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优化FastStream实现细节, 使用高效一些的写法;

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This commit is contained in:
Zjp
2022-08-01 16:25:07 +08:00
parent 4f32f20ea9
commit 9a7367ffe1
4 changed files with 298 additions and 135 deletions
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104
hutool-core/src/test/java/cn/hutool/core/stream/FastStreamTest.java
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@@ -1,10 +1,13 @@
package cn.hutool.core.stream;
import cn.hutool.core.collection.ListUtil;
import cn.hutool.core.map.MapUtil;
import org.junit.Assert;
import org.junit.Test;
import java.util.*;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import static java.util.Collections.singletonList;
@@ -62,17 +65,19 @@ public class FastStreamTest {
@Test
public void testToZip() {
List<Integer> orders = Arrays.asList(1, 2, 3);
List<String> list = Arrays.asList("dromara", "hutool", "sweet");
Map<Integer, String> toZip = FastStream.of(orders).toZip(list);
Assert.assertEquals(new HashMap<Integer, String>() {
private static final long serialVersionUID = 1L;
List<Integer> orders = Arrays.asList(1, 2, 3, 2);
List<String> list = Arrays.asList("dromara", "guava", "sweet", "hutool");
final Map<Integer, String> map = MapUtil.<Integer, String>builder()
.put(1, "dromara")
.put(2, "hutool")
.put(3, "sweet")
.build();
{
put(1, "dromara");
put(2, "hutool");
put(3, "sweet");
}}, toZip);
Map<Integer, String> toZip = FastStream.of(orders).toZip(list);
Assert.assertEquals(map, toZip);
Map<Integer, String> toZipParallel = FastStream.of(orders).parallel().toZip(list);
Assert.assertEquals(map, toZipParallel);
}
@Test
@@ -92,10 +97,10 @@ public class FastStreamTest {
private static final long serialVersionUID = 1L;
{
put("1", 1);
put("2", 2);
put("3", 3);
}}, identityMap);
put("1", 1);
put("2", 2);
put("3", 3);
}}, identityMap);
}
@Test
@@ -107,10 +112,10 @@ public class FastStreamTest {
private static final long serialVersionUID = 1L;
{
put("1", singletonList(1));
put("2", singletonList(2));
put("3", singletonList(3));
}}, group);
put("1", singletonList(1));
put("2", singletonList(2));
put("3", singletonList(3));
}}, group);
}
@Test
@@ -126,19 +131,29 @@ public class FastStreamTest {
public void testMapMulti() {
List<Integer> list = Arrays.asList(1, 2, 3);
List<Integer> mapMulti = FastStream.of(list).<Integer>mapMulti((e, buffer) -> {
if (e % 2 == 0) {
for (int i = 0; i < e; i++) {
buffer.accept(e);
}
buffer.accept(e);
}).toList();
Assert.assertEquals(Arrays.asList(1, 2, 2, 3), mapMulti);
Assert.assertEquals(Arrays.asList(1, 2, 2, 3, 3, 3), mapMulti);
}
@Test
public void testDistinct() {
List<Integer> list = Arrays.asList(1, 2, 2, 3);
List<Integer> distinctBy = FastStream.of(list).distinct(String::valueOf).toList();
Assert.assertEquals(Arrays.asList(1, 2, 3), distinctBy);
List<Integer> list = ListUtil.of(3, 2, 2, 1, null, null);
for (int i = 0; i < 1000; i++) {
list.add(i);
}
// 使用stream去重
List<Integer> collect1 = list.stream().distinct().collect(Collectors.toList());
List<Integer> collect2 = list.stream().parallel().distinct().collect(Collectors.toList());
// 使用FastStream去重
List<Integer> distinctBy1 = FastStream.of(list).distinct().toList();
