Add RegistrySupplier to ease registry delegation

common/src/main/java/me/shedaniel/architectury/registry/Registry.java

@@ -21,6 +21,7 @@ package me.shedaniel.architectury.registry;
 
 import net.minecraft.resources.ResourceKey;
 import net.minecraft.resources.ResourceLocation;
+import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import java.util.Map;
@@ -29,9 +30,21 @@ import java.util.Set;
 import java.util.function.Supplier;
 
 public interface Registry<T> extends Iterable<T> {
-    Supplier<T> delegate(ResourceLocation id);
+    @NotNull
+    default Supplier<T> delegate(ResourceLocation id) {
+        return delegateSupplied(id);
+    }
     
-    Supplier<T> register(ResourceLocation id, Supplier<T> supplier);
+    @NotNull
+    RegistrySupplier<T> delegateSupplied(ResourceLocation id);
+    
+    @NotNull
+    default Supplier<T> register(ResourceLocation id, Supplier<T> supplier) {
+        return registerSupplied(id, supplier);
+    }
+    
+    @NotNull
+    RegistrySupplier<T> registerSupplied(ResourceLocation id, Supplier<T> supplier);
     
     @Nullable
     ResourceLocation getId(T obj);

common/src/main/java/me/shedaniel/architectury/registry/RegistrySupplier.java

@@ -0,0 +1,83 @@
+/*
+ * This file is part of architectury.
+ * Copyright (C) 2020 shedaniel
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+package me.shedaniel.architectury.registry;
+
+import net.minecraft.resources.ResourceLocation;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Optional;
+import java.util.function.Consumer;
+import java.util.function.Supplier;
+import java.util.stream.Stream;
+
+public interface RegistrySupplier<T> extends Supplier<T> {
+    @NotNull
+    ResourceLocation getRegistryId();
+    
+    @NotNull
+    ResourceLocation getId();
+    
+    boolean isPresent();
+    
+    @Nullable
+    default T getOrNull() {
+        if (isPresent()) {
+            return get();
+        }
+        return null;
+    }
+    
+    @NotNull
+    default Optional<T> toOptional() {
+        return Optional.ofNullable(getOrNull());
+    }
+    
+    default void ifPresent(Consumer<? super T> action) {
+        if (isPresent()) {
+            action.accept(get());
+        }
+    }
+    
+    default void ifPresentOrElse(Consumer<? super T> action, Runnable emptyAction) {
+        if (isPresent()) {
+            action.accept(get());
+        } else {
+            emptyAction.run();
+        }
+    }
+    
+    @NotNull
+    default Stream<T> stream() {
+        if (!isPresent()) {
+            return Stream.empty();
+        } else {
+            return Stream.of(get());
+        }
+    }
+    
+    default T orElse(T other) {
+        return isPresent() ? get() : other;
+    }
+    
+    default T orElseGet(Supplier<? extends T> supplier) {
+        return isPresent() ? get() : supplier.get();
+    }
+}

fabric/src/main/java/me/shedaniel/architectury/registry/fabric/RegistriesImpl.java

@@ -19,15 +19,20 @@
 
 package me.shedaniel.architectury.registry.fabric;
 
+import com.google.common.base.Objects;
 import me.shedaniel.architectury.registry.Registries;
 import me.shedaniel.architectury.registry.Registry;
+import me.shedaniel.architectury.registry.RegistrySupplier;
 import net.minecraft.resources.ResourceKey;
 import net.minecraft.resources.ResourceLocation;
 import net.minecraft.util.LazyLoadedValue;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
-import java.util.*;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
 import java.util.function.Supplier;
 
 public class RegistriesImpl {
@@ -69,15 +74,53 @@ public class RegistriesImpl {
         }
         
         @Override
-        public Supplier<T> delegate(ResourceLocation id) {
+        public @NotNull RegistrySupplier<T> delegateSupplied(ResourceLocation id) {
             LazyLoadedValue<T> value = new LazyLoadedValue<>(() -> get(id));
-            return value::get;
+            return new RegistrySupplier<T>() {
+                @Override
+                public @NotNull ResourceLocation getRegistryId() {
+                    return delegate.key().location();
+                }
+                
+                @Override
+                public @NotNull ResourceLocation getId() {
+                    return id;
+                }
+                
+                @Override
+                public boolean isPresent() {
+                    return contains(id);
+                }
+                
+                @Override
+                public T get() {
+                    return value.get();
+                }
+                
+                @Override
+                public int hashCode() {
+                    return Objects.hashCode(getRegistryId(), getId());
+                }
+                
+                @Override
+                public boolean equals(Object obj) {
+                    if (this == obj) return true;
+                    if (!(obj instanceof RegistrySupplier)) return false;
+                    RegistrySupplier<?> other = (RegistrySupplier<?>) obj;
+                    return other.getRegistryId().equals(getRegistryId()) && other.getId().equals(getId());
+                }
+                
+                @Override
+                public String toString() {
+                    return getRegistryId().toString() + "@" + id.toString();
+                }
+            };
         }
         
         @Override
-        public Supplier<T> register(ResourceLocation id, Supplier<T> supplier) {
+        public @NotNull RegistrySupplier<T> registerSupplied(ResourceLocation id, Supplier<T> supplier) {
             net.minecraft.core.Registry.register(delegate, id, supplier.get());
-            return delegate(id);
+            return delegateSupplied(id);
         }
         
         @Override

forge/src/main/java/me/shedaniel/architectury/registry/forge/RegistriesImpl.java

@@ -19,11 +19,13 @@
 
 package me.shedaniel.architectury.registry.forge;
 
