refactoring : long function - replace function with command

refactoring/src/main/java/com/example/refactoring/_03_long_function/_10_replace_function_with_command/Participant.java

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+package com.example.refactoring._03_long_function._10_replace_function_with_command;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public record Participant(String username, Map<Integer, Boolean> homework) {
+    public Participant(String username) {
+        this(username, new HashMap<>());
+    }
+
+    public double getRate(double total) {
+        long count = this.homework.values().stream()
+                .filter(v -> v == true)
+                .count();
+        return count * 100 / total;
+    }
+
+    public void setHomeworkDone(int index) {
+        this.homework.put(index, true);
+    }
+
+}
+

refactoring/src/main/java/com/example/refactoring/_03_long_function/_10_replace_function_with_command/StudyDashboard.java

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+package com.example.refactoring._03_long_function._10_replace_function_with_command;
+
+import org.kohsuke.github.GHIssue;
+import org.kohsuke.github.GHIssueComment;
+import org.kohsuke.github.GHRepository;
+import org.kohsuke.github.GitHub;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+public class StudyDashboard {
+
+    private final int totalNumberOfEvents;
+
+    public StudyDashboard(int totalNumberOfEvents) {
+        this.totalNumberOfEvents = totalNumberOfEvents;
+    }
+
+    public static void main(String[] args) throws IOException, InterruptedException {
+        StudyDashboard studyDashboard = new StudyDashboard(15);
+        studyDashboard.print();
+    }
+
+    private Participant findParticipant(String username, List<Participant> participants) {
+        Participant participant = null;
+        if (participants.stream().noneMatch(p -> p.username().equals(username))) {
+            participant = new Participant(username);
+            participants.add(participant);
+        } else {
+            participant = participants.stream().filter(p -> p.username().equals(username)).findFirst().orElseThrow();
+        }
+        return participant;
+    }
+
+    private void print() throws IOException, InterruptedException {
+        GitHub gitHub = GitHub.connect();
+        GHRepository repository = gitHub.getRepository("whiteship/live-study");
+        List<Participant> participants = new CopyOnWriteArrayList<>();
+
+        ExecutorService service = Executors.newFixedThreadPool(8);
+        CountDownLatch latch = new CountDownLatch(totalNumberOfEvents);
+
+        for (int index = 1 ; index <= totalNumberOfEvents ; index++) {
+            int eventId = index;
+            service.execute(new Runnable() {
+                @Override
+                public void run() {
+                    try {
+                        GHIssue issue = repository.getIssue(eventId);
+                        List<GHIssueComment> comments = issue.getComments();
+
+                        for (GHIssueComment comment : comments) {
+                            Participant participant = findParticipant(comment.getUserName(), participants);
+                            participant.setHomeworkDone(eventId);
+                        }
+
+                        latch.countDown();
+                    } catch (IOException e) {
+                        throw new IllegalArgumentException(e);
+                    }
+                }
+            });
+        }
+
+        latch.await();
+        service.shutdown();
+
+        new StudyPrinter(this.totalNumberOfEvents, participants).execute();
+    }
+
+}
+

refactoring/src/main/java/com/example/refactoring/_03_long_function/_10_replace_function_with_command/StudyPrinter.java

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+package com.example.refactoring._03_long_function._10_replace_function_with_command;
+
+import java.io.FileWriter;
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.util.Comparator;
+import java.util.List;
+
+/**
+ * 함수를 독립적인 객체로 만들어서 사용 (복잡한 기능을 구현 할 때 여러 메소드를 추가하여 사용할 수 있다.)
+ */
+public class StudyPrinter {
+
+    private final int totalNumberOfEvents;
+
+    private final List<Participant> participants;
+
+    public StudyPrinter(int totalNumberOfEvents, List<Participant> participants) {
+        this.totalNumberOfEvents = totalNumberOfEvents;
+        this.participants = participants;
+    }
+
+    public void execute() throws IOException {
+        try (FileWriter fileWriter = new FileWriter("participants.md");
+             PrintWriter writer = new PrintWriter(fileWriter)) {
+            this.participants.sort(Comparator.comparing(Participant::username));
+
+            writer.print(header(this.participants.size()));
+
+            this.participants.forEach(p -> {
+                String markdownForHomework = getMarkdownForParticipant(p);
+                writer.print(markdownForHomework);
+            });
+        }
+    }
+
+
+    private String getMarkdownForParticipant(Participant p) {
+        return String.format("| %s %s | %.2f%% |\n", p.username(), checkMark(p, this.totalNumberOfEvents),
+                p.getRate(this.totalNumberOfEvents));
+    }
+
+    /**
+     * | 참여자 (420) | 1주차 | 2주차 | 3주차 | 참석율 |
+     * | --- | --- | --- | --- | --- |
+     */
+    private String header(int totalNumberOfParticipants) {
+        StringBuilder header = new StringBuilder(String.format("| 참여자 (%d) |", totalNumberOfParticipants));
+
+        for (int index = 1; index <= this.totalNumberOfEvents; index++) {
+            header.append(String.format(" %d주차 |", index));
+        }
+        header.append(" 참석율 |\n");
+
+        header.append("| --- ".repeat(Math.max(0, this.totalNumberOfEvents + 2)));
+        header.append("|\n");
+
+        return header.toString();
+    }
+
+    /**
+     * |:white_check_mark:|:white_check_mark:|:white_check_mark:|:x:|
+     */
+    private String checkMark(Participant p, int totalEvents) {
+        StringBuilder line = new StringBuilder();
+        for (int i = 1 ; i <= totalEvents ; i++) {
+            if(p.homework().containsKey(i) && p.homework().get(i)) {
+                line.append("|:white_check_mark:");
+            } else {
+                line.append("|:x:");
+            }
+        }
+        return line.toString();
+    }
+
+}