!790 补充collection.iter包下的测试用例、注释

Merge pull request !790 from Createsequence/fix-coll

hutool-core/src/main/java/cn/hutool/core/collection/iter/CopiedIter.java

@@ -1,8 +1,10 @@
 package cn.hutool.core.collection.iter;
 
 import cn.hutool.core.collection.ListUtil;
+import cn.hutool.core.util.ObjUtil;
 
 import java.io.Serializable;
+import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 
@@ -44,7 +46,7 @@ public class CopiedIter<E> implements IterableIter<E>, Serializable {
 	 * @param iterator 被复制的Iterator
 	 */
 	public CopiedIter(final Iterator<E> iterator) {
-		final List<E> eleList = ListUtil.of(iterator);
+		final List<E> eleList = ListUtil.of(ObjUtil.defaultIfNull(iterator, Collections.emptyIterator()));
 		this.listIterator = eleList.iterator();
 	}
 

hutool-core/src/main/java/cn/hutool/core/collection/iter/FilterIter.java

@@ -32,6 +32,7 @@ public class FilterIter<E> implements Iterator<E> {
 	 *
 	 * @param iterator 被包装的{@link Iterator}
 	 * @param filter   过滤函数，{@code null}表示不过滤
+	 * @throws NullPointerException {@code iterator}为{@code null}时抛出
 	 */
 	public FilterIter(final Iterator<? extends E> iterator, final Predicate<? super E> filter) {
 		this.iterator = Assert.notNull(iterator);

hutool-core/src/main/java/cn/hutool/core/collection/iter/IterUtil.java

@@ -11,16 +11,7 @@ import cn.hutool.core.util.ObjUtil;
 import org.w3c.dom.Node;
 import org.w3c.dom.NodeList;
 
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.Dictionary;
-import java.util.Enumeration;
-import java.util.HashMap;
-import java.util.Iterator;
-import java.util.List;
-import java.util.Map;
-import java.util.Objects;
+import java.util.*;
 import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.function.Predicate;
@@ -198,7 +189,7 @@ public class IterUtil {
 	 * @return 某个字段值与对象对应Map
 	 * @since 4.6.2
 	 */
-	public static <V> List<Object> fieldValueList(final Iterable<V> iterable, final String fieldName) {
+	public static <V, R> List<R> fieldValueList(final Iterable<V> iterable, final String fieldName) {
 		return fieldValueList(getIter(iterable), fieldName);
 	}
 
@@ -211,13 +202,14 @@ public class IterUtil {
 	 * @return 某个字段值与对象对应Map
 	 * @since 4.0.10
 	 */
-	public static <V> List<Object> fieldValueList(final Iterator<V> iter, final String fieldName) {
-		final List<Object> result = new ArrayList<>();
+	@SuppressWarnings("unchecked")
+	public static <V, R> List<R> fieldValueList(final Iterator<V> iter, final String fieldName) {
+		final List<R> result = new ArrayList<>();
 		if (null != iter) {
 			V value;
 			while (iter.hasNext()) {
 				value = iter.next();
-				result.add(FieldUtil.getFieldValue(value, fieldName));
+				result.add((R)FieldUtil.getFieldValue(value, fieldName));
 			}
 		}
 		return result;
@@ -378,7 +370,7 @@ public class IterUtil {
 	}
 
 	/**
-	 * 将列表转成值为List的HashMap
+	 * 将列表转成值为List的Map集合
 	 *
 	 * @param resultMap   结果Map，可自定义结果Map类型
 	 * @param iterable    值列表
@@ -702,38 +694,40 @@ public class IterUtil {
 	}
 
