diff --git a/hutool-core/src/main/java/cn/hutool/core/stream/EntryStream.java b/hutool-core/src/main/java/cn/hutool/core/stream/EntryStream.java
index d97e74a3f..81b7a6ecd 100644
--- a/hutool-core/src/main/java/cn/hutool/core/stream/EntryStream.java
+++ b/hutool-core/src/main/java/cn/hutool/core/stream/EntryStream.java
@@ -1,6 +1,7 @@
package cn.hutool.core.stream;
import cn.hutool.core.collection.ConcurrentHashSet;
+import cn.hutool.core.collection.iter.IterUtil;
import cn.hutool.core.map.multi.RowKeyTable;
import cn.hutool.core.map.multi.Table;
import cn.hutool.core.util.ObjUtil;
@@ -13,9 +14,9 @@ import java.util.stream.Stream;
import java.util.stream.StreamSupport;
/**
- * 针对键值对对象{@link Map.Entry}特化的增强流，
- * 本身可视为一个元素类型为{@link Map.Entry}的{@link Stream}。
- * 用于支持流式处理{@link Map}集合中的、或具有潜在可能转为{@link Map}集合的数据。
+ *
参考StreamEx的EntryStream与vavr的Map，是针对键值对对象{@link Map.Entry}特化的增强流实现。
+ * 本身可视为一个元素类型为{@link Map.Entry}的{@link Stream}，
+ * 用于支持流式处理{@link Map}集合中的、或其他键值对类型的数据。
*
* @param 键类型
* @param 值类型
@@ -23,6 +24,11 @@ import java.util.stream.StreamSupport;
*/
public class EntryStream extends StreamWrapper, EntryStream> {
+ /**
+ * 默认的空键值对
+ */
+ private static final Map.Entry EMPTY_ENTRY = new AbstractMap.SimpleImmutableEntry<>(null, null);
+
/**
* 根据键与值的集合创建键值对流，若两集合在相同下标的位置找不到对应的键或值，则使用{@code null}填充。
* 比如: {@code [1, 2, 3]}与{@code [1, 2]}合并，则得到{@code [{1=1}, {2=2}, {3=null}]}。
@@ -51,7 +57,7 @@ public class EntryStream extends StreamWrapper, EntryStrea
final Iterator keyItr = keys.iterator();
final Iterator valueItr = values.iterator();
while (keyItr.hasNext() || valueItr.hasNext()) {
- entries.add(new Entry<>(
+ entries.add(ofEntry(
keyItr.hasNext() ? keyItr.next() : null,
valueItr.hasNext() ? valueItr.next() : null
));
@@ -106,7 +112,7 @@ public class EntryStream extends StreamWrapper, EntryStrea
return empty();
}
final Stream> stream = StreamSupport.stream(source.spliterator(), false)
- .map(t -> new Entry<>(keyMapper.apply(t), valueMapper.apply(t)));
+ .map(t -> ofEntry(keyMapper.apply(t), valueMapper.apply(t)));
return new EntryStream<>(stream);
}
@@ -121,7 +127,7 @@ public class EntryStream extends StreamWrapper, EntryStrea
*/
public static EntryStream of(Stream> stream) {
return ObjUtil.isNull(stream) ?
