Expand GameRule API

2 files changed, 252 insertions, 2 deletions

diff --git a/src/main/java/org/bukkit/GameRule.java b/src/main/java/org/bukkit/GameRule.java
new file mode 100644
index 00000000..958fe3ea
--- /dev/null
+++ b/src/main/java/org/bukkit/GameRule.java
@@ -0,0 +1,217 @@
+package org.bukkit;
+
+import com.google.common.base.Preconditions;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * GameRules dictate certain behavior within Minecraft itself
+ * <br>
+ * For more information please visit the
+ * <a href="https://minecraft.gamepedia.com/Commands/gamerule">Minecraft
+ * Wiki</a>
+ */
+public final class GameRule<T> {
+
+    private static Map<String, GameRule<?>> gameRules = new HashMap<>();
+    // Boolean rules
+    /**
+     * Toggles the announcing of advancements.
+     */
+    public static final GameRule<Boolean> ANNOUNCE_ADVANCEMENTS = new GameRule<>("announceAdvancements", Boolean.class);
+
+    /**
+     * Whether command blocks should notify admins when they perform commands.
+     */
+    public static final GameRule<Boolean> COMMAND_BLOCK_OUTPUT = new GameRule<>("commandBlockOutput", Boolean.class);
+
+    /**
+     * Whether the server should skip checking player speed when the player is
+     * wearing elytra.
+     */
+    public static final GameRule<Boolean> DISABLE_ELYTRA_MOVEMENT_CHECK = new GameRule<>("disableElytraMovementCheck", Boolean.class);
+
+    /**
+     * Whether time progresses from the current moment.
+     */
+    public static final GameRule<Boolean> DO_DAYLIGHT_CYCLE = new GameRule<>("doDaylightCycle", Boolean.class);
+
+    /**
+     * Whether entities that are not mobs should have drops.
+     */
+    public static final GameRule<Boolean> DO_ENTITY_DROPS = new GameRule<>("doEntityDrops", Boolean.class);
+
+    /**
+     * Whether fire should spread and naturally extinguish.
+     */
+    public static final GameRule<Boolean> DO_FIRE_TICK = new GameRule<>("doFireTick", Boolean.class);
+
+    /**
+     * Whether players should only be able to craft recipes they've unlocked
+     * first.
+     */
+    public static final GameRule<Boolean> DO_LIMITED_CRAFTING = new GameRule<>("doLimitedCrafting", Boolean.class);
+
+    /**
+     * Whether mobs should drop items.
+     */
+    public static final GameRule<Boolean> DO_MOB_LOOT = new GameRule<>("doMobLoot", Boolean.class);
+
+    /**
+     * Whether mobs should naturally spawn.
+     */
+    public static final GameRule<Boolean> DO_MOB_SPAWNING = new GameRule<>("doMobSpawning", Boolean.class);
+
+    /**
+     * Whether blocks should have drops.
+     */
+    public static final GameRule<Boolean> DO_TILE_DROPS = new GameRule<>("doTileDrops", Boolean.class);
+
+    /**
+     * Whether the weather will change from the current moment.
+     */
+    public static final GameRule<Boolean> DO_WEATHER_CYCLE = new GameRule<>("doWeatherCycle", Boolean.class);
+
+    /**
+     * Whether the player should keep items in their inventory after death.
+     */
+    public static final GameRule<Boolean> KEEP_INVENTORY = new GameRule<>("keepInventory", Boolean.class);
+
+    /**
+     * Whether to log admin commands to server log.
+     */
+    public static final GameRule<Boolean> LOG_ADMIN_COMMANDS = new GameRule<>("logAdminCommands", Boolean.class);
+
+    /**
+     * Whether mobs can pick up items or change blocks.
+     */
+    public static final GameRule<Boolean> MOB_GRIEFING = new GameRule<>("mobGriefing", Boolean.class);
+
+    /**
+     * Whether players can regenerate health naturally through their hunger bar.
+     */
+    public static final GameRule<Boolean> NATURAL_REGENERATION = new GameRule<>("naturalRegeneration", Boolean.class);
+
+    /**
+     * Whether the debug screen shows all or reduced information.
+     */
+    public static final GameRule<Boolean> REDUCED_DEBUG_INFO = new GameRule<>("reducedDebugInfo", Boolean.class);
+
+    /**
+     * Whether the feedback from commands executed by a player should show up in
+     * chat. Also affects the default behavior of whether command blocks store
+     * their output text.
+     */
+    public static final GameRule<Boolean> SEND_COMMAND_FEEDBACK = new GameRule<>("sendCommandFeedback", Boolean.class);
+
+    /**
+     * Whether a message appears in chat when a player dies.
+     */
+    public static final GameRule<Boolean> SHOW_DEATH_MESSAGES = new GameRule<>("showDeathMessages", Boolean.class);
+
+    /**
+     * Whether players in spectator mode can generate chunks.
+     */
+    public static final GameRule<Boolean> SPECTATORS_GENERATE_CHUNKS = new GameRule<>("spectatorsGenerateChunks", Boolean.class);
+
+    // Numerical rules
+    /**
+     * How often a random block tick occurs (such as plant growth, leaf decay,
+     * etc.) per chunk section per game tick. 0 will disable random ticks,
+     * higher numbers will increase random ticks.
+     */
+    public static final GameRule<Integer> RANDOM_TICK_SPEED = new GameRule<>("randomTickSpeed", Integer.class);
+
+    /**
+     * The number of blocks outward from the world spawn coordinates that a
+     * player will spawn in when first joining a server or when dying without a
+     * spawnpoint.
+     */
+    public static final GameRule<Integer> SPAWN_RADIUS = new GameRule<>("spawnRadius", Integer.class);
+
+    /**
+     * The maximum number of other pushable entities a mob or player can push,
+     * before taking suffocation damage.
+     * <br>
+     * Setting to 0 disables this rule.
+     */
+    public static final GameRule<Integer> MAX_ENTITY_CRAMMING = new GameRule<>("maxEntityCramming", Integer.class);
+
+    /**
+     * Determines the number at which the chain of command blocks act as a
+     * "chain."
+     * <br>
+     * This is the maximum amount of command blocks that can be activated in a
+     * single tick from a single chain.
+     */
+    public static final GameRule<Integer> MAX_COMMAND_CHAIN_LENGTH = new GameRule<>("maxCommandChainLength", Integer.class);
+
+    // All GameRules instantiated above this for organizational purposes
+    private final String name;
+    private final Class<T> type;
+
+    private GameRule(String name, Class<T> clazz) {
+        Preconditions.checkNotNull(name, "GameRule name cannot be null");
+        Preconditions.checkNotNull(clazz, "GameRule type cannot be null");
+        Preconditions.checkArgument(clazz == Boolean.class || clazz == Integer.class, "Must be of type Boolean or Integer. Found %s ", clazz.getName());
+        this.name = name;
+        this.type = clazz;
+        gameRules.put(name, this);
+    }
+
+    /**
+     * Get the name of this GameRule.
+     *
+     * @return the name of this GameRule
+     */
+    public String getName() {
+        return name;
+    }
+
+    /**
+     * Get the type of this rule.
+     *
+     * @return the rule type; Integer or Boolean
+     */
+    public Class<T> getType() {
+        return type;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (!(obj instanceof GameRule)) {
+            return false;
+        }
+        GameRule<?> other = (GameRule<?>) obj;
+        return this.getName().equals(other.getName()) && this.getType() == other.getType();
+    }
+
+    @Override
+    public String toString() {
+        return "GameRule{" + "key=" + name + ", type=" + type + '}';
+    }
+
+    /**
+     * Get a {@link GameRule} by its name.
+     *
+     * @param rule the name of the GameRule
+     * @return the {@link GameRule} or null if no GameRule matches the given
+     * name
+     */
+    public static GameRule<?> getByName(String rule) {
+        Preconditions.checkNotNull(rule, "Rule cannot be null");
+        return gameRules.get(rule);
+    }
+
+    /**
+     * Get an immutable collection of {@link GameRule}s.
+     *
+     * @return an immutable collection containing all registered GameRules.
+     */
+    public static GameRule<?>[] values() {
+        return gameRules.values().toArray(new GameRule<?>[gameRules.size()]);
+    }
+}
diff --git a/src/main/java/org/bukkit/World.java b/src/main/java/org/bukkit/World.java
index ecfdecaa..2237039b 100644
--- a/src/main/java/org/bukkit/World.java
+++ b/src/main/java/org/bukkit/World.java
@@ -1205,9 +1205,9 @@ public interface World extends PluginMessageRecipient, Metadatable {
     void playSound(Location location, String sound, SoundCategory category, float volume, float pitch);
 
