Jean-Luc Makiola
83643a192f
Walking skeleton through Swing GUI: YAML-driven world (4 rooms, 4 items, 1 NPC), HashMap command dispatch with parser, three-tier item hierarchy (readable / switchable / plain), and end-to-end NPC give/receive flow. 67 tests green.
128 lines
3.6 KiB
Markdown
128 lines
3.6 KiB
Markdown
# Befehle
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Command-Pattern mit Registry — passt zum Aufgaben-Tipp „switch, if-else, HashMap" und macht die HashMap-Variante explizit.
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## Interface
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```java
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public interface Command {
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/** Wird vom Parser nach Tokenisierung aufgerufen. */
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void execute(GameContext ctx, List<String> args);
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/** Short help text for the 'help' command. */
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String help();
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}
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```
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## Registry
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```java
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public class CommandRegistry {
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private final Map<String, Command> commands = new HashMap<>();
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public void register(Command cmd, String... names) {
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for (String n : names) {
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commands.put(n.toLowerCase(), cmd);
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}
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}
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public Optional<Command> find(String verb) {
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return Optional.ofNullable(commands.get(verb.toLowerCase()));
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}
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}
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```
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**Aliase per Mehrfach-Registrierung:**
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```java
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registry.register(new GoCommand(), "go", "move");
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registry.register(new TakeCommand(), "take", "pick");
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```
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## Parser
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Einfacher tokenisierender Parser. Erst-Token = Verb, Rest = Argumente.
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Spezialfall: Präpositionen / Artikel wegfiltern, damit `go to north` und `go north` beide funktionieren.
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```java
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public record ParsedCommand(String verb, List<String> args) {}
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public class CommandParser {
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private static final Set<String> FILLERS = Set.of("to", "with", "at", "the", "a", "an");
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public ParsedCommand parse(String input) {
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String[] tokens = input.trim().toLowerCase().split("\\s+");
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if (tokens.length == 0 || tokens[0].isEmpty()) {
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return new ParsedCommand("", List.of());
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}
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String verb = tokens[0];
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List<String> args = Arrays.stream(tokens, 1, tokens.length)
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.filter(t -> !FILLERS.contains(t))
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.toList();
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return new ParsedCommand(verb, args);
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}
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}
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```
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## Befehlsliste (Pflicht + Optional)
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| Verb | Aliase | Wirkung | Quelle |
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|---|---|---|---|
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| `go <direction>` | `move`, `walk` | Spieler wechselt Raum | Pflicht |
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| `take <item>` | `pick`, `get` | Item aus Raum ins Inventar | Pflicht |
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| `drop <item>` | `put` | Item aus Inventar in Raum | sinnvoll |
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| `use <item>` | — | Item-spezifische Aktion | Pflicht |
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| `read <item>` | — | Spezialfall von use für `readable` | Pflicht |
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| `inventory` | `inv`, `i` | Inventar anzeigen | sinnvoll |
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| `look` | `l` | Raumbeschreibung wiederholen | sinnvoll |
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| `examine <item>` | `x` | Item-Beschreibung anzeigen | sinnvoll |
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| `talk <npc>` | `speak` | NPC-Greeting ausgeben | NPC-Bonus |
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| `give <item> <npc>` | — | Item übergeben, Reaktion auslösen | NPC-Bonus |
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| `help` | `?` | Befehlsübersicht | sinnvoll |
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| `quit` | `exit` | Spiel beenden | sinnvoll |
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## Behandlung unbekannter Befehle
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```java
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parser.parse(input);
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registry.find(parsed.verb())
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.ifPresentOrElse(
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cmd -> cmd.execute(ctx, parsed.args()),
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() -> ctx.io().write("I don't understand '" + parsed.verb() + "'. Type 'help'.")
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);
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```
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## GameContext
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Wird allen Commands gereicht, kapselt was sie ändern dürfen:
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```java
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public class GameContext {
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private final World world;
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private final Player player;
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private final GameIO io;
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// Lombok @Getter, kein Setter
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}
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```
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So vermeidest du, dass jeder Command 5 Konstruktor-Parameter braucht.
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## Tests
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Pro Command ein Testfall, der `GameContext` mit Mockito mockt (oder als Fake-IO baut):
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```java
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@Test
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void goCommand_movesPlayerToConnectedRoom() {
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Room kitchen = ...; Room hallway = ...;
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kitchen.getExits().put(Direction.NORTH, hallway);
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Player p = new Player(kitchen, 0);
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GameContext ctx = new GameContext(world, p, new TestIO());
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new GoCommand().execute(ctx, List.of("north"));
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assertThat(p.getCurrentRoom()).isEqualTo(hallway);
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}
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```
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