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修复CollUtil.containsAll在coll2长度大于coll1时逻辑歧义问题

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This commit is contained in:
Looly 2024-01-26 16:03:41 +08:00
parent ac255e78b4
commit 4acb828ac7
2 changed files with 48 additions and 7 deletions
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37
hutool-core/src/main/java/org/dromara/hutool/core/collection/CollUtil.java
View File

@ -502,14 +502,16 @@ public class CollUtil {
} }
/** /**
* 集合1中是否包含集合2中所有的元素，即集合2是否为集合1的子集, 不考虑元素的个数<br> * 集合1中是否包含集合2中所有的元素。<br>
* 空集是所有集合的子集<br> * 当集合1和集合2都为空时，返回{@code true}
* 当集合2为空时，返回{@code true}
* *
* @param coll1 集合1 * @param coll1 集合1
* @param coll2 集合2 * @param coll2 集合2
* @return 集合1中是否包含集合2中所有的元素 * @return 集合1中是否包含集合2中所有的元素
* @since 4.5.12 * @since 4.5.12
*/ */
@SuppressWarnings("SuspiciousMethodCalls")
public static boolean containsAll(final Collection<?> coll1, final Collection<?> coll2) { public static boolean containsAll(final Collection<?> coll1, final Collection<?> coll2) {
if (isEmpty(coll1)) { if (isEmpty(coll1)) {
return isEmpty(coll2); return isEmpty(coll2);
@ -519,12 +521,35 @@ public class CollUtil {
return true; return true;
} }
if (coll1.size() < coll2.size()) { // Set直接判定
return false; if(coll1 instanceof Set){
return coll1.containsAll(coll2);
} }
//noinspection SuspiciousMethodCalls // 参考Apache commons collection4
return coll1.containsAll(coll2); // 将时间复杂度降低到O(n + m)
final Iterator<?> it = coll1.iterator();
final Set<Object> elementsAlreadySeen = new HashSet<>(coll1.size(), 1);
for (final Object nextElement : coll2) {
if (elementsAlreadySeen.contains(nextElement)) {
continue;
}
boolean foundCurrentElement = false;
while (it.hasNext()) {
final Object p = it.next();
elementsAlreadySeen.add(p);
if (Objects.equals(nextElement, p)) {
foundCurrentElement = true;
break;
}
}
if (!foundCurrentElement) {
return false;
}
}
return true;
} }
/** /**

18
hutool-core/src/test/java/org/dromara/hutool/core/collection/CollUtilTest.java
View File

@ -408,7 +408,7 @@ public class CollUtilTest {
public void groupTest() { public void groupTest() {
final List<String> list = ListUtil.of("1", "2", "3", "4", "5", "6"); final List<String> list = ListUtil.of("1", "2", "3", "4", "5", "6");
final List<List<String>> group = CollUtil.group(list, null); final List<List<String>> group = CollUtil.group(list, null);
Assertions.assertTrue(group.size() > 0); Assertions.assertFalse(group.isEmpty());
final List<List<String>> group2 = CollUtil.group(list, t -> { final List<List<String>> group2 = CollUtil.group(list, t -> {
// 按照奇数偶数分类 // 按照奇数偶数分类
@ -1266,4 +1266,20 @@ public class CollUtilTest {
Assertions.assertArrayEquals(new String[]{"a", "b", "c", null, "d", "e", "f", "g", "h", "i", "j", "k", "l"}, flat.toArray()); Assertions.assertArrayEquals(new String[]{"a", "b", "c", null, "d", "e", "f", "g", "h", "i", "j", "k", "l"}, flat.toArray());
} }
@Test
void issueI8Z2Q4Test() {
final ArrayList<String> coll1 = new ArrayList<>();
coll1.add("1");
coll1.add("2");
coll1.add("3");
coll1.add("4");
final ArrayList<String> coll2 = new ArrayList<>();
coll2.add("1");
coll2.add("1");
coll2.add("1");
coll2.add("1");
coll2.add("1");
Assertions.assertTrue(CollUtil.containsAll(coll1, coll2));
}
} }