pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>lol.gilliard</groupId>
    <artifactId>jbcn19-twilio-prizedraw</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.release>11</maven.compiler.release>
    </properties>

    <dependencies>
        <dependency>
            <groupId>com.twilio.sdk</groupId>
            <artifactId>twilio</artifactId>
            <version>7.37.4</version>
        </dependency>
    </dependencies>

</project>

TwilioRaffle.java

package prizedraw;

import com.twilio.Twilio;
import com.twilio.base.ResourceSet;
import com.twilio.rest.api.v2010.account.Message;
import com.twilio.type.PhoneNumber;
import org.joda.time.DateTime;

import java.util.Collections;
import java.util.stream.Collectors;
import java.util.stream.StreamSupport;

import static java.util.stream.Collectors.toList;

public class TwilioRaffle {

    private static final DateTime DRAW_START = new DateTime(2019,5,27,9,0);
    private static final DateTime DRAW_END   = new DateTime(2019,5,28,16,30);

    private static final int NUMBER_OF_WINNERS = 3;
    private static final PhoneNumber CONTEST_NUMBER = new PhoneNumber(System.getenv("CONTEST_NUMBER"));

    private static final String CONGRATULATIONS_YOU_WON_MESSAGE = "\uD83C\uDF89 Congratulations - you won a prize in the Twilio Prize Draw at JBcnConf \uD83C\uDF89\n\n" +
        "Head to the Twilio booth and show us this message to collect your prize \uD83C\uDF8A - we will give them out in the order you arrive so don't delay.";


    public static void main(String[] args) {

        Twilio.init(System.getenv("ACCOUNT_SID"), System.getenv("AUTH_TOKEN"));
        ResourceSet<Message> allMessages = Message.reader().setTo(CONTEST_NUMBER).read();

        StreamSupport.stream(allMessages.spliterator(), false)           // Create a java.util.stream.Stream
            .filter( m -> m.getDateSent().isAfter(DRAW_START))           // Filter out entries which were too early...
            .filter( m -> m.getDateSent().isBefore(DRAW_END))            // ...or too late.
            .map(Message::getFrom)                                       // Take the FromNumber from each message.
            .distinct()                                                  // Remove duplicates, then...
            .collect(Collectors.collectingAndThen(toList(),              // ...collect into a list so that...
                list -> {
                    Collections.shuffle(list);                           // ...we can shuffle the order.
                    return list.stream();
                }))
            .limit(NUMBER_OF_WINNERS)                                    // Make sure we don't select too many winners
            .forEach( winner -> {
                Message.creator(
                    winner, CONTEST_NUMBER,
                    CONGRATULATIONS_YOU_WON_MESSAGE).create();           // Send a message to all the winners!
            });
    }
}