 	/**
-	 * 判断两个{@link Iterable} 是否元素和顺序相同，返回{@code true}的条件是：
+	 * <p>判断两个{@link Iterable}中的元素与其顺序是否相同 <br>
+	 * 当满足下列情况时返回{@code true}：
 	 * <ul>
-	 *     <li>两个{@link Iterable}必须长度相同</li>
-	 *     <li>两个{@link Iterable}元素相同index的对象必须equals，满足{@link Objects#equals(Object, Object)}</li>
+	 *     <li>两个{@link Iterable}都为{@code null}；</li>
+	 *     <li>两个{@link Iterable}满足{@code iterable1 == iterable2}；</li>
+	 *     <li>两个{@link Iterable}所有具有相同下标的元素皆满足{@link Objects#equals(Object, Object)}；</li>
 	 * </ul>
 	 * 此方法来自Apache-Commons-Collections4。
 	 *
-	 * @param list1 列表1
-	 * @param list2 列表2
+	 * @param iterable1 列表1
+	 * @param iterable2 列表2
 	 * @return 是否相同
 	 * @since 5.6.0
 	 */
-	public static boolean isEqualList(final Iterable<?> list1, final Iterable<?> list2) {
-		if (list1 == list2) {
+	public static boolean isEqualList(final Iterable<?> iterable1, final Iterable<?> iterable2) {
+		if (iterable1 == iterable2) {
 			return true;
 		}
-
-		final Iterator<?> it1 = list1.iterator();
-		final Iterator<?> it2 = list2.iterator();
+		if (iterable1 == null || iterable2 == null) {
+			return false;
+		}
+		final Iterator<?> iter1 = iterable1.iterator();
+		final Iterator<?> iter2 = iterable2.iterator();
 		Object obj1;
 		Object obj2;
-		while (it1.hasNext() && it2.hasNext()) {
-			obj1 = it1.next();
-			obj2 = it2.next();
-
+		while (iter1.hasNext() && iter2.hasNext()) {
+			obj1 = iter1.next();
+			obj2 = iter2.next();
 			if (false == Objects.equals(obj1, obj2)) {
 				return false;
 			}
 		}
-
 		// 当两个Iterable长度不一致时返回false
-		return false == (it1.hasNext() || it2.hasNext());
+		return false == (iter1.hasNext() || iter2.hasNext());
 	}
 
 	/**

hutool-core/src/main/java/cn/hutool/core/collection/iter/IterableIter.java

@@ -15,4 +15,5 @@ public interface IterableIter<T> extends Iterable<T>, Iterator<T> {
 	default Iterator<T> iterator() {
 		return this;
 	}
+
 }

hutool-core/src/main/java/cn/hutool/core/collection/iter/IteratorEnumeration.java

@@ -16,6 +16,8 @@ public class IteratorEnumeration<E> implements Enumeration<E>, Serializable{
 
 	private final Iterator<E> iterator;
 
+
+
 	/**
 	 * 构造
 	 * @param iterator {@link Iterator}对象

hutool-core/src/main/java/cn/hutool/core/collection/partition/AvgPartition.java

@@ -1,6 +1,5 @@
 package cn.hutool.core.collection.partition;
 
-import cn.hutool.core.collection.partition.Partition;
 import cn.hutool.core.lang.Assert;
 
 import java.util.List;

hutool-core/src/test/java/cn/hutool/core/collection/iter/EnumerationIterTest.java

@@ -0,0 +1,46 @@
+package cn.hutool.core.collection.iter;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Enumeration;
+
+/**
+ * @author huangchengxing
+ */
+public class EnumerationIterTest {
+
+	@Test
+	public void testHasNext() {
+		Enumeration<Integer> enumeration = new IteratorEnumeration<>(Arrays.asList(1, 2, 3).iterator());
+		EnumerationIter<Integer> iter = new EnumerationIter<>(enumeration);
+		Assert.assertTrue(iter.hasNext());
+		Assert.assertFalse(new EnumerationIter<>(new IteratorEnumeration<>(Collections.emptyIterator())).hasNext());
+	}
+
+	@Test
+	public void testNext() {
+		Enumeration<Integer> enumeration = new IteratorEnumeration<>(Arrays.asList(1, 2, 3).iterator());
+		EnumerationIter<Integer> iter = new EnumerationIter<>(enumeration);
+		Assert.assertEquals((Integer)1, iter.next());
+		Assert.assertEquals((Integer)2, iter.next());
+		Assert.assertEquals((Integer)3, iter.next());
+	}
+
+	@Test
+	public void testRemove() {
+		Enumeration<Integer> enumeration = new IteratorEnumeration<>(Arrays.asList(1, 2, 3).iterator());
+		EnumerationIter<Integer> iter = new EnumerationIter<>(enumeration);
+		Assert.assertThrows(UnsupportedOperationException.class, iter::remove);
+	}
+
+	@Test
+	public void testIterator() {
+		Enumeration<Integer> enumeration = new IteratorEnumeration<>(Arrays.asList(1, 2, 3).iterator());
+		EnumerationIter<Integer> iter = new EnumerationIter<>(enumeration);
+		Assert.assertSame(iter, iter.iterator());
+	}
+
+}

