Keystream parser

IVKeystream.txt

Hinweis IV:050607 bedeutet IV[0]=05,IV[1]=06,IV[2]=07
IV: 02 01 C4  Schlüsselstrom: 02
IV: 03 01 C4  Schlüsselstrom: F8
IV: 03 FF 15  Schlüsselstrom: E0
IV: 03 FF 78  Schlüsselstrom: 54
IV: 02 01 A3  Schlüsselstrom: FC
IV: 02 01 F3  Schlüsselstrom: 73
IV: 03 FF 99  Schlüsselstrom: AA
IV: 02 01 0C  Schlüsselstrom: CD
IV: 02 01 43  Schlüsselstrom: A1
IV: 02 FF 27  Schlüsselstrom: 2A
IV: 03 01 FA  Schlüsselstrom: 2E
IV: 03 FF 08  Schlüsselstrom: 0A
IV: 03 FF 84  Schlüsselstrom: 4F
IV: 02 FF 9F  Schlüsselstrom: C9
IV: 03 01 CC  Schlüsselstrom: 27
IV: 03 01 63  Schlüsselstrom: 95
IV: 02 FF 5F  Schlüsselstrom: 38
IV: 03 01 8D  Schlüsselstrom: DA
IV: 03 FF FC  Schlüsselstrom: 6F
IV: 03 FF 8E  Schlüsselstrom: EC
IV: 03 01 AA  Schlüsselstrom: D8
IV: 02 FF CF  Schlüsselstrom: E0
IV: 02 FF E2  Schlüsselstrom: 91
IV: 02 01 34  Schlüsselstrom: 4E

Main.java

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Objects;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

@SuppressWarnings("WeakerAccess")
class IVKeystreamEntry {
    int first, second, third;
    int key;

    IVKeystreamEntry() {
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        IVKeystreamEntry that = (IVKeystreamEntry) o;
        return first == that.first &&
                second == that.second &&
                third == that.third &&
                key == that.key;
    }

    @Override
    public int hashCode() {

        return Objects.hash(first, second, third, key);
    }

    @Override
    public String toString() {
        return "IVKeystreamEntry{" +
                "first=" + first +
                ", second=" + second +
                ", third=" + third +
                ", key=" + key +
                '}';
    }
}

public class Main {
    private static final Pattern linePattern = Pattern.compile("IV: (?<first>[0-9A-Z]+)\\s(?<second>[0-9A-Z]+)\\s(?<third>[0-9A-Z]+)\\s+Schlüsselstrom:\\s(?<key>[0-9A-Z]+)");

    public static void main(String[] args) throws IOException {
        @SuppressWarnings("SpellCheckingInspection") File file = new File("IVkeystream.txt");

        BufferedReader reader = new BufferedReader(new FileReader(file));
        reader.readLine();
        String line;
        List<IVKeystreamEntry> entryList = new ArrayList<>();
        try (reader) {
            line = reader.readLine();
            while (line != null) {
                line = reader.readLine();
                entryList.add(mapToEntry(line));
            }
        } catch (IOException e) {
            e.printStackTrace();
        }

        entryList.stream()
                .filter(Objects::nonNull)
                .filter(entry -> entry.first == 3 && entry.second == 255)
                .map(IVKeystreamEntry::toString)
                .reduce((sum, item) -> sum + '\n' + item)
                .ifPresent(System.out::println);
    }

    private static IVKeystreamEntry mapToEntry(String line) {
        if (line == null) {
            return null;
        }
        Matcher matcher = linePattern.matcher(line);
        if (!matcher.find()) {
            return null;
        }
        final IVKeystreamEntry entry = new IVKeystreamEntry();

        Arrays.asList(entry.getClass().getDeclaredFields())
                .forEach(field -> {
                    try {
                        field.setInt(entry, Integer.valueOf(matcher.group(field.getName()), 16));
                    } catch (IllegalAccessException e) {
                        e.printStackTrace();
                    }
                });
        return entry;
    }
}