Item functions

src/main/java/net/glowstone/block/ItemTable.java

@@ -101,6 +101,10 @@
 import net.glowstone.block.blocktype.BlockWeb;
 import net.glowstone.block.blocktype.BlockWoodenTrapDoor;
 import net.glowstone.block.blocktype.BlockWorkbench;
+import net.glowstone.block.function.GlowBlockFunctionHandler;
+import net.glowstone.block.function.GlowItemFunctionHandler;
+import net.glowstone.block.function.ItemFunction;
+import net.glowstone.block.function.ItemFunctionHandler;
 import net.glowstone.block.itemtype.ItemArmorStand;
 import net.glowstone.block.itemtype.ItemBanner;
 import net.glowstone.block.itemtype.ItemBoat;
@@ -154,11 +158,14 @@ public final class ItemTable {
     private static final ItemTable INSTANCE = new ItemTable();
 
     static {
-        INSTANCE.registerBuiltins();
+        INSTANCE.init();
     }
 
     private final EnumMap<Material, ItemType> materialToType = new EnumMap<>(Material.class);
     private final Map<NamespacedKey, ItemType> extraTypes = new HashMap<>();
+    private final Map<String, ItemFunctionHandler> itemFunctionHandlers = new HashMap<>();
+    private final ItemFunctionHandler itemFunctionHandler = new GlowItemFunctionHandler();
+    private final ItemFunctionHandler blockFunctionHandler = new GlowBlockFunctionHandler();
     private int nextBlockId;
     private int nextItemId;
 
@@ -168,6 +175,15 @@ public final class ItemTable {
     private ItemTable() {
     }
 
+    private void init() {
+        registerBuiltins();
+        assignHandler("block.place.allow", blockFunctionHandler);
+        assignHandler("block.interact", blockFunctionHandler);
+        assignHandler("block.pulse", blockFunctionHandler);
+        assignHandler("block.pulse.rate", blockFunctionHandler);
+        assignHandler("block.pulse.multiple", blockFunctionHandler);
+    }
+
     public static ItemTable instance() {
         return INSTANCE;
     }
@@ -627,4 +643,34 @@ public BlockType getBlock(Material mat) {
         return null;
     }
 
+    ////////////////////////////////////////////////////////////////////////////
+    // Functions
+
+    /**
+     * Assigns a function handler to accept new function registrations of this type.
+     * @param functionality The type of function this function handler accepts
+     * @param handler The handler
+     * @return The resultant handler that will be used to handle functions of this type
+     */
+    public ItemFunctionHandler assignHandler(String functionality, ItemFunctionHandler handler) {
+        return itemFunctionHandlers.putIfAbsent(functionality, handler);
+    }
+
+    /**
+     * Get the function handler that accepts functions of this type.
+     * @param functionality The function type
+     * @return The function handler
+     */
+    public ItemFunctionHandler getFunctionHandler(String functionality) {
+        return itemFunctionHandlers.get(functionality);
+    }
+
+    /**
+     * Add this function to the specified item's behavior
+     * @param item The item
+     * @param function The function to add
+     */
+    public void addFunction(ItemType item, ItemFunction function) {
+        itemFunctionHandlers.get(function.getFunctionality()).accept(item, function);
+    }
 }

src/main/java/net/glowstone/block/blocktype/BlockAnvil.java

@@ -1,26 +1,18 @@
 package net.glowstone.block.blocktype;
 
-import java.util.Arrays;
-import java.util.Collection;
 import net.glowstone.block.GlowBlock;
-import net.glowstone.entity.GlowPlayer;
-import net.glowstone.inventory.GlowAnvilInventory;
 import net.glowstone.inventory.ToolType;
 import org.bukkit.Material;
-import org.bukkit.block.BlockFace;
 import org.bukkit.inventory.ItemStack;
-import org.bukkit.util.Vector;
+
+import java.util.Arrays;
+import java.util.Collection;
 
 public class BlockAnvil extends BlockFalling {
 
     public BlockAnvil() {
         super(Material.ANVIL);
-    }
-
-    @Override
-    public boolean blockInteract(GlowPlayer player, GlowBlock block, BlockFace face,
-        Vector clickedLoc) {
-        return player.openInventory(new GlowAnvilInventory(player)) != null;
+        addFunction(Functions.Interact.ANVIL);
     }
 