hutool-core/src/test/java/cn/hutool/core/collection/iter/IterChainTest.java

@@ -13,17 +13,20 @@ import java.util.Iterator;
 public class IterChainTest {
 
 	@Test
-	public void addChain() {
+	public void testAddChain() {
 		Iterator<Integer> iter1 = Arrays.asList(1, 2).iterator();
 		Iterator<Integer> iter2 = Arrays.asList(3, 4).iterator();
 		IterChain<Integer> iterChain = new IterChain<>();
 		Assert.assertSame(iterChain, iterChain.addChain(iter1));
 		Assert.assertSame(iterChain, iterChain.addChain(iter2));
 		Assert.assertEquals(2, iterChain.allIterators.size());
+
+		iterChain = new IterChain<>(iter1, iter2);
+		Assert.assertEquals(2, iterChain.allIterators.size());
 	}
 
 	@Test
-	public void hasNext() {
+	public void testHasNext() {
 		IterChain<Integer> iterChain = new IterChain<>();
 		Assert.assertFalse(iterChain.hasNext());
 		Assert.assertFalse(iterChain.addChain(Collections.emptyIterator()).hasNext());
@@ -31,7 +34,7 @@ public class IterChainTest {
 	}
 
 	@Test
-	public void next() {
+	public void testNext() {
 		Iterator<Integer> iter1 = Arrays.asList(1, 2).iterator();
 		Iterator<Integer> iter2 = Arrays.asList(3, 4).iterator();
 		IterChain<Integer> iterChain = new IterChain<>();
@@ -44,14 +47,14 @@ public class IterChainTest {
 	}
 
 	@Test
-	public void remove() {
+	public void testRemove() {
 		IterChain<Integer> iterChain = new IterChain<>();
 		iterChain.addChain(Arrays.asList(1, 2).iterator());
 		Assert.assertThrows(IllegalStateException.class, iterChain::remove);
 	}
 
 	@Test
-	public void iterator() {
+	public void testIterator() {
 		Iterator<Integer> iter1 = Arrays.asList(1, 2).iterator();
 		Iterator<Integer> iter2 = Arrays.asList(3, 4).iterator();
 		IterChain<Integer> iterChain = new IterChain<>();

hutool-core/src/test/java/cn/hutool/core/collection/iter/IterUtilTest.java

@@ -1,12 +1,12 @@
 package cn.hutool.core.collection.iter;
 
+import lombok.RequiredArgsConstructor;
 import org.junit.Assert;
 import org.junit.Test;
+import org.w3c.dom.NodeList;
 
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.Iterator;
-import java.util.Map;
+import java.util.*;
+import java.util.function.Function;
 
 /**
  * test for {@link IterUtil}
@@ -17,6 +17,13 @@ public class IterUtilTest {
 	public void testGetIter() {
 		Assert.assertNull(IterUtil.getIter(null));
 		Assert.assertEquals(Collections.emptyIterator(), IterUtil.getIter(Collections.emptyList()));
+
+		Assert.assertNull(IterUtil.getIter((Object)null));
+		Assert.assertNotNull(IterUtil.getIter(Collections.emptyIterator()));
+		Assert.assertNotNull(IterUtil.getIter((Object)Collections.emptyList()));
+		Assert.assertNotNull(IterUtil.getIter(new Integer[0]));
+		Assert.assertNotNull(IterUtil.getIter(Collections.emptyMap()));
+		Assert.assertNull(IterUtil.getIter((NodeList)null));
 	}
 
 	@Test
@@ -64,4 +71,236 @@ public class IterUtilTest {
 		Assert.assertEquals((Integer)1, countMap.get(o2));
 	}
 
