ch08_SchedulingMeetingsAPI.java

import java.util.*;

public class ch08_SchedulingMeetingsAPI {
    /*
     * PREREQUISITE: unsafe functions that we'll use to simulate external API calls
     *
     * They have *ApiCall suffix:
     * - call an external service to all current calendar entries for a given name.
     * - call an external service to create a new meeting in $name's calendar.
     *
     * These are not an example of FP code, but a simplistic simulation of how some an external API may behave.
     * Note that we can't change an external API and need to work with how it works (so no change in these functions!).
     * Note that we don't consider any security pitfalls her for the sake of a cleaner presentation.
     * Note that most likely this should return a raw JSON, not a List[Meeting], but it doesn't matter here, plus
     * we already know how to deal with parsing.
     */
    static List<MeetingTime> calendarEntriesApiCall(String name) {
        Random rand = new Random();
        if (rand.nextFloat() < 0.25) throw new RuntimeException("Connection error");
        if (name.equals("Alice")) return List.of(new MeetingTime(8, 10), new MeetingTime(11, 12));
        else if (name.equals("Bob")) return List.of(new MeetingTime(9, 10));
        else { // random meeting starting between 8 and 12, and ending between 13 and 16
            return List.of(new MeetingTime(rand.nextInt(5) + 8, rand.nextInt(4) + 13));
        }
    }

    static void createMeetingApiCall(List<String> names, MeetingTime meetingTime) {
        // Note that it also may fail fail, similarly to calendarEntriesApiCall, but we don't show it in the book:
        // Random rand = new Random();
        // if(rand.nextFloat() < 0.25) throw new RuntimeException("💣");
        System.out.printf("SIDE-EFFECT: Created meeting %s for %s\n", meetingTime, Arrays.toString(names.toArray()));
    }
}