     @Override

src/main/java/net/glowstone/block/blocktype/BlockCactus.java

@@ -6,6 +6,7 @@
 import net.glowstone.EventFactory;
 import net.glowstone.block.GlowBlock;
 import net.glowstone.block.GlowBlockState;
+import net.glowstone.block.function.BlockFunctions;
 import org.bukkit.Material;
 import org.bukkit.block.Block;
 import org.bukkit.block.BlockFace;
@@ -14,10 +15,9 @@
 
 public class BlockCactus extends BlockType {
 
-    @Override
-    public boolean canPlaceAt(GlowBlock block, BlockFace against) {
-        Material below = block.getRelative(BlockFace.DOWN).getType();
-        return (below == Material.CACTUS || below == Material.SAND) && !hasNearBlocks(block);
+    public BlockCactus() {
+        super();
+        addFunction(Functions.PlaceAllow.CACTUS);
     }
 
     @Override
@@ -75,16 +75,7 @@ public void updateBlock(GlowBlock block) {
         }
     }
 
-    private boolean hasNearBlocks(GlowBlock block) {
-        for (BlockFace face : SIDES) {
-            if (!canPlaceNear(block.getRelative(face).getType())) {
-                return true;
-            }
-        }
-        return false;
-    }
-
-    private boolean canPlaceNear(Material type) {
+    private static boolean canPlaceNear(Material type) {
         // TODO: return true for non-buildable blocks
         switch (type) {
             case GRASS:
@@ -133,4 +124,30 @@ public Collection<ItemStack> getDrops(GlowBlock me, ItemStack tool) {
         // Overridden for cactus to remove data from the dropped item
         return Collections.unmodifiableList(Arrays.asList(new ItemStack(Material.CACTUS)));
     }
+
+    /**
+     * Builtin block functions specific to cactus.
+     */
+    public static class Functions {
+
+        public static class PlaceAllow {
+
+            /**
+             * Check for allowing place for cactus.
+             */
+            public static final BlockFunctions.BlockFunctionPlaceAllow CACTUS = (block,
+                against) -> {
+                Material below = block.getRelative(BlockFace.DOWN).getType();
+                boolean hasSurroundingBlocks = false;
+                for (BlockFace face : SIDES) {
+                    if (!canPlaceNear(block.getRelative(face).getType())) {
+                        hasSurroundingBlocks = true;
+                        break;
+                    }
+                }
+                return ((below == Material.CACTUS) || below == Material.SAND)
+                    && !hasSurroundingBlocks;
+            };
+        }
+    }
 }

src/main/java/net/glowstone/block/blocktype/BlockChest.java

@@ -1,7 +1,5 @@
 package net.glowstone.block.blocktype;
 
-import java.util.ArrayList;
-import java.util.Collection;
 import net.glowstone.GlowServer;
 import net.glowstone.block.GlowBlock;
 import net.glowstone.block.GlowBlockState;
@@ -10,14 +8,16 @@
 import net.glowstone.chunk.GlowChunk;
 import net.glowstone.entity.GlowPlayer;
 import org.bukkit.Material;
-import org.bukkit.Statistic;
 import org.bukkit.block.BlockFace;
 import org.bukkit.block.BlockState;
 import org.bukkit.inventory.ItemStack;
 import org.bukkit.material.Chest;
 import org.bukkit.material.MaterialData;
 import org.bukkit.util.Vector;
 
+import java.util.ArrayList;
+import java.util.Collection;
+
 public class BlockChest extends BlockContainer {
 
     private final boolean isTrapped;
@@ -26,8 +26,15 @@ public BlockChest() {
         this(false);
     }
 
+    /**
+     * Creates a block type for chest functionality with optional trapped behavior.
+     *
+     * @param isTrapped If the chest uses the trapped behavior
+     */
     public BlockChest(boolean isTrapped) {
+        super();
         this.isTrapped = isTrapped;
+        addFunction(Functions.Interact.CHEST);
     }
 
     private static BlockFace getFacingDirection(BlockFace myFacing, BlockFace otherFacing,
@@ -115,23 +122,6 @@ public void placeBlock(GlowPlayer player, GlowBlockState state, BlockFace face,
         }
     }
 
