Add block/meta and item/meta pair classes (#98)

src/main/java/com/gtnewhorizon/gtnhlib/util/data/BlockMeta.java

@@ -0,0 +1,83 @@
+package com.gtnewhorizon.gtnhlib.util.data;
+
+import java.util.Objects;
+
+import javax.annotation.Nonnull;
+
+import net.minecraft.block.Block;
+
+/**
+ * A mutable implementation of {@link ImmutableBlockMeta}. If your API should return a mutable pair, return this
+ * instead. Must follow the same contracts as the immutable version if this is ever upcast to a
+ * {@link ImmutableBlockMeta} in your API. If this type is exposed instead of the immutable interface, assume that the
+ * contained values can change.
+ */
+public class BlockMeta implements ImmutableBlockMeta {
+
+    @Nonnull
+    private Block block;
+    private int meta;
+
+    public BlockMeta(@Nonnull Block block, int meta) {
+        this.block = block;
+        this.meta = meta;
+    }
+
+    public BlockMeta(@Nonnull Block block) {
+        this(block, 0);
+    }
+
+    @Override
+    @Nonnull
+    public Block getBlock() {
+        return block;
+    }
+
+    @Override
+    public int getBlockMeta() {
+        return meta;
+    }
+
+    /**
+     * Note: see the header comment in {@link ImmutableBlockMeta} for this method's contract.
+     */
+    public BlockMeta setBlock(@Nonnull Block block) {
+        this.block = Objects.requireNonNull(block);
+
+        return this;
+    }
+
+    /**
+     * Note: see the header comment in {@link ImmutableBlockMeta} for this method's contract.
+     */
+    public BlockMeta setBlockMeta(int meta) {
+        this.meta = meta;
+
+        return this;
+    }
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + block.hashCode();
+        result = prime * result + meta;
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null) return false;
+        if (getClass() != obj.getClass()) return false;
+        BlockMeta other = (BlockMeta) obj;
+        if (!block.equals(other.block)) return false;
+        if (meta != other.meta) return false;
+        return true;
+    }
+
+    @Override
+    public String toString() {
+        return "BlockMeta [block=" + block + ", meta=" + meta + "]";
+    }
+}

src/main/java/com/gtnewhorizon/gtnhlib/util/data/BlockSupplier.java

@@ -0,0 +1,15 @@
+package com.gtnewhorizon.gtnhlib.util.data;
+
+import java.util.function.Supplier;
+
+import net.minecraft.block.Block;
+
+/**
+ * A supplier that provides an Block. This is its own type because superclasses save their generics, allowing the JVM to
+ * differentiate between functional interfaces at runtime. Without this interface, two methods overloads that accept a
+ * Supplier with different generics but an otherwise identical method signature would cause a compilation error.
+ */
+@FunctionalInterface
+public interface BlockSupplier extends Supplier<Block> {
+
+}

src/main/java/com/gtnewhorizon/gtnhlib/util/data/IMod.java

@@ -0,0 +1,15 @@
+package com.gtnewhorizon.gtnhlib.util.data;
+
+/**
+ * An interface for any mod enums. Represents a mod.
+ */
+public interface IMod {
+
+    boolean isModLoaded();
+
+    /** Gets the mod id. */
+    String getID();
+
+    /** Gets the mod's resource location prefix. */
+    String getResourceLocation();
+}

src/main/java/com/gtnewhorizon/gtnhlib/util/data/ImmutableBlockMeta.java

@@ -0,0 +1,51 @@
+package com.gtnewhorizon.gtnhlib.util.data;
+
+import javax.annotation.Nonnull;
+
+import net.minecraft.block.Block;
+import net.minecraft.item.Item;
+import net.minecraftforge.oredict.OreDictionary;
+
+/**
+ * An immutable block-meta pair. This must not be cast down to its mutable version unless you have a very good reason.
+ * It can be assumed that the values of {@link #getBlock()} and {@link #getBlockMeta()} will never change for this
+ * object if the object is exposed through an API.
+ */
+public interface ImmutableBlockMeta {
+
+    /**
+     * The value of this must not change while this object is exposed via an API.
+     * 
+     * @return The block stored in this pair.
+     */
+    @Nonnull
+    public Block getBlock();
+
+    /**
+     * The value of this must not change while this object is exposed via an API.
+     * 
+     * @return The block's metadata stored in this pair. May be {@link OreDictionary#WILDCARD_VALUE}.
+     */
+    public int getBlockMeta();
+
+    /**
+     * Gets the corresponding item for this block. Subclasses may provide a faster implementation.
+     */
+    public default Item getItem() {
+        return Item.getItemFromBlock(getBlock());
+    }
+
+    /**
+     * Checks if this pair matches the given block & meta.
+     * 
+     * @param block The block.
+     * @param meta  The meta. If this parameter or {@link #getBlockMeta()} equals {@link OreDictionary#WILDCARD_VALUE}
+     *              then meta checks are ignored.
+     * @return Whether this pair matches or not.
+     */
+    public default boolean matches(Block block, int meta) {
+        return getBlock() == block
+                && (meta == OreDictionary.WILDCARD_VALUE || getBlockMeta() == OreDictionary.WILDCARD_VALUE
+                        || getBlockMeta() == meta);
+    }
+}

src/main/java/com/gtnewhorizon/gtnhlib/util/data/ImmutableItemMeta.java

@@ -0,0 +1,69 @@
+package com.gtnewhorizon.gtnhlib.util.data;
+
+import javax.annotation.Nonnull;
+
+import net.minecraft.block.Block;
+import net.minecraft.init.Items;
+import net.minecraft.item.Item;
+import net.minecraft.item.ItemStack;
+import net.minecraftforge.oredict.OreDictionary;
+
+/**
+ * An immutable item-meta pair. This must not be cast down to its mutable version unless you have a very good reason. It
+ * can be assumed that the values of {@link #getItem()} and {@link #getItemMeta()} will never change for this object if
+ * the object is exposed through an API.
+ */
+public interface ImmutableItemMeta {
+
+    /**
+     * The value of this must not change while this object is exposed via an API.
+     * 
+     * @return The item stored in this pair.
+     */
+    @Nonnull
+    public Item getItem();
+
+    /**
+     * The value of this must not change while this object is exposed via an API.
+     * 
+     * @return The item's metadata stored in this pair. May be {@link OreDictionary#WILDCARD_VALUE}.
+     */
+    public int getItemMeta();
+
+    /**
+     * Gets the corresponding block for this item. Subclasses may provide a faster implementation.
+     */
+    public default Block getBlock() {
+        return Block.getBlockFromItem(getItem());
+    }
+
+    /**
+     * Checks if this pair matches the given ItemStack's item and metadata.
+     */
+    public default boolean matches(ItemStack stack) {
+        if (stack == null) return false;
+
+        return matches(stack.getItem(), Items.feather.getDamage(stack));
+    }
+
+    /**
+     * Checks if this pair matches the given item & meta.
+     * 
+     * @param Item The item.
+     * @param meta The meta. If this parameter or {@link #getItemMeta()} equals {@link OreDictionary#WILDCARD_VALUE}
+     *             then meta checks are ignored.
+     * @return Whether this pair matches or not.
+     */
+    public default boolean matches(Item item, int meta) {
+        return getItem() == item
+                && (meta == OreDictionary.WILDCARD_VALUE || getItemMeta() == OreDictionary.WILDCARD_VALUE
+                        || getItemMeta() == meta);
+    }
+
+    /** Converts this pair to an ItemStack. */
+    public default ItemStack toStack(int amount) {
+        int meta = getItemMeta();
+
+        return new ItemStack(getItem(), amount, meta == OreDictionary.WILDCARD_VALUE ? 0 : meta);
+    }
+}

src/main/java/com/gtnewhorizon/gtnhlib/util/data/ItemMeta.java

@@ -0,0 +1,82 @@
+package com.gtnewhorizon.gtnhlib.util.data;
+
+import java.util.Objects;
+
+import javax.annotation.Nonnull;
+
+import net.minecraft.item.Item;
+
+/**
+ * A mutable implementation of {@link ImmutableItemMeta}. If your API should return a mutable pair, return this instead.
+ * Must follow the same contracts as the immutable version if this is ever upcast to a {@link ImmutableItemMeta} in your
+ * API. If this type is exposed instead of the immutable interface, assume that the contained values can change.
+ */
+public class ItemMeta implements ImmutableItemMeta {
+
+    @Nonnull
+    private Item item;
+    private int meta;
+
+    public ItemMeta(@Nonnull Item item, int meta) {
+        this.item = item;
+        this.meta = meta;
+    }
+
+    public ItemMeta(@Nonnull Item item) {
+        this(item, 0);
+    }
+
+    @Override
+    @Nonnull
+    public Item getItem() {
+        return item;
+    }
+
+    @Override
+    public int getItemMeta() {
+        return meta;
+    }
+
+    /**
+     * Note: see the header comment in {@link ImmutableItemMeta} for this method's contract.
+     */
+    public ItemMeta setItem(@Nonnull Item item) {
+        this.item = Objects.requireNonNull(item);
+
+        return this;
+    }
+
+    /**
+     * Note: see the header comment in {@link ImmutableItemMeta} for this method's contract.
+     */
+    public ItemMeta setItemMeta(int meta) {
+        this.meta = meta;
+
+        return this;
+    }
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + item.hashCode();
+        result = prime * result + meta;
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null) return false;
+        if (getClass() != obj.getClass()) return false;
+        ItemMeta other = (ItemMeta) obj;
+        if (!item.equals(other.item)) return false;
+        if (meta != other.meta) return false;
+        return true;
+    }
+
+    @Override
+    public String toString() {
+        return "ItemMeta [item=" + item + ", meta=" + meta + "]";
+    }
+}

src/main/java/com/gtnewhorizon/gtnhlib/util/data/ItemStackSupplier.java

@@ -0,0 +1,16 @@
+package com.gtnewhorizon.gtnhlib.util.data;
+
+import java.util.function.Supplier;
+
+import net.minecraft.item.ItemStack;
+
+/**
+ * A supplier that provides an ItemStack. This is its own type because superclasses save their generics, allowing the
+ * JVM to differentiate between functional interfaces at runtime. Without this interface, two methods overloads that
+ * accept a Supplier with different generics but an otherwise identical method signature would cause a compilation
+ * error.
+ */
+@FunctionalInterface
+public interface ItemStackSupplier extends Supplier<ItemStack> {
+
+}

src/main/java/com/gtnewhorizon/gtnhlib/util/data/ItemSupplier.java

@@ -0,0 +1,15 @@
+package com.gtnewhorizon.gtnhlib.util.data;
+
+import java.util.function.Supplier;
+
+import net.minecraft.item.Item;
+
+/**
+ * A supplier that provides an Item. This is its own type because superclasses save their generics, allowing the JVM to
+ * differentiate between functional interfaces at runtime. Without this interface, two methods overloads that accept a
+ * Supplier with different generics but an otherwise identical method signature would cause a compilation error.
+ */
+@FunctionalInterface
+public interface ItemSupplier extends Supplier<Item> {
+
+}