Make defaultValue a supplier and fix some checkstyle in ConfigNode

src/main/java/org/mvplugins/multiverse/core/configuration/node/ConfigNode.java

@@ -2,6 +2,7 @@ package org.mvplugins.multiverse.core.configuration.node;
 
 import java.util.function.BiConsumer;
 import java.util.function.Function;
+import java.util.function.Supplier;
 
 import io.vavr.control.Option;
 import io.vavr.control.Try;
@@ -10,6 +11,7 @@ import org.jetbrains.annotations.Nullable;
 
 /**
  * A node that contains a value.
+ *
  * @param <T>   The type of the value.
  */
 public class ConfigNode<T> extends ConfigHeaderNode implements ValueNode<T> {
@@ -19,19 +21,18 @@ public class ConfigNode<T> extends ConfigHeaderNode implements ValueNode<T> {
      *
      * @param path  The path of the node.
      * @param type  The type of the value.
-     * @return The new builder.
      * @param <T>   The type of the value.
+     * @return The new builder.
      */
     public static @NotNull <T> ConfigNode.Builder<T, ? extends ConfigNode.Builder<T, ?>> builder(
             @NotNull String path,
-            @NotNull Class<T> type
-    ) {
+            @NotNull Class<T> type) {
         return new ConfigNode.Builder<>(path, type);
     }
 
     protected final @Nullable String name;
     protected final @NotNull Class<T> type;
-    protected final @Nullable T defaultValue;
+    protected final @Nullable Supplier<T> defaultValue;
     protected final @Nullable NodeSerializer<T> serializer;
     protected final @Nullable Function<T, Try<Void>> validator;
     protected final @Nullable BiConsumer<T, T> onSetValue;
@@ -41,11 +42,10 @@ public class ConfigNode<T> extends ConfigHeaderNode implements ValueNode<T> {
             @NotNull String[] comments,
             @Nullable String name,
             @NotNull Class<T> type,
-            @Nullable T defaultValue,
+            @Nullable Supplier<T> defaultValue,
             @Nullable NodeSerializer<T> serializer,
             @Nullable Function<T, Try<Void>> validator,
-            @Nullable BiConsumer<T, T> onSetValue
-    ) {
+            @Nullable BiConsumer<T, T> onSetValue) {
         super(path, comments);
         this.name = name;
         this.type = type;
@@ -76,7 +76,10 @@ public class ConfigNode<T> extends ConfigHeaderNode implements ValueNode<T> {
      */
     @Override
     public @Nullable T getDefaultValue() {
-        return defaultValue;
+        if (defaultValue != null) {
+            return defaultValue.get();
+        }
+        return null;
     }
 
     public @Nullable NodeSerializer<T> getSerializer() {
@@ -115,7 +118,7 @@ public class ConfigNode<T> extends ConfigHeaderNode implements ValueNode<T> {
 
         protected @Nullable String name;
         protected @NotNull final Class<T> type;
-        protected @Nullable T defaultValue;
+        protected @Nullable Supplier<T> defaultValue;
         protected @Nullable NodeSerializer<T> serializer;
         protected @Nullable Function<T, Try<Void>> validator;
         protected @Nullable BiConsumer<T, T> onSetValue;
@@ -142,8 +145,19 @@ public class ConfigNode<T> extends ConfigHeaderNode implements ValueNode<T> {
          * @return This builder.
          */
         public @NotNull B defaultValue(@NotNull T defaultValue) {
+            this.defaultValue = () -> defaultValue;
+            return self();
+        }
+
+        /**
+         * Sets the default value for this node.
+         *
+         * @param defaultValue The default value supplier.
+         * @return This builder.
+         */
+        public @NotNull B defaultValue(@NotNull Supplier<T> defaultValue) {
             this.defaultValue = defaultValue;
-            return (B) this;
+            return self();
         }
 
         /**
@@ -154,17 +168,29 @@ public class ConfigNode<T> extends ConfigHeaderNode implements ValueNode<T> {
          */
         public @NotNull B name(@Nullable String name) {
             this.name = name;
-            return (B) this;
+            return self();
         }
 
+        /**
+         * Sets the serializer for this node.
+         *
+         * @param serializer    The serializer for this node.
+         * @return This builder.
+         */
         public @NotNull B serializer(@NotNull NodeSerializer<T> serializer) {
             this.serializer = serializer;
-            return (B) this;
+            return self();
         }
 
+        /**
+         * Sets the validator for this node.
+         *
+         * @param validator The validator for this node.
+         * @return This builder.
+         */
         public @NotNull B validator(@NotNull Function<T, Try<Void>> validator) {
             this.validator = validator;
-            return (B) this;
+            return self();
         }
 
         /**
@@ -175,7 +201,7 @@ public class ConfigNode<T> extends ConfigHeaderNode implements ValueNode<T> {
          */
         public @NotNull B onSetValue(@NotNull BiConsumer<T, T> onSetValue) {
             this.onSetValue = onSetValue;
-            return (B) this;
+            return self();
         }
 
         /**
@@ -183,7 +209,13 @@ public class ConfigNode<T> extends ConfigHeaderNode implements ValueNode<T> {
          */
         @Override
         public @NotNull ConfigNode<T> build() {
-            return new ConfigNode<>(path, comments.toArray(new String[0]), name, type, defaultValue, serializer, validator, onSetValue);
+            return new ConfigNode<>(path, comments.toArray(new String[0]),
+                    name, type, defaultValue,serializer, validator, onSetValue);
+        }
+
+        protected @NotNull B self() {
+            //noinspection unchecked
+            return (B) this;
         }
     }
 }