     /**
-     * Get existing rules
+     * Get an array containing the names of all the {@link GameRule}s.
      *
-     * @return An array of rules
+     * @return An array of {@link GameRule} names.
      */
     public String[] getGameRules();
 
@@ -1218,7 +1218,9 @@ public interface World extends PluginMessageRecipient, Metadatable {
      *
      * @param rule Rule to look up value of
      * @return String value of rule
+     * @deprecated use {@link #getGameRuleValue(GameRule)} instead
      */
+    @Deprecated
     public String getGameRuleValue(String rule);
 
     /**
@@ -1232,7 +1234,9 @@ public interface World extends PluginMessageRecipient, Metadatable {
      * @param rule Rule to set
      * @param value Value to set rule to
      * @return True if rule was set
+     * @deprecated use {@link #setGameRule(GameRule, Object)} instead.
      */
+    @Deprecated
     public boolean setGameRuleValue(String rule, String value);
 
     /**
@@ -1244,6 +1248,35 @@ public interface World extends PluginMessageRecipient, Metadatable {
     public boolean isGameRule(String rule);
 
     /**
+     * Get the current value for a given {@link GameRule}.
+     *
+     * @param rule the GameRule to check
+     * @param <T> the GameRule's type
+     * @return the current value
+     */
+    public <T> T getGameRuleValue(GameRule<T> rule);
+
+    /**
+     * Get the default value for a given {@link GameRule}. This value is not
+     * guaranteed to match the current value.
+     *
+     * @param rule the rule to return a default value for
+     * @param <T> the type of GameRule
+     * @return the default value
+     */
+    public <T> T getGameRuleDefault(GameRule<T> rule);
+
+    /**
+     * Set the given {@link GameRule}'s new value.
+     *
+     * @param rule the GameRule to update
+     * @param newValue the new value
+     * @param <T> the value type of the GameRule
+     * @return true if the value was successfully set
+     */
+    public <T> boolean setGameRule(GameRule<T> rule, T newValue);
+
+    /**
      * Gets the world border for this world.
      *
      * @return The world border for this world.