Java 8 Stream.skip with Predicate [英] Java 8 Stream.skip with Predicate

问题描述

有没有办法做类似于Stream.skip（long）但使用Predicate而不是确切的数字？

Is there any way to do something similar to Stream.skip(long) but using Predicate instead of an exact number?

我需要跳过元素直到达到一个具有给定ID，然后我需要继续应用过滤器，限制等任何建议？

I need to skip elements until I reach one with a given ID and then I would need to continue applying filters, limit etc. Any suggestion?

推荐答案

编辑：更多简明版本是 https://stackoverflow.com/a/52270820/57695

A more concise version is https://stackoverflow.com/a/52270820/57695

我怀疑你需要编写一个有状态谓词或者使用一个包装器，如

I suspect you need to write a stateful predicate or use a wrapper like

public class FromPredicate<T> implements Predicate<T> {
    boolean started = false;
    Predicate<T> test;
    FromPredicate(Predicate<T> test) { this.test = test; }

    public static Predicate<T> from(Predicate<T> test) { return new FromPredicate<>(test); }

    