!27 CollectionUtils 新增distinct、convertMap 重载函数

Merge pull request !27 from 贺小五/feature/coll

!27 CollectionUtils 新增distinct、convertMap 重载函数
Merge pull request !27 from 贺小五/feature/coll
芋道源码 · Gitee
2 parents b8734fda fc3810e7
Showing 1 changed file with 49 additions and 6 deletions
src/main/java/cn/iocoder/dashboard/util/collection/CollectionUtils.java
@@ -4,8 +4,10 @@ import cn.hutool.core.collection.CollUtil;
 import cn.hutool.core.collection.CollectionUtil;
 import java.util.*;
+import java.util.function.BinaryOperator;
 import java.util.function.Function;
 import java.util.function.Predicate;
+import java.util.function.Supplier;
 import java.util.stream.Collectors;
 /**
@@ -30,6 +32,20 @@ public class CollectionUtils {
         return from.stream().filter(predicate).collect(Collectors.toList());
     }
+    public static <T, R> List<T> distinct(Collection<T> from, Function<T, R> keyMapper) {
+        if (CollUtil.isEmpty(from)) {
+            return new ArrayList<>();
+        }
+        return distinct(from, keyMapper, (t1, t2) -> t1);
+    }
+
+    public static <T, R> List<T> distinct(Collection<T> from, Function<T, R> keyMapper, BinaryOperator<T> cover) {
+        if (CollUtil.isEmpty(from)) {
+            return new ArrayList<>();
+        }
+        return new ArrayList<>(convertMap(from, keyMapper, Function.identity(), cover).values());
+    }
+
     public static <T, U> List<U> convertList(Collection<T> from, Function<T, U> func) {
         if (CollUtil.isEmpty(from)) {
             return new ArrayList<>();
@@ -48,30 +64,57 @@ public class CollectionUtils {
         if (CollUtil.isEmpty(from)) {
             return new HashMap<>();
         }
-        return from.stream().collect(Collectors.toMap(keyFunc, item -> item));
+        return convertMap(from, keyFunc, Function.identity());
+    }
+
+    public static <T, K> Map<K, T> convertMap(Collection<T> from, Function<T, K> keyFunc, Supplier<? extends Map<K, T>> supplier) {
+        if (CollUtil.isEmpty(from)) {
+            return supplier.get();
+        }
+        return convertMap(from, keyFunc, Function.identity(), supplier);
     }
     public static <T, K, V> Map<K, V> convertMap(Collection<T> from, Function<T, K> keyFunc, Function<T, V> valueFunc) {
         if (CollUtil.isEmpty(from)) {
             return new HashMap<>();
         }
-        return from.stream().collect(Collectors.toMap(keyFunc, valueFunc));
+        return convertMap(from, keyFunc, valueFunc, (v1, v2) -> v1);
+    }
+
+    public static <T, K, V> Map<K, V> convertMap(Collection<T> from, Function<T, K> keyFunc, Function<T, V> valueFunc, BinaryOperator<V> mergeFunction) {
+        if (CollUtil.isEmpty(from)) {
+            return new HashMap<>();
+        }
+        return convertMap(from, keyFunc, valueFunc, mergeFunction, HashMap::new);
+    }
+
+    public static <T, K, V> Map<K, V> convertMap(Collection<T> from, Function<T, K> keyFunc, Function<T, V> valueFunc, Supplier<? extends Map<K, V>> supplier) {
+        if (CollUtil.isEmpty(from)) {
+            return supplier.get();
+        }
+        return convertMap(from, keyFunc, valueFunc, (v1, v2) -> v1, supplier);
+    }
+
+    public static <T, K, V> Map<K, V> convertMap(Collection<T> from, Function<T, K> keyFunc, Function<T, V> valueFunc, BinaryOperator<V> mergeFunction, Supplier<? extends Map<K, V>> supplier) {
+        if (CollUtil.isEmpty(from)) {
+            return new HashMap<>();
+        }
+        return from.stream().collect(Collectors.toMap(keyFunc, valueFunc, mergeFunction, supplier));
     }
     public static <T, K> Map<K, List<T>> convertMultiMap(Collection<T> from, Function<T, K> keyFunc) {
         if (CollUtil.isEmpty(from)) {
             return new HashMap<>();
         }
-        return from.stream().collect(Collectors.groupingBy(keyFunc,
-                Collectors.mapping(t -> t, Collectors.toList())));
+        return from.stream().collect(Collectors.groupingBy(keyFunc, Collectors.mapping(t -> t, Collectors.toList())));
     }
     public static <T, K, V> Map<K, List<V>> convertMultiMap(Collection<T> from, Function<T, K> keyFunc, Function<T, V> valueFunc) {
         if (CollUtil.isEmpty(from)) {
             return new HashMap<>();
         }
-        return from.stream().collect(Collectors.groupingBy(keyFunc,
-                Collectors.mapping(valueFunc, Collectors.toList())));
+        return from.stream()
+                   .collect(Collectors.groupingBy(keyFunc, Collectors.mapping(valueFunc, Collectors.toList())));
     }
     // 暂时没想好名字，先以 2 结尾噶