table printed to the console. You will implement a method called `formatEventTable` that takes three lists: event names, event dates, and attendee counts. The method will return a string representing a table with three columns: the event name, the date (formatted as "MMM dd, yyyy"), and the number of attendees. Each column should be properly aligned so the table is easy to read, regardless of the length of the event names or numbers. This exercise will help you practice combining date formatting with aligned table output using `String.format` and related techniques.

package com.example;

import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Test;

import java.time.LocalDate;
import java.util.Arrays;
import java.util.List;

import static org.junit.jupiter.api.Assertions.*;

public class MainTest {

    @Test
    @DisplayName("Table has correct number of rows including header and separator")
    void testRowCount() {
        List<String> names = Arrays.asList("A", "B", "C");
        List<LocalDate> dates = Arrays.asList(LocalDate.of(2024, 2, 2), LocalDate.of(2024, 3, 3), LocalDate.of(2024, 4, 4));
        List<Integer> attendees = Arrays.asList(1, 2, 3);
        String result = Main.formatEventTable(names, dates, attendees);
        int rowCount = result.split("\\n").length;
        assertEquals(5, rowCount, "Should be 2 header rows + 3 data rows");
    }

    @Test
    @DisplayName("All dates formatted as 'MMM dd, yyyy'")
    void testDateFormatting() {
        List<String> names = Arrays.asList("Event1");
        List<LocalDate> dates = Arrays.asList(LocalDate.of(2024, 12, 25));
        List<Integer> attendees = Arrays.asList(10);
        String result = Main.formatEventTable(names, dates, attendees);
        assertTrue(result.contains("Dec 25, 2024"), "Date should be formatted as 'Dec 25, 2024'");
    }

    @Test
    @DisplayName("Column widths fit longest values including headers")
    void testColumnWidths() {
        List<String> names = Arrays.asList("Short", "LongerEventName");
        List<LocalDate> dates = Arrays.asList(LocalDate.of(2024, 7, 4), LocalDate.of(2024, 8, 15));
        List<Integer> attendees = Arrays.asList(123, 5);
        String result = Main.formatEventTable(names, dates, attendees);
        String[] lines = result.split("\\n");
        String header = lines[0];
        String row = lines[2];
        assertEquals(header.indexOf('|'), row.indexOf('|'), "Column separators must align");
    }

    @Test
    @DisplayName("Attendee counts are right-aligned")
    void testAttendeeRightAlign() {
        List<String> names = Arrays.asList("E1", "E2");
        List<LocalDate> dates = Arrays.asList(LocalDate.of(2024, 1, 1), LocalDate.of(2024, 1, 2));
        List<Integer> attendees = Arrays.asList(7, 1234);
        String result = Main.formatEventTable(names, dates, attendees);
        String[] lines = result.split("\\n");
        String row1 = lines[2];
        String row2 = lines[3];
        int lastBar = row1.lastIndexOf('|');
        int lastBar2 = row2.lastIndexOf('|');
        assertTrue(row1.substring(lastBar + 1).endsWith("7") && row2.substring(lastBar2 + 1).endsWith("1234"), "Attendees column must be right-aligned");
    }

    @Test
    @DisplayName("Header and separator rows are present")
    void testHeaderAndSeparatorPresent() {
        List<String> names = Arrays.asList("Test");
        List<LocalDate> dates = Arrays.asList(LocalDate.of(2024, 5, 5));
        List<Integer> attendees = Arrays.asList(99);
        String result = Main.formatEventTable(names, dates, attendees);
        String[] lines = result.split("\\n");
        assertTrue(lines[0].contains("Event Name") && lines[1].contains("-+"), "Header and separator rows must be present");
    }
}


MainTest.java

Master the art of formatting and parsing data in Java, from string templates to numbers and dates, and learn how to create well-structured console tables. This course is designed for learners with a basic understanding of Java syntax who want to deepen their skills in data presentation and manipulation.

Explore the power of String.format() for dynamic and readable string construction in Java, including formatting numbers, aligning text, and embedding variables.

Delve into the DecimalFormat class for precise control over numeric output, including custom patterns, rounding, and parsing.

Master date parsing/formatting with LocalDate and DateTimeFormatter, and learn to create visually appealing tables in the console.

Challenge: Event Schedule Table

解答