+	@Test
+	public void testFieldValueMap() {
+		Bean bean1 = new Bean(1, "A");
+		Bean bean2 = new Bean(2, "B");
+		Map<Integer, Bean> map = IterUtil.fieldValueMap(Arrays.asList(bean1, bean2).iterator(), "id");
+		Assert.assertEquals(bean1, map.get(1));
+		Assert.assertEquals(bean2, map.get(2));
+	}
+
+	@Test
+	public void testFieldValueAsMap() {
+		Bean bean1 = new Bean(1, "A");
+		Bean bean2 = new Bean(2, "B");
+		Map<Integer, String> map = IterUtil.fieldValueAsMap(
+			Arrays.asList(bean1, bean2).iterator(), "id", "name"
+		);
+		Assert.assertEquals("A", map.get(1));
+		Assert.assertEquals("B", map.get(2));
+	}
+
+	@Test
+	public void testFieldValueList() {
+		Bean bean1 = new Bean(1, "A");
+		Bean bean2 = new Bean(2, "B");
+		Assert.assertEquals(Arrays.asList(1, 2), IterUtil.fieldValueList(Arrays.asList(bean1, bean2), "id"));
+		Assert.assertEquals(
+			Arrays.asList(1, 2),
+			IterUtil.fieldValueList(Arrays.asList(bean1, bean2).iterator(), "id")
+		);
+	}
+
+	@Test
+	public void testJoin() {
+		List<String> stringList = Arrays.asList("1", "2", "3");
+		Assert.assertEquals("123", IterUtil.join(stringList.iterator(), ""));
+		Assert.assertEquals("-1--2--3-", IterUtil.join(stringList.iterator(), "", "-", "-"));
+		Assert.assertEquals("123", IterUtil.join(stringList.iterator(), "", Function.identity()));
+	}
+
+	@Test
+	public void testToMap() {
+		List<Integer> keys = Arrays.asList(1, 2, 3);
+
+		Map<Integer, Integer> map = IterUtil.toMap(keys, keys);
+		Assert.assertEquals(keys, new ArrayList<>(map.keySet()));
+		Assert.assertEquals(keys, new ArrayList<>(map.values()));
+
+		map = IterUtil.toMap(keys.iterator(), keys.iterator());
+		Assert.assertEquals(keys, new ArrayList<>(map.keySet()));
+		Assert.assertEquals(keys, new ArrayList<>(map.values()));
+
+		map = IterUtil.toMap(keys.iterator(), keys.iterator(), true);
+		Assert.assertEquals(keys, new ArrayList<>(map.keySet()));
+		Assert.assertEquals(keys, new ArrayList<>(map.values()));
+
+		map = IterUtil.toMap(keys, keys, true);
+		Assert.assertEquals(keys, new ArrayList<>(map.keySet()));
+		Assert.assertEquals(keys, new ArrayList<>(map.values()));
+
+		map = IterUtil.toMap(keys, Function.identity());
+		Assert.assertEquals(keys, new ArrayList<>(map.keySet()));
+		Assert.assertEquals(keys, new ArrayList<>(map.values()));
+
+		map = IterUtil.toMap(keys, Function.identity(), Function.identity());
+		Assert.assertEquals(keys, new ArrayList<>(map.keySet()));
+		Assert.assertEquals(keys, new ArrayList<>(map.values()));
+	}
+
+	@Test
+	public void testToListMap() {
+		List<Integer> keys = Arrays.asList(1, 2, 3, 4);
+
+		Map<Boolean, List<Integer>> map = IterUtil.toListMap(keys, i -> (i & 1) == 0, Function.identity());
+		Assert.assertEquals(Arrays.asList(2, 4), map.get(true));
+		Assert.assertEquals(Arrays.asList(1, 3), map.get(false));
+
+		map = IterUtil.toListMap(keys, i -> (i & 1) == 0);
+		Assert.assertEquals(Arrays.asList(2, 4), map.get(true));
