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添加工具类

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lihongjie0209
2023-09-10 20:24:41 +08:00
parent 3aa306c72f
commit 741fc2e6bd
1 changed files with 80 additions and 0 deletions
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src/main/java/cn/lihongjie/coal/common/CollectionUtils.java Normal file
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package cn.lihongjie.coal.common;
import io.vavr.Tuple2;
import lombok.experimental.UtilityClass;
import org.apache.commons.lang3.ObjectUtils;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.function.BiFunction;
import java.util.function.Function;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;
@UtilityClass
public class CollectionUtils {
public static <Data, T> List<T> map(Iterable<Data> data, Function<Data, T> fn) {
return StreamSupport.stream(data.spliterator(), false).map(fn).collect(java.util.stream.Collectors.toList());
}
public static <A, B, K> List<Tuple2<A, B>> innerHashJoin(Iterable<A> a, Iterable<B> b, Function<A, K> ak, Function<B, K> bk) {
Map<K, List<A>> aMap = newStream(a).collect(Collectors.groupingBy(ak));
Map<K, List<B>> bMap = newStream(b).collect(Collectors.groupingBy(bk));
return aMap.keySet().stream().flatMap(k -> aMap.getOrDefault(k, new ArrayList<>()).stream().flatMap(av -> bMap.getOrDefault(k, new ArrayList<>()).stream().map(bv -> new Tuple2<>(av, bv)))).collect(java.util.stream.Collectors.toList());
}
public static <A, B> List<Tuple2<A, B>> innerNestJoin(Iterable<A> a, Iterable<B> b, BiFunction<A, B, Boolean> test) {
a = ObjectUtils.defaultIfNull(a, new ArrayList<>());
b = ObjectUtils.defaultIfNull(b, new ArrayList<>());
List<Tuple2<A, B>> ans = new ArrayList<>();
for (A a1 : a) {
for (B b1 : b) {
if (test.apply(a1, b1)) {
ans.add(new Tuple2<>(a1, b1));
}
}
}
return ans;
}
public static <A, B, K> List<Tuple2<A, B>> leftHashJoin(Iterable<A> a, Iterable<B> b, Function<A, K> ak, Function<B, K> bk) {
Map<K, List<A>> aMap = newStream(a).collect(Collectors.groupingBy(ak));
Map<K, List<B>> bMap = newStream(b).collect(Collectors.groupingBy(bk));
return aMap.keySet().stream().flatMap(k -> aMap.getOrDefault(k, new ArrayList<>()).stream().flatMap(av -> bMap.getOrDefault(k, List.of((B) null)).stream().map(bv -> new Tuple2<>(av, bv)))).collect(java.util.stream.Collectors.toList());
}
public static <A, B> List<Tuple2<A, B>> leftNestJoin(Iterable<A> a, Iterable<B> b, BiFunction<A, B, Boolean> test) {
a = ObjectUtils.defaultIfNull(a, new ArrayList<>());
b = ObjectUtils.defaultIfNull(b, new ArrayList<>());
List<Tuple2<A, B>> ans = new ArrayList<>();
for (A a1 : a) {
boolean find = false;
for (B b1 : b) {
if (test.apply(a1, b1)) {
ans.add(new Tuple2<>(a1, b1));
find = true;
}
}
if (!find) {
ans.add(new Tuple2<>(a1, null));
}
}
return ans;
}
private static <A> Stream<A> newStream(Iterable<A> a) {
return StreamSupport.stream(a == null ? new ArrayList<A>().spliterator() : a.spliterator(), false);
}
}