Add fixed codecs and implement toString in LibX codecs.

src/main/java/org/moddingx/libx/codec/MoreCodecs.java

@@ -1,6 +1,7 @@
 package org.moddingx.libx.codec;
 
 import com.google.gson.JsonElement;
+import com.google.gson.JsonPrimitive;
 import com.mojang.datafixers.util.Pair;
 import com.mojang.serialization.*;
 import net.minecraft.nbt.CompoundTag;
@@ -75,6 +76,33 @@ public static <T> Codec<T> error(String encodeMsg, String decodeMsg) {
     public static <T> Codec<Optional<T>> option(Codec<T> codec) {
         return new OptionCodec<>(codec);
     }
+
+    /**
+     * Creates a fixed codec that always encodes the {@link Unit#INSTANCE unit value} to the given serialized value.
+     * Decoding fille succeed if the serialized value equals the given value, otherwise it fails. Fixed codecs are
+     * useful in {@link Codec#either(Codec, Codec) either}-codecs.
+     */
+    public static Codec<Unit> fixed(Number value) {
+        return fixed(new Dynamic<>(JsonOps.INSTANCE, new JsonPrimitive(value)));
+    }
+
+    /**
+     * Creates a fixed codec that always encodes the {@link Unit#INSTANCE unit value} to the given serialized value.
+     * Decoding fille succeed if the serialized value equals the given value, otherwise it fails. Fixed codecs are
+     * useful in {@link Codec#either(Codec, Codec) either}-codecs.
+     */
+    public static Codec<Unit> fixed(String value) {
+        return fixed(new Dynamic<>(JsonOps.INSTANCE, new JsonPrimitive(value)));
+    }
+
+    /**
+     * Creates a fixed codec that always encodes the {@link Unit#INSTANCE unit value} to the given serialized value.
+     * Decoding fille succeed if the serialized value equals the given value, otherwise it fails. Fixed codecs are
+     * useful in {@link Codec#either(Codec, Codec) either}-codecs.
+     */
+    public static Codec<Unit> fixed(Dynamic<?> value) {
+        return new FixedCodec<>(value);
+    }
 
     /**
      * Gets a codec that encodes an {@link Enum enum} as a string.

src/main/java/org/moddingx/libx/impl/codec/EnumCodec.java

@@ -69,4 +69,9 @@ private <T> DataResult<Pair<A, T>> decodeByName(DynamicOps<T> ops, T input) {
                     .flatMap(str -> CodecHelper.doesNotThrow(() -> Enum.valueOf(this.clazz, str)))
                     .map(r -> Pair.of(r, ops.empty()));
     }
+
+    @Override
+    public String toString() {
+        return "EnumCodec[" + this.clazz.getName() + "]";
+    }
 }

src/main/java/org/moddingx/libx/impl/codec/ErrorCodec.java

@@ -24,4 +24,9 @@ public <T> DataResult<T> encode(A input, DynamicOps<T> ops, T prefix) {
     public <T> DataResult<Pair<A, T>> decode(DynamicOps<T> ops, T input) {
         return DataResult.error(() -> this.decodeMsg);
     }
+
+    @Override
+    public String toString() {
+        return "ErrorCodec[enc=" + this.encodeMsg + ", dec=" + this.decodeMsg + "]";
+    }
 }

src/main/java/org/moddingx/libx/impl/codec/FixedCodec.java

@@ -0,0 +1,40 @@
+package org.moddingx.libx.impl.codec;
+
+import com.mojang.datafixers.util.Pair;
+import com.mojang.serialization.Codec;
+import com.mojang.serialization.DataResult;
+import com.mojang.serialization.Dynamic;
+import com.mojang.serialization.DynamicOps;
+import net.minecraft.util.Unit;
+
+import java.util.Objects;
+
+public class FixedCodec<A> implements Codec<Unit> {
+
+    private final Dynamic<A> serializedValue;
+
+    public FixedCodec(Dynamic<A> serializedValue) {
+        this.serializedValue = serializedValue;
+    }
+
+
+    @Override
+    public <T> DataResult<T> encode(Unit unit, DynamicOps<T> ops, T prefix) {
+        return ops.mergeToPrimitive(prefix, this.serializedValue.convert(ops).getValue());
+    }
+
+    @Override
+    public <T> DataResult<Pair<Unit, T>> decode(DynamicOps<T> ops, T input) {
+        Dynamic<A> dynamic = new Dynamic<>(ops, input).convert(this.serializedValue.getOps());
+        if (Objects.equals(this.serializedValue, dynamic)) {
+            return DataResult.success(Pair.of(Unit.INSTANCE, ops.empty()));
+        } else {
+            return DataResult.error(() -> "Wrong value in fixed codec.");
+        }
+    }
+
+    @Override
+    public String toString() {
+        return "FixedCodec[" + this.serializedValue + "]";
+    }
+}

src/main/java/org/moddingx/libx/impl/codec/LazyCodec.java

@@ -25,4 +25,9 @@ public <T> DataResult<T> encode(A input, DynamicOps<T> ops, T prefix) {
     public <T> DataResult<Pair<A, T>> decode(DynamicOps<T> ops, T input) {
         return this.codec.get().decode(ops, input);
     }
+
+    @Override
+    public String toString() {
+        return "LazyCodec[...]";
+    }
 }

src/main/java/org/moddingx/libx/impl/codec/MapDispatchedCodec.java

@@ -68,4 +68,9 @@ public <T> DataResult<Pair<A, T>> decode(DynamicOps<T> ops, T input) {
                         )
                 );
     }
+
+    @Override
+    public String toString() {
+        return "MapDispatchedCodec[key=" + this.keyCodec + "]";
+    }
 }

src/main/java/org/moddingx/libx/impl/codec/OptionCodec.java

@@ -4,6 +4,7 @@
 import com.mojang.serialization.Codec;
 import com.mojang.serialization.DataResult;
 import com.mojang.serialization.DynamicOps;
+import com.mojang.serialization.Lifecycle;
 
 import java.util.Objects;
 import java.util.Optional;
@@ -47,4 +48,9 @@ public <T> DataResult<Pair<Optional<A>, T>> decode(DynamicOps<T> ops, T input) {
             }
         });
     }
+
+    @Override
+    public String toString() {
+        return "OptionCodec[" + this.codec + "]";
+    }
 }

src/main/java/org/moddingx/libx/impl/codec/TrueOptionalMapCodec.java

@@ -38,4 +38,9 @@ public <T> RecordBuilder<T> encode(final Optional<A> input, final DynamicOps<T>
             return prefix;
         }
     }
+
+    @Override
+    public String toString() {
+        return "TrueOptionalMapCodec[" + this.name + ": " + this.codec + "]";
+    }
 }

src/main/java/org/moddingx/libx/impl/codec/TypeMappedCodec.java

@@ -8,6 +8,7 @@
 
 import javax.annotation.Nullable;
 import java.util.List;
+import java.util.stream.Collectors;
 
 public class TypeMappedCodec<A> implements Codec<A> {
 
@@ -50,4 +51,9 @@ public <T> DataResult<Pair<A, T>> decode(DynamicOps<T> ops, T input) {
             return this.fallback.decode(ops, input);
         }
     }
+
+    @Override
+    public String toString() {
+        return "TypeMappedCodec[known=" + this.encoders.stream().map(TypedEncoder::resultClass).map(Class::getName).collect(Collectors.joining(", ", "(", ")")) + ", fallback=" + this.fallback + "]";
+    }
 }