+		Assert.assertEquals(Arrays.asList(1, 3), map.get(false));
+
+		map = new LinkedHashMap<>();
+		Map<Boolean, List<Integer>> rawMap = IterUtil.toListMap(map, keys, i -> (i & 1) == 0, Function.identity());
+		Assert.assertSame(rawMap, map);
+		Assert.assertEquals(Arrays.asList(2, 4), rawMap.get(true));
+		Assert.assertEquals(Arrays.asList(1, 3), rawMap.get(false));
+	}
+
+	@Test
+	public void testAsIterable() {
+		Iterator<Integer> iter = Arrays.asList(1, 2, 3).iterator();
+		Assert.assertEquals(iter, IterUtil.asIterable(iter).iterator());
+		Assert.assertNull(IterUtil.asIterable(null).iterator());
+
+		Enumeration<Integer> enumeration = new IteratorEnumeration<>(iter);
+		Iterator<Integer> iter2 = IterUtil.asIterator(enumeration);
+		Assert.assertEquals((Integer)1, iter2.next());
+		Assert.assertEquals((Integer)2, iter2.next());
+		Assert.assertEquals((Integer)3, iter2.next());
+	}
+
+	@Test
+	public void testGet() {
+		Iterator<Integer> iter = Arrays.asList(1, 2, 3, 4).iterator();
+		Assert.assertEquals((Integer)3, IterUtil.get(iter, 2));
+		Assert.assertThrows(IllegalArgumentException.class, () -> IterUtil.get(iter, -1));
+	}
+
+	@Test
+	public void testGetFirst() {
+		Iterator<Integer> iter = Arrays.asList(1, 2, 3, 4).iterator();
+		Assert.assertEquals((Integer)1, IterUtil.getFirst(iter));
+		Assert.assertNull(IterUtil.getFirst(null));
+		Assert.assertNull(IterUtil.getFirst(Collections.emptyIterator()));
+
+		Assert.assertEquals((Integer)2, IterUtil.getFirst(iter, t -> (t & 1) == 0));
+		Assert.assertNull(IterUtil.getFirst((Iterator<Integer>)null, t -> (t & 1) == 0));
+		Assert.assertNull(IterUtil.getFirst(Collections.emptyIterator(), Objects::nonNull));
+	}
+
+	@Test
+	public void testGetFirstNoneNull() {
+		Iterator<Integer> iter = Arrays.asList(null, 2, null, 4).iterator();
+		Assert.assertEquals((Integer)2, IterUtil.getFirstNoneNull(iter));
+		Assert.assertNull(IterUtil.getFirstNoneNull(null));
+		Assert.assertNull(IterUtil.getFirstNoneNull(Collections.emptyIterator()));
+	}
+
+	@Test
+	public void testGetElementType() {
+		List<Object> list = Arrays.asList(null, "str", null);
+		Assert.assertEquals(String.class, IterUtil.getElementType(list));
+		Assert.assertNull(IterUtil.getElementType((Iterable<?>)null));
+		Assert.assertNull(IterUtil.getElementType(Collections.emptyList()));
+
+		Assert.assertEquals(String.class, IterUtil.getElementType(list.iterator()));
+		Assert.assertNull(IterUtil.getElementType((Iterator<?>)null));
+		Assert.assertNull(IterUtil.getElementType(Collections.emptyIterator()));
+	}
+
+	@Test
+	public void testEdit() {
+		Assert.assertEquals(
+			Collections.singletonList("str"),
+			IterUtil.edit(Arrays.asList(null, "str", null).iterator(), t -> t)
+		);
+		Assert.assertEquals(
+			Collections.singletonList("str"),
+			IterUtil.edit(Arrays.asList(null, "str", null).iterator(), null)
+		);