- empty() : new EntryStream<>(stream.map(Entry::new));
+ empty() : new EntryStream<>(stream.map(EntryStream::ofEntry));
}
/**
@@ -142,19 +148,6 @@ public class EntryStream extends StreamWrapper, EntryStrea
super(stream);
}
- // ================================ override ================================
-
- /**
- * 根据一个原始的流，返回一个新包装类实例
- *
- * @param stream 流
- * @return 实现类
- */
- @Override
- protected EntryStream convertToStreamImpl(Stream> stream) {
- return new EntryStream<>(stream);
- }
-
// ================================ 中间操作 ================================
/**
@@ -164,7 +157,7 @@ public class EntryStream extends StreamWrapper, EntryStrea
*/
public EntryStream distinctByKey() {
Set accessed = new ConcurrentHashSet<>(16);
- return new EntryStream<>(stream.filter(e -> {
+ return convertToStreamImpl(stream.filter(e -> {
K key = e.getKey();
if (accessed.contains(key)) {
return false;
@@ -181,7 +174,7 @@ public class EntryStream extends StreamWrapper, EntryStrea
*/
public EntryStream distinctByValue() {
Set accessed = new ConcurrentHashSet<>(16);
- return new EntryStream<>(stream.filter(e -> {
+ return convertToStreamImpl(stream.filter(e -> {
V val = e.getValue();
if (accessed.contains(val)) {
return false;
@@ -229,6 +222,7 @@ public class EntryStream extends StreamWrapper, EntryStrea
*
* @return {@link EntryStream}实例
*/
+ @Override
public EntryStream nonNull() {
return super.filter(e -> ObjUtil.isNotNull(e) && ObjUtil.isNotNull(e.getKey()) && ObjUtil.isNotNull(e.getValue()));
}
@@ -304,8 +298,49 @@ public class EntryStream extends StreamWrapper, EntryStrea
* @param value 值
* @return {@link EntryStream}实例
*/
- public EntryStream push(K key, V value) {
- return new EntryStream<>(Stream.concat(stream, Stream.of(new Entry<>(key, value))));
+ public EntryStream append(K key, V value) {
+ return convertToStreamImpl(Stream.concat(stream, Stream.of(ofEntry(key, value))));
+ }
+
+ /**
+ * 项当前流队首追加元素
+ *
+ * @param key 键
+ * @param value 值
+ * @return {@link EntryStream}实例
+ */
+ public EntryStream prepend(K key, V value) {
+ return convertToStreamImpl(Stream.concat(Stream.of(ofEntry(key, value)), stream));
+ }
+
+ /**
+ * 将输入元素转为流，返回一个前半段为当前流，后半段为新流的新{@link EasyStream}实例
+ *
+ * @param entries 键值对
+ * @return {@link EntryStream}实例
+ */
+ public EntryStream append(Iterable> entries) {
+ if (IterUtil.isEmpty(entries)) {
+ return this;
+ }
+ final Stream> contacted = StreamSupport.stream(entries.spliterator(), isParallel())
+ .map(EntryStream::ofEntry);
+ return convertToStreamImpl(Stream.concat(stream, contacted));
+ }
+
+ /**
+ * 将输入元素转为流，返回一个前半段为新流，后半段为当前流的新{@link EasyStream}实例
+ *
+ * @param entries 键值对
+ * @return {@link EntryStream}实例
+ */
+ public EntryStream prepend(Iterable> entries) {
+ if (IterUtil.isEmpty(entries)) {
+ return this;
+ }
+ final Stream> contacted = StreamSupport.stream(entries.spliterator(), isParallel())
+ .map(EntryStream::ofEntry);
+ return convertToStreamImpl(Stream.concat(contacted, stream));
}
/**
@@ -336,7 +371,7 @@ public class EntryStream extends StreamWrapper, EntryStrea
public EntryStream mapKeys(Function mapper) {
Objects.requireNonNull(mapper);
return new EntryStream<>(
- stream.map(e -> new Entry<>(mapper.apply(e.getKey()), e.getValue()))
+ stream.map(e -> ofEntry(mapper.apply(e.getKey()), e.getValue()))
);
}
@@ -350,7 +385,7 @@ public class EntryStream extends StreamWrapper, EntryStrea
