Small refactor

api/src/main/java/com/viaversion/viaversion/api/minecraft/Holder.java

@@ -22,9 +22,9 @@
  */
 package com.viaversion.viaversion.api.minecraft;
 
-import com.viaversion.viaversion.util.Either;
+import com.google.common.base.Preconditions;
 
-public final class Holder<T> implements Either<Integer, T> {
+public final class Holder<T> {
 
     private final T value;
     private final int id;
@@ -39,27 +39,28 @@ public final class Holder<T> implements Either<Integer, T> {
         this.id = -1;
     }
 
+    /**
+     * Returns true if this holder is backed by a direct value.
+     *
+     * @return true if the holder is direct
+     * @see #hasId()
+     */
     public boolean isDirect() {
+        return id == -1;
+    }
+
+    /**
+     * Returns true if this holder has an id.
+     *
+     * @return true if this holder has an id
+     * @see #isDirect()
+     */
+    public boolean hasId() {
         return id != -1;
     }
 
-    @Override
-    public boolean isLeft() {
-        return value != null;
-    }
-
-    @Override
-    public boolean isRight() {
-        return value == null;
-    }
-
-    @Override
-    public Integer left() {
-        return id;
-    }
-
-    @Override
-    public T right() {
+    public T value() {
+        Preconditions.checkArgument(isDirect(), "Holder is not direct");
         return value;
     }
 

api/src/main/java/com/viaversion/viaversion/api/minecraft/SoundEvent.java

@@ -26,19 +26,23 @@ import org.checkerframework.checker.nullness.qual.Nullable;
 
 public final class SoundEvent {
 
-    private final String resourceLocation;
+    private final String identifier;
     private final Float fixedRange;
 
-    public SoundEvent(final String resourceLocation, @Nullable final Float fixedRange) {
-        this.resourceLocation = resourceLocation;
+    public SoundEvent(final String identifier, @Nullable final Float fixedRange) {
+        this.identifier = identifier;
         this.fixedRange = fixedRange;
     }
 
-    public String resourceLocation() {
-        return resourceLocation;
+    public String identifier() {
+        return identifier;
     }
 
     public @Nullable Float fixedRange() {
         return fixedRange;
     }
+
+    public SoundEvent withIdentifier(final String identifier) {
+        return new SoundEvent(identifier, this.fixedRange);
+    }
 }

api/src/main/java/com/viaversion/viaversion/api/type/types/misc/HolderType.java

@@ -43,11 +43,11 @@ public abstract class HolderType<T> extends Type<Holder<T>> {
 
     @Override
     public void write(final ByteBuf buffer, final Holder<T> object) throws Exception {
-        if (object.isLeft()) {
+        if (object.hasId()) {
             Type.VAR_INT.writePrimitive(buffer, object.id() + 1); // Normalize id
         } else {
             Type.VAR_INT.writePrimitive(buffer, 0);
-            writeDirect(buffer, object.right());
+            writeDirect(buffer, object.value());
         }
     }
 

api/src/main/java/com/viaversion/viaversion/api/type/types/misc/SoundEventType.java

@@ -37,7 +37,7 @@ public final class SoundEventType extends HolderType<SoundEvent> {
 
     @Override
     public void writeDirect(final ByteBuf buffer, final SoundEvent value) throws Exception {
-        Type.STRING.write(buffer, value.resourceLocation());
+        Type.STRING.write(buffer, value.identifier());
         Type.OPTIONAL_FLOAT.write(buffer, value.fixedRange());
     }
 }