+		Assert.assertEquals(Collections.emptyList(), IterUtil.edit(null, t -> t));
+	}
+
+	@Test
+	public void testRemove() {
+		List<Integer> list = new ArrayList<>(Arrays.asList(1, null, null, 3));
+		IterUtil.remove(list.iterator(), Objects::isNull);
+		Assert.assertEquals(Arrays.asList(1, 3), list);
+	}
+
+	@Test
+	public void testFilterToList() {
+		List<Integer> list1 = new ArrayList<>(Arrays.asList(1, null, null, 3));
+		List<Integer> list2 = IterUtil.filterToList(list1.iterator(), Objects::nonNull);
+		Assert.assertSame(list1, list1);
+		Assert.assertEquals(Arrays.asList(1, 3), list2);
+	}
+
+	@Test
+	public void testFiltered() {
+		Assert.assertNotNull(IterUtil.filtered(Collections.emptyIterator(), t -> true));
+	}
+
+	@Test
+	public void testEmpty() {
+		Assert.assertSame(Collections.emptyIterator(), IterUtil.empty());
+	}
+
+	@Test
+	public void testTrans() {
+		Assert.assertNotNull(IterUtil.trans(Collections.emptyIterator(), t -> true));
+	}
+
+	@Test
+	public void testSize() {
+		Assert.assertEquals(0, IterUtil.size((Iterator<?>)null));
+		Assert.assertEquals(0, IterUtil.size(Collections.emptyIterator()));
+		Assert.assertEquals(3, IterUtil.size(Arrays.asList(1, 2, 3).iterator()));
+
+		Assert.assertEquals(0, IterUtil.size((Iterable<?>)null));
+		Assert.assertEquals(0, IterUtil.size(Collections.emptyList()));
+		Assert.assertEquals(3, IterUtil.size(Arrays.asList(1, 2, 3)));
+	}
+
+	@Test
+	public void testIsEqualList() {
+		Assert.assertFalse(IterUtil.isEqualList(null, Collections.emptyList()));
+		Assert.assertFalse(IterUtil.isEqualList(Arrays.asList(1, 2, 3), Collections.emptyList()));
+		Assert.assertFalse(IterUtil.isEqualList(Arrays.asList(1, 2, 3), Arrays.asList(1, 2)));
+		Assert.assertTrue(IterUtil.isEqualList(Arrays.asList(1, 2, 3), Arrays.asList(1, 2, 3)));
+		Assert.assertTrue(IterUtil.isEqualList(null, null));
+		Assert.assertTrue(IterUtil.isEqualList(Collections.emptyList(), Collections.emptyList()));
+	}
+
+	@Test
+	public void testClear() {
+		List<Integer> list = new ArrayList<>(Arrays.asList(1, 2, 3));
+		IterUtil.clear(list.iterator());
+		Assert.assertTrue(list.isEmpty());
+		Assert.assertThrows(UnsupportedOperationException.class, () -> IterUtil.clear(Arrays.asList(1, 2).iterator()));
+	}
+
+	@Test
+	public void testToStr() {
+		List<Integer> list = Arrays.asList(1, 2, 3);
+		Assert.assertEquals("[1, 2, 3]", IterUtil.toStr(list.iterator()));
+		Assert.assertEquals("[1, 2, 3]", IterUtil.toStr(list.iterator(), Objects::toString));
+		Assert.assertEquals("{1:2:3}", IterUtil.toStr(list.iterator(), Objects::toString, ":", "{", "}"));
+	}
+
+	@Test
+	public void testForEach() {
+		List<Integer> list = new ArrayList<>();
+		IterUtil.forEach(Arrays.asList(1, 2, 3, 4).iterator(), list::add);
+		Assert.assertEquals(Arrays.asList(1, 2, 3, 4), list);
+	}
+
+	@RequiredArgsConstructor
+	private static class Bean {
+		private final Integer id;
+		private final String name;
+	}
+
 }

