add method

huchangyao · Sep 17, 2021 · b935ace · b935ace
1 parent 2f57c2a
commit b935ace
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Showing 5 changed files with 62 additions and 52 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -11,6 +11,7 @@
 * 【core   】     CsvWriter的write和writeBeans参数改为Iterable（issue#I49O4S@Gitee）
 * 【core   】     BitStatusUtil添加来源声明（issue#1824@Github）
 * 【core   】     UrlQuery.build增加重载，支持可选是否转义（issue#I4AIX1@Gitee）
+* 【core   】     ListUtil增加swapTo和swapElement方法（pr#416@Gitee）
 * 
 ### 🐞Bug修复
 * 【core   】     修复FuncKey函数无效问题

diff --git a/hutool-core/src/main/java/cn/hutool/core/collection/CollUtil.java b/hutool-core/src/main/java/cn/hutool/core/collection/CollUtil.java
@@ -2954,34 +2954,4 @@ public static boolean isEqualList(final Collection<?> list1, final Collection<?>
 
 		return IterUtil.isEqualList(list1, list2);
 	}
-
-	/**
-	 * 将指定元素交换到指定索引位置,其他元素的索引值不变
-	 * 交换会修改原List
-	 *
-	 * @param list        列表
-	 * @param element     需交换元素
-	 * @param targetIndex 目标索引
-	 */
-	public static <T> void swapIndex(List<T> list, T element, Integer targetIndex) {
-		if (isEmpty(list) || !list.contains(element)) {
-			return;
-		}
-		Collections.swap(list, list.indexOf(element), targetIndex);
-	}
-
-	/**
-	 * 将指定元素交换到指定元素位置,其他元素的索引值不变
-	 * 交换会修改原List
-	 *
-	 * @param list          列表
-	 * @param element       需交换元素
-	 * @param targetElement 目标元素
-	 */
-	public static <T> void swapElement(List<T> list, T element, T targetElement) {
-		if (isEmpty(list) || !list.contains(targetElement)) {
-			return;
-		}
-		swapIndex(list, element, list.indexOf(targetElement));
-	}
 }
diff --git a/hutool-core/src/main/java/cn/hutool/core/collection/ListUtil.java b/hutool-core/src/main/java/cn/hutool/core/collection/ListUtil.java
@@ -312,7 +312,7 @@ public static <T> void page(List<T> list, int pageSize, Consumer<List<T>> pageLi
 	 * @see Collections#sort(List, Comparator)
 	 */
 	public static <T> List<T> sort(List<T> list, Comparator<? super T> c) {
-		if(CollUtil.isEmpty(list)){
+		if (CollUtil.isEmpty(list)) {
 			return list;
 		}
 		list.sort(c);
@@ -593,4 +593,41 @@ public static <T> List<List<T>> splitAvg(List<T> list, int limit) {
 				? new RandomAccessAvgPartition<>(list, limit)
 				: new AvgPartition<>(list, limit);
 	}
+
+	/**
+	 * 将指定元素交换到指定索引位置,其他元素的索引值不变<br>
+	 * 交换会修改原List<br>
+	 * 如果集合中有多个相同元素，只交换第一个找到的元素
+	 *
+	 * @param list        列表
+	 * @param element     需交换元素
+	 * @param targetIndex 目标索引
+	 * @since 5.7.13
+	 */
+	public static <T> void swapTo(List<T> list, T element, Integer targetIndex) {
+		if (CollUtil.isNotEmpty(list)) {
+			final int index = list.indexOf(element);
+			if (index > 0) {
+				Collections.swap(list, index, targetIndex);
+			}
+		}
+	}
+
+	/**
+	 * 将指定元素交换到指定元素位置,其他元素的索引值不变<br>
+	 * 交换会修改原List<br>
+	 * 如果集合中有多个相同元素，只交换第一个找到的元素
+	 *
+	 * @param list          列表
+	 * @param element       需交换元素
+	 * @param targetElement 目标元素
+	 */
+	public static <T> void swapElement(List<T> list, T element, T targetElement) {
+		if (CollUtil.isNotEmpty(list)) {
+			final int targetIndex = list.indexOf(targetElement);
+			if (targetIndex > 0) {
+				swapTo(list, element, targetIndex);
+			}
+		}
+	}
 }
diff --git a/hutool-core/src/test/java/cn/hutool/core/collection/CollUtilTest.java b/hutool-core/src/test/java/cn/hutool/core/collection/CollUtilTest.java
@@ -772,25 +772,4 @@ public void sortComparableTest() {
 		final List<String> sort = CollUtil.sort(of, new ComparableComparator<>());
 		Assert.assertEquals("a,b,c", CollUtil.join(sort, ","));
 	}
-
-	@Test
-	public void swapIndex() {
-		List<Integer> list = Arrays.asList(7, 2, 8, 9);
-		CollUtil.swapIndex(list, 8, 1);
-		Assert.assertTrue(list.get(1) == 8);
-	}
-
-	@Test
-	public void swapElement() {
-		Map<String, String> map1 = new HashMap<>();
-		map1.put("1", "张三");
-		Map<String, String> map2 = new HashMap<>();
-		map2.put("2", "李四");
-		Map<String, String> map3 = new HashMap<>();
-		map3.put("3", "王五");
-		List<Map<String, String>> list = Arrays.asList(map1, map2, map3);
-		CollUtil.swapElement(list, map2, map3);
-		Map<String, String> map = list.get(2);
-		Assert.assertTrue(map.get("2").equals("李四"));
-	}
 }
diff --git a/hutool-core/src/test/java/cn/hutool/core/collection/ListUtilTest.java b/hutool-core/src/test/java/cn/hutool/core/collection/ListUtilTest.java
@@ -12,7 +12,9 @@
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
 public class ListUtilTest {
 
@@ -202,4 +204,25 @@ class TestBean{
 		Assert.assertEquals("test4", order.get(3).getName());
 		Assert.assertEquals("test5", order.get(4).getName());
 	}
+
+	@Test
+	public void swapIndex() {
+		List<Integer> list = Arrays.asList(7, 2, 8, 9);
+		ListUtil.swapTo(list, 8, 1);
+		Assert.assertEquals(8, (int) list.get(1));
+	}
+
+	@Test
+	public void swapElement() {
+		Map<String, String> map1 = new HashMap<>();
+		map1.put("1", "张三");
+		Map<String, String> map2 = new HashMap<>();
+		map2.put("2", "李四");
+		Map<String, String> map3 = new HashMap<>();
+		map3.put("3", "王五");
+		List<Map<String, String>> list = Arrays.asList(map1, map2, map3);
+		ListUtil.swapElement(list, map2, map3);
+		Map<String, String> map = list.get(2);
+		Assert.assertEquals("李四", map.get("2"));
+	}
 }