Collections util

src/main/java/ru/bclib/util/CollectionsUtil.java

@@ -0,0 +1,46 @@
+package ru.bclib.util;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+public class CollectionsUtil {
+	/**
+	 * Will return mutable copy of list.
+	 * @param list {@link List} to make mutable.
+	 * @return {@link ArrayList} or original {@link List} if it is mutable.
+	 */
+	public static <E extends Object> List<E> getMutable(List<E> list) {
+		if (list instanceof ArrayList) {
+			return list;
+		}
+		return new ArrayList<>(list);
+	}
+	
+	/**
+	 * Will return mutable copy of set.
+	 * @param set {@link Set} to make mutable.
+	 * @return {@link HashSet} or original {@link Set} if it is mutable.
+	 */
+	public static <E extends Object> Set<E> getMutable(Set<E> set) {
+		if (set instanceof HashSet) {
+			return set;
+		}
+		return new HashSet<>(set);
+	}
+	
+	/**
+	 * Will return mutable copy of map.
+	 * @param map {@link Map} to make mutable.
+	 * @return {@link HashMap} or original {@link Map} if it is mutable.
+	 */
+	public static <K extends Object, V extends Object> Map<K, V> getMutable(Map<K, V> map) {
+		if (map instanceof HashMap) {
+			return map;
+		}
+		return new HashMap<>(map);
+	}
+}