-    @Override
-    public boolean blockInteract(GlowPlayer player, GlowBlock block, BlockFace face,
-        Vector clickedLoc) {
-        BlockState state = block.getState();
-        if (state instanceof org.bukkit.block.Chest) {
-            org.bukkit.block.Chest chest = (org.bukkit.block.Chest) state;
-            player.openInventory(chest.getInventory());
-            player.incrementStatistic(Statistic.CHEST_OPENED);
-            return true;
-        }
-
-        GlowServer.logger
-            .warning("Calling blockInteract on BlockChest, but BlockState is " + state);
-
-        return false;
-    }
-
     @Override
     public boolean canPlaceAt(GlowBlock block, BlockFace against) {
         Collection<BlockFace> nearChests = searchChests(block);

src/main/java/net/glowstone/block/blocktype/BlockDoublePlant.java

@@ -48,29 +48,6 @@ public Collection<ItemStack> getDrops(GlowBlock block, ItemStack tool) {
         return BlockDropless.EMPTY_STACK;
     }
 
-    @Override
-    public void blockDestroy(GlowPlayer player, GlowBlock block, BlockFace face) {
-        MaterialData data = block.getState().getData();
-        if (data instanceof DoublePlant) {
-            DoublePlantSpecies species = ((DoublePlant) data).getSpecies();
-            if (species == DoublePlantSpecies.PLANT_APEX) {
-                GlowBlock blockUnder = block.getRelative(BlockFace.DOWN);
-                if (!(blockUnder.getState().getData() instanceof DoublePlant)) {
-                    return;
-                }
-                blockUnder.setType(Material.AIR);
-            } else {
-                GlowBlock blockTop = block.getRelative(BlockFace.UP);
-                if (!(blockTop.getState().getData() instanceof DoublePlant)) {
-                    return;
-                }
-                blockTop.setType(Material.AIR);
-            }
-        } else {
-            warnMaterialData(DoublePlant.class, data);
-        }
-    }
-
     @Override
     public boolean isFertilizable(GlowBlock block) {
         MaterialData data = block.getState().getData();

src/main/java/net/glowstone/block/blocktype/BlockJukebox.java

@@ -1,54 +1,29 @@
 package net.glowstone.block.blocktype;
 
-import java.util.Arrays;
-import java.util.Collection;
 import net.glowstone.block.GlowBlock;
 import net.glowstone.block.entity.BlockEntity;
 import net.glowstone.block.entity.JukeboxEntity;
 import net.glowstone.block.entity.state.GlowJukebox;
 import net.glowstone.chunk.GlowChunk;
-import net.glowstone.entity.GlowPlayer;
-import org.bukkit.GameMode;
-import org.bukkit.block.BlockFace;
-import org.bukkit.block.Jukebox;
 import org.bukkit.inventory.ItemStack;
-import org.bukkit.util.Vector;
 
-public class BlockJukebox extends BlockType {
+import java.util.Arrays;
+import java.util.Collection;
 
-    @Override
-    public BlockEntity createBlockEntity(GlowChunk chunk, int cx, int cy, int cz) {
-        return new JukeboxEntity(chunk.getBlock(cx, cy, cz));
-    }
+public class BlockJukebox extends BlockType {
 
-    @Override
-    public boolean blockInteract(GlowPlayer player, GlowBlock block, BlockFace face,
-        Vector clickedLoc) {
-        Jukebox jukebox = (Jukebox) block.getState();
-        if (jukebox.isPlaying()) {
-            jukebox.eject();
-            jukebox.update();
-            return true;
-        }
-        ItemStack handItem = player.getItemInHand();
-        if (handItem != null && handItem.getType().isRecord()) {
-            jukebox.setPlaying(handItem.getType());
-            jukebox.update();
-            if (player.getGameMode() != GameMode.CREATIVE) {
-                handItem.setAmount(handItem.getAmount() - 1);
-                player.setItemInHand(handItem);
-            }
-            return true;
-        }
-        return false;
+    /**
+     * Creates a block type with jukebox functionality.
+     */
+    public BlockJukebox() {
+        super();
+        addFunction(Functions.Interact.JUKEBOX);
+        addFunction(Functions.Destroy.JUKEBOX);
     }
 
     @Override
-    public void blockDestroy(GlowPlayer player, GlowBlock block, BlockFace face) {
-        Jukebox jukebox = (Jukebox) block.getState();
-        if (jukebox.eject()) {
-            jukebox.update();
-        }
+    public BlockEntity createBlockEntity(GlowChunk chunk, int cx, int cy, int cz) {
+        return new JukeboxEntity(chunk.getBlock(cx, cy, cz));
     }
 
     @Override