feat(loader): Refactor loaders and metadata.

features/commentable/src/main/java/cc/carm/lib/configuration/annotation/HeaderComment.java

@@ -0,0 +1,40 @@
+package cc.carm.lib.configuration.annotation;
+
+import org.jetbrains.annotations.NotNull;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Header Comments.
+ * Add a comment to the top of the corresponding configuration for easy reading and viewing.
+ * <p>e.g.
+ * <blockquote><pre>
+ * # The first line of the comment
+ * # The second line of the comment
+ * foo: "bar"
+ * </pre></blockquote>
+ */
+@Target({ElementType.TYPE, ElementType.FIELD})
+@Retention(RetentionPolicy.RUNTIME)
+public @interface HeaderComment {
+
+    /**
+     * If the content of the note is 0, it will be treated as a blank line.
+     * <p> e.g. <b>{"foo","","bar"}</b>
+     * Will be set as
+     * <blockquote><pre>
+     * # foo
+     *
+     * # bar
+     * foo: "bar"
+     * </pre></blockquote>
+     *
+     * @return The content of this comment
+     */
+    @NotNull
+    String[] value() default "";
+
+}

features/commentable/src/main/java/cc/carm/lib/configuration/annotation/InlineComment.java

@@ -0,0 +1,34 @@
+package cc.carm.lib.configuration.annotation;
+
+import org.jetbrains.annotations.NotNull;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Inline comments,
+ * add comments to the rows of the corresponding configurations for easy reading and viewing.
+ * e.g.
+ * <blockquote><pre>
+ * foo: "bar" # Comment Contents
+ * </pre></blockquote>
+ */
+@Target({ElementType.FIELD})
+@Retention(RetentionPolicy.RUNTIME)
+public @interface InlineComment {
+
+    /**
+     * If the content length is 0, the comment will not be added.
+     * <p> e.g. <b>"foobar"</b> will be set
+     * <blockquote><pre>
+     * foo: "bar" # foobar
+     * </pre></blockquote>
+     *
+     * @return The content of this comment
+     */
+    @NotNull
+    String value() default "";
+
+}

features/commentable/src/main/java/cc/carm/lib/configuration/commentable/CommentableMetaTypes.java

@@ -0,0 +1,22 @@
+package cc.carm.lib.configuration.commentable;
+
+import cc.carm.lib.configuration.annotation.HeaderComment;
+import cc.carm.lib.configuration.annotation.InlineComment;
+import cc.carm.lib.configuration.value.meta.ValueMetaType;
+
+import java.util.Collections;
+import java.util.List;
+
+public interface CommentableMetaTypes {
+
+    /**
+     * Configuration's {@link HeaderComment}
+     */
+    ValueMetaType<List<String>> HEADER_COMMENTS = ValueMetaType.of(Collections.emptyList());
+
+    /**
+     * Configuration's {@link InlineComment}
+     */
+    ValueMetaType<String> INLINE_COMMENT_VALUE = ValueMetaType.of();
+
+}

features/commentable/src/main/java/cc/carm/lib/configuration/commentable/ConfigurationComments.java

@@ -0,0 +1,48 @@
+package cc.carm.lib.configuration.commentable;
+
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.jetbrains.annotations.Unmodifiable;
+
+import java.util.*;
+
+public class ConfigurationComments {
+
+    protected final @NotNull Map<String, List<String>> headerComments = new HashMap<>();
+    protected final @NotNull Map<String, String> inlineComments = new HashMap<>();
+
+    protected @NotNull Map<String, List<String>> getHeaderComments() {
+        return headerComments;
+    }
+
+    protected @NotNull Map<String, String> getInlineComments() {
+        return inlineComments;
+    }
+
+    public void setHeaderComments(@Nullable String path, @Nullable List<String> comments) {
+        if (comments == null) {
+            getHeaderComments().remove(path);
+        } else {
+            getHeaderComments().put(path, comments);
+        }
+    }
+
+    public void setInlineComment(@NotNull String path, @Nullable String comment) {
+        if (comment == null) {
+            getInlineComments().remove(path);
+        } else {
+            getInlineComments().put(path, comment);
+        }
+    }
+
+    @Nullable
+    @Unmodifiable
+    public List<String> getHeaderComment(@Nullable String path) {
+        return Optional.ofNullable(getHeaderComments().get(path)).map(Collections::unmodifiableList).orElse(null);
+    }
+
+    public @Nullable String getInlineComment(@NotNull String path) {
+        return getInlineComments().get(path);
+    }
+
+}

features/commentable/src/main/java/cc/carm/lib/configuration/option/CommentableOptions.java

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+package cc.carm.lib.configuration.option;
+
+import cc.carm.lib.easyoptions.OptionType;
+
+public interface CommentableOptions {
+
+    /**
+     * Whether to keep modified comments in configuration,
+     * that means we only set comments for values that are not exists in configuration.
+     */
+    OptionType<Boolean> KEEP_COMMENTS = OptionType.of(true);
+
+    /**
+     * Whether to comment values name that are not exists in configuration and no default value offered.
+     * <br>If true, a value without default value is not exists in configuration, we will comment its name,
+     * <p>e.g. a value named "foo" without default value will be put as:
+     * <blockquote><pre>
+     * # Value comments
+     * # foo:
+     * </pre></blockquote>
+     */
+    OptionType<Boolean> COMMENT_NO_DEFAULT = OptionType.of(true);
+
+}