public EntryStream mapValues(Function mapper) {
Objects.requireNonNull(mapper);
return new EntryStream<>(
- stream.map(e -> new Entry<>(e.getKey(), mapper.apply(e.getValue())))
+ stream.map(e -> ofEntry(e.getKey(), mapper.apply(e.getValue())))
);
}
@@ -417,7 +452,7 @@ public class EntryStream extends StreamWrapper, EntryStrea
return new EntryStream<>(
stream.flatMap(e -> keyMapper
.apply(e.getKey())
- .map(newKey -> new Entry<>(newKey, e.getValue()))
+ .map(newKey -> ofEntry(newKey, e.getValue()))
)
);
}
@@ -441,7 +476,7 @@ public class EntryStream extends StreamWrapper, EntryStrea
return new EntryStream<>(
stream.flatMap(e -> valueMapper
.apply(e.getValue())
- .map(newVal -> new Entry<>(e.getKey(), newVal))
+ .map(newVal -> ofEntry(e.getKey(), newVal))
)
);
}
@@ -625,7 +660,7 @@ public class EntryStream extends StreamWrapper, EntryStrea
*/
public EntryStream inverse() {
return new EntryStream<>(
- stream.map(e -> new Entry<>(e.getValue(), e.getKey()))
+ stream.map(e -> ofEntry(e.getValue(), e.getKey()))
);
}
@@ -683,85 +718,34 @@ public class EntryStream extends StreamWrapper, EntryStrea
return super.noneMatch(e -> predicate.test(e.getKey(), e.getValue()));
}
+ // ========================= private =========================
+
/**
- * {@link Map.Entry}的基本实现
+ * 将键值对转为{@link AbstractMap.SimpleImmutableEntry}
*/
- static class Entry implements Map.Entry {
+ @SuppressWarnings("unchecked")
+ private static Map.Entry ofEntry(Map.Entry entry) {
+ return ObjUtil.defaultIfNull(
+ entry, e -> ofEntry(e.getKey(), e.getValue()), (Map.Entry)EMPTY_ENTRY
+ );
+ }
- /**
- * 键
- */
- private final K key;
-
- /**
- * 值
- */
- private V val;
-
- /**
- * 创建一个简单键值对对象
- *
- * @param key 键
- * @param val 值
- */
- public Entry(K key, V val) {
- this.key = key;
- this.val = val;
- }
-
- /**
- * 创建一个简单键值对对象
- *
- * @param entry 键值对
- */
- public Entry(Map.Entry entry) {
- if (ObjUtil.isNull(entry)) {
- this.key = null;
- this.val = null;
- } else {
- this.key = entry.getKey();
- this.val = entry.getValue();
- }
- }
-
- /**
- * 获取键
- *
- * @return 键
- */
- @Override
- public K getKey() {
- return key;
- }
-
- /**
- * 获取值
- *
- * @return 值
- */
- @Override
- public V getValue() {
- return val;
- }
-
- /**
- * 设置值
- *
- * @param value 值
- * @return 旧值
- */
- @Override
- public V setValue(V value) {
- V old = val;
- val = value;
- return old;
- }
-
- @Override
- public String toString() {
- return "{" + key + "=" + val + '}';
- }
+ /**
+ * 将键值对转为{@link AbstractMap.SimpleImmutableEntry}
+ */
+ private static Map.Entry ofEntry(K key, V value) {
+ return new AbstractMap.SimpleImmutableEntry<>(key, value);
+ }
+ /**
+ * 根据一个原始的流，返回一个新包装类实例
+ *
+ * @param stream 流
+ * @return 实现类
+ */
+ @Override
+ public EntryStream convertToStreamImpl(Stream> stream) {
+ return new EntryStream<>(stream);
}
/**
diff --git a/hutool-core/src/test/java/cn/hutool/core/stream/EntryStreamTest.java b/hutool-core/src/test/java/cn/hutool/core/stream/EntryStreamTest.java
index 3bbfe072c..c841d031f 100644
--- a/hutool-core/src/test/java/cn/hutool/core/stream/EntryStreamTest.java
+++ b/hutool-core/src/test/java/cn/hutool/core/stream/EntryStreamTest.java
@@ -116,8 +116,8 @@ public class EntryStreamTest {
Assert.assertEquals(
5,
EntryStream.of(Arrays.asList(1, 2, 3), Function.identity(), Function.identity())
- .push(4, 4)
- .push(5, 5)
+ .append(4, 4)
+ .append(5, 5)
.count()
);