List<Integer> distinctBy2 = FastStream.of(list).parallel().distinct(String::valueOf).toList();
Assert.assertEquals(collect1, distinctBy1);
Assert.assertEquals(collect2, distinctBy2);
}
@Test
@@ -165,7 +180,7 @@ public class FastStreamTest {
List<String> mapIndex = FastStream.of(list).flatMapIdx((e, i) -> FastStream.of(i + 1 + "." + e)).toList();
Assert.assertEquals(Arrays.asList("1.dromara", "2.hutool", "3.sweet"), mapIndex);
// 并行流时为-1
Assert.assertEquals(Arrays.asList(-1, -1, -1), FastStream.of(1, 2, 3).parallel().mapIdx((e, i) -> i).toList());
Assert.assertEquals(Arrays.asList(-1, -1, -1), FastStream.of(1, 2, 3).parallel().flatMapIdx((e, i) -> FastStream.of(i)).toList());
}
@Test
@@ -173,6 +188,9 @@ public class FastStreamTest {
List<Integer> list = Arrays.asList(1, 2, 3);
List<Integer> flatMapIter = FastStream.of(list).<Integer>flatMapIter(e -> null).toList();
Assert.assertEquals(Collections.emptyList(), flatMapIter);
flatMapIter = FastStream.of(list).flatMapIter(e -> Arrays.asList(e, e * 10)).toList();
Assert.assertEquals(ListUtil.of(1, 10, 2, 20, 3, 30), flatMapIter);
}
@Test
@@ -212,9 +230,9 @@ public class FastStreamTest {
}
@Test
public void testUnshift() {
public void testAddFirst() {
List<Integer> list = Arrays.asList(2, 3);
List<Integer> unshift = FastStream.of(list).unshift(1).toList();
List<Integer> unshift = FastStream.of(list).addFirst(1).toList();
Assert.assertEquals(Arrays.asList(1, 2, 3), unshift);
}
@@ -256,10 +274,10 @@ public class FastStreamTest {
@Test
public void testFindLast() {
List<Integer> list = Arrays.asList(1, null, 3);
Integer find = FastStream.of(list).findLast(Objects::nonNull);
List<Integer> list = ListUtil.of(1, null, 3);
Integer find = FastStream.of(list).parallel().findLast(Objects::nonNull);
Assert.assertEquals(3, (Object) find);
Assert.assertEquals(3, (Object) FastStream.of(list).findLast().orElse(null));
Assert.assertEquals(3, (Object) FastStream.of(list).parallel().findLast().orElse(null));
}
@Test
@@ -279,22 +297,24 @@ public class FastStreamTest {
}
@Test
public void testSub() {
public void testListSplit() {
List<Integer> list = Arrays.asList(1, 2, 3, 4, 5);
List<List<Integer>> lists = FastStream.of(list).sub(2).map(FastStream::toList).toList();
Assert.assertEquals(Arrays.asList(Arrays.asList(1, 2),
Arrays.asList(3, 4),
singletonList(5)
), lists);
List<List<Integer>> lists = FastStream.of(list).split(2).map(FastStream::toList).toList();
Assert.assertEquals(ListUtil.split(list, 2), lists);
// 指定长度 大于等于 列表长度
lists = FastStream.of(list).split(list.size()).map(FastStream::toList).toList();
Assert.assertEquals(singletonList(list), lists);
}
@Test
public void testSubList() {
public void testSplitList() {
List<Integer> list = Arrays.asList(1, 2, 3, 4, 5);
List<List<Integer>> lists = FastStream.of(list).subList(2).toList();
Assert.assertEquals(Arrays.asList(Arrays.asList(1, 2),
Arrays.asList(3, 4),
singletonList(5)
), lists);
List<List<Integer>> lists = FastStream.of(list).splitList(2).toList();
Assert.assertEquals(ListUtil.split(list, 2), lists);
// 指定长度 大于等于 列表长度
lists = FastStream.of(list).splitList(list.size()).toList();
Assert.assertEquals(singletonList(list), lists);
}
}