hutool-core/src/test/java/cn/hutool/core/collection/iter/IteratorEnumerationTest.java

@@ -0,0 +1,32 @@
+package cn.hutool.core.collection.iter;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * test for {@link IteratorEnumeration}
+ */
+public class IteratorEnumerationTest {
+
+	@Test
+	public void testHasMoreElements() {
+		List<Integer> list = Arrays.asList(1, 2, 3);
+		IteratorEnumeration<Integer> enumeration = new IteratorEnumeration<>(list.iterator());
+		Assert.assertTrue(enumeration.hasMoreElements());
+		Assert.assertFalse(new IteratorEnumeration<>(Collections.emptyIterator()).hasMoreElements());
+	}
+
+	@Test
+	public void testNextElement() {
+		List<Integer> list = Arrays.asList(1, 2, 3);
+		IteratorEnumeration<Integer> enumeration = new IteratorEnumeration<>(list.iterator());
+		Assert.assertEquals((Integer)1, enumeration.nextElement());
+		Assert.assertEquals((Integer)2, enumeration.nextElement());
+		Assert.assertEquals((Integer)3, enumeration.nextElement());
+	}
+
+}

hutool-core/src/test/java/cn/hutool/core/collection/iter/LineIterTest.java

@@ -0,0 +1,68 @@
+package cn.hutool.core.collection.iter;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.io.*;
+import java.net.URL;
+import java.nio.charset.StandardCharsets;
+import java.util.NoSuchElementException;
+
+/**
+ * test for {@link LineIter}
+ */
+public class LineIterTest {
+
+	@Test
+	public void testHasNext() {
+		LineIter iter = getItrFromClasspathFile();
+		Assert.assertTrue(iter.hasNext());
+	}
+
+	@Test
+	public void testNext() {
+		LineIter iter = getItrFromClasspathFile();
+		Assert.assertEquals("is first line", iter.next());
+		Assert.assertEquals("is second line", iter.next());
+		Assert.assertEquals("is third line", iter.next());
+	}
+
+	@Test
+	public void testRemove() {
+		LineIter iter = getItrFromClasspathFile();
+		iter.next();
+		Assert.assertThrows(UnsupportedOperationException.class, iter::remove);
+	}
+
+	@Test
+	public void testFinish() {
+		LineIter iter = getItrFromClasspathFile();
+		iter.finish();
+		Assert.assertThrows(NoSuchElementException.class, iter::next);
+	}
+
+	@Test
+	public void testClose() throws IOException {
+		URL url = LineIterTest.class.getClassLoader().getResource("text.txt");
+		Assert.assertNotNull(url);
+		FileInputStream inputStream = new FileInputStream(url.getFile());
+		LineIter iter = new LineIter(inputStream, StandardCharsets.UTF_8);
+		iter.close();
+		Assert.assertThrows(NoSuchElementException.class, iter::next);
+		Assert.assertThrows(IOException.class, inputStream::read);
+	}
+
+	private static LineIter getItrFromClasspathFile() {
+		URL url = LineIterTest.class.getClassLoader().getResource("text.txt");
+		Assert.assertNotNull(url);
+		FileInputStream inputStream = null;
+		try {
+			inputStream = new FileInputStream(url.getFile());
+		} catch (FileNotFoundException e) {
+			e.printStackTrace();
+		}
+		BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
+		return new LineIter(bufferedReader);
+	}
+
+}

hutool-core/src/test/java/cn/hutool/core/collection/iter/PartitionIterTest.java

@@ -13,7 +13,7 @@ import java.util.Iterator;
 public class PartitionIterTest {
 
 	@Test
-	public void hasNext() {
+	public void testHasNext() {
 		Iterator<Integer> iter = Arrays.asList(1, 2, 3, 4).iterator();
 		PartitionIter<Integer> partitionIter = new PartitionIter<>(iter, 2);
 		Assert.assertTrue(partitionIter.hasNext());
@@ -21,7 +21,7 @@ public class PartitionIterTest {
 	}
 
 	@Test
-	public void next() {
+	public void testNext() {
 		Iterator<Integer> iter = Arrays.asList(1, 2, 3, 4).iterator();
 		PartitionIter<Integer> partitionIter = new PartitionIter<>(iter, 2);
 		Assert.assertEquals(Arrays.asList(1, 2), partitionIter.next());

hutool-core/src/test/java/cn/hutool/core/collection/iter/TransIterTest.java

@@ -0,0 +1,44 @@
+package cn.hutool.core.collection.iter;
+
+import cn.hutool.core.collection.ListUtil;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.function.Function;
+
+/**
+ * @author huangchengxing
+ */
+public class TransIterTest {
+
+	@Test
+	public void testHasNext() {
+		TransIter<Integer, String> iter = new TransIter<>(Arrays.asList(1, 2, 3).iterator(), String::valueOf);
+		Assert.assertTrue(iter.hasNext());
+		Assert.assertFalse(new TransIter<>(Collections.emptyIterator(), Function.identity()).hasNext());
+	}
+
+	@Test
+	public void testNext() {
+		TransIter<Integer, String> iter = new TransIter<>(Arrays.asList(1, 2, 3).iterator(), String::valueOf);
+		Assert.assertEquals("1", iter.next());
+		Assert.assertEquals("2", iter.next());
+		Assert.assertEquals("3", iter.next());
+	}
+
+	@Test
+	public void testRemove() {
+		List<Integer> list = ListUtil.of(1, 2, 3);
+		TransIter<Integer, String> iter = new TransIter<>(list.iterator(), String::valueOf);
+		iter.next();
+		iter.remove();
+		iter.next();
+		iter.remove();
+		iter.next();
+		iter.remove();
+		Assert.assertTrue(list.isEmpty());
+	}
+}

hutool-core/src/test/resources/text.txt

@@ -0,0 +1,3 @@
+is first line
+is second line
+is third line