add annotations

Author: OffsetMonkey538

src/main/java/top/offsetmonkey538/offsetutils538/api/annotation/Unmodifiable.java

@@ -0,0 +1,20 @@
+package top.offsetmonkey538.offsetutils538.api.annotation;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Indicates that the annotated {@link java.util.Collection} or {@link java.util.Map} is unmodifiable.
+ * <br>
+ * Mutator methods of annotated elements will throw exceptions or have no effect.
+ * @see UnmodifiableView
+ */
+@Documented
+@Retention(RetentionPolicy.CLASS)
+@Target({ElementType.TYPE_USE})
+public @interface Unmodifiable {
+
+}

src/main/java/top/offsetmonkey538/offsetutils538/api/annotation/UnmodifiableView.java

@@ -0,0 +1,21 @@
+package top.offsetmonkey538.offsetutils538.api.annotation;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Indicates that the annotated {@link java.util.Collection} or {@link java.util.Map} is unmodifiable.
+ * <br>
+ * Mutator methods of annotated elements will throw exceptions or have no effect.
+ * <p>The content of the collection or map could however still be mutated by other code.</p>
+ * @see Unmodifiable
+ */
+@Documented
+@Retention(RetentionPolicy.CLASS)
+@Target({ElementType.TYPE_USE})
+public @interface UnmodifiableView {
+
+}