+import com.google.common.base.Objects;
 import com.google.common.collect.HashBasedTable;
 import com.google.common.collect.Table;
 import me.shedaniel.architectury.platform.forge.EventBuses;
 import me.shedaniel.architectury.registry.Registries;
 import me.shedaniel.architectury.registry.Registry;
+import me.shedaniel.architectury.registry.RegistrySupplier;
 import net.minecraft.resources.ResourceKey;
 import net.minecraft.resources.ResourceLocation;
 import net.minecraft.util.LazyLoadedValue;
@@ -34,6 +36,7 @@ import net.minecraftforge.fml.RegistryObject;
 import net.minecraftforge.registries.IForgeRegistry;
 import net.minecraftforge.registries.IForgeRegistryEntry;
 import net.minecraftforge.registries.RegistryManager;
+import org.jetbrains.annotations.NotNull;
 
 import javax.annotation.Nullable;
 import java.lang.reflect.Type;
@@ -106,15 +109,53 @@ public class RegistriesImpl {
         }
         
         @Override
-        public Supplier<T> delegate(ResourceLocation id) {
+        public @NotNull RegistrySupplier<T> delegateSupplied(ResourceLocation id) {
             LazyLoadedValue<T> value = new LazyLoadedValue<>(() -> get(id));
-            return value::get;
+            return new RegistrySupplier<T>() {
+                @Override
+                public @NotNull ResourceLocation getRegistryId() {
+                    return delegate.key().location();
+                }
+    
+                @Override
+                public @NotNull ResourceLocation getId() {
+                    return id;
+                }
+    
+                @Override
+                public boolean isPresent() {
+                    return contains(id);
+                }
+    
+                @Override
+                public T get() {
+                    return value.get();
+                }
+    
+                @Override
+                public int hashCode() {
+                    return Objects.hashCode(getRegistryId(), getId());
+                }
+    
+                @Override
+                public boolean equals(Object obj) {
+                    if (this == obj) return true;
+                    if (!(obj instanceof RegistrySupplier)) return false;
+                    RegistrySupplier<?> other = (RegistrySupplier<?>) obj;
+                    return other.getRegistryId().equals(getRegistryId()) && other.getId().equals(getId());
+                }
+    
+                @Override
+                public String toString() {
+                    return getRegistryId().toString() + "@" + id.toString();
+                }
+            };
         }
         
         @Override
-        public Supplier<T> register(ResourceLocation id, Supplier<T> supplier) {
+        public @NotNull RegistrySupplier<T> registerSupplied(ResourceLocation id, Supplier<T> supplier) {
             net.minecraft.core.Registry.register(delegate, id, supplier.get());
-            return delegate(id);
+            return delegateSupplied(id);
         }
         
         @Override
@@ -175,16 +216,92 @@ public class RegistriesImpl {
         }
         
         @Override
-        public Supplier<T> delegate(ResourceLocation id) {
+        public @NotNull RegistrySupplier<T> delegateSupplied(ResourceLocation id) {
             LazyLoadedValue<T> value = new LazyLoadedValue<>(() -> get(id));
-            return value::get;
+            return new RegistrySupplier<T>() {
+                @Override
+                public @NotNull ResourceLocation getRegistryId() {
+                    return delegate.getRegistryName();
+                }
+    
+                @Override
+                public @NotNull ResourceLocation getId() {
+                    return id;
+                }
+    
+                @Override
+                public boolean isPresent() {
+                    return contains(id);
+                }
+    
+                @Override
+                public T get() {
+                    return value.get();
+                }
+    
+                @Override
+                public int hashCode() {
+                    return Objects.hashCode(getRegistryId(), getId());
+                }
+    
+                @Override
+                public boolean equals(Object obj) {
+                    if (this == obj) return true;
+                    if (!(obj instanceof RegistrySupplier)) return false;
+                    RegistrySupplier<?> other = (RegistrySupplier<?>) obj;
+                    return other.getRegistryId().equals(getRegistryId()) && other.getId().equals(getId());
+                }
+    
+                @Override
+                public String toString() {
+                    return getRegistryId().toString() + "@" + id.toString();
+                }
+            };
         }
         
         @Override
-        public Supplier<T> register(ResourceLocation id, Supplier<T> supplier) {
+        public @NotNull RegistrySupplier<T> registerSupplied(ResourceLocation id, Supplier<T> supplier) {
             RegistryObject registryObject = RegistryObject.of(id, delegate);
             registry.put(delegate.getRegistrySuperType(), registryObject, () -> supplier.get().setRegistryName(id));
-            return registryObject;
+            return new RegistrySupplier<T>() {
+                @Override
+                public @NotNull ResourceLocation getRegistryId() {
+                    return delegate.getRegistryName();
+                }
+    
+                @Override
+                public @NotNull ResourceLocation getId() {
+                    return registryObject.getId();
+                }
+    
+                @Override
+                public boolean isPresent() {
+                    return registryObject.isPresent();
+                }
+    
+                @Override
+                public T get() {
+                    return (T) registryObject.get();
+                }
+    
+                @Override
+                public int hashCode() {
+                    return Objects.hashCode(getRegistryId(), getId());
+                }
+    
+                @Override
+                public boolean equals(Object obj) {
+                    if (this == obj) return true;
+                    if (!(obj instanceof RegistrySupplier)) return false;
+                    RegistrySupplier<?> other = (RegistrySupplier<?>) obj;
+                    return other.getRegistryId().equals(getRegistryId()) && other.getId().equals(getId());
+                }
+    
+                @Override
+                public String toString() {
+                    return getRegistryId().toString() + "@" + id.toString();
+                }
+            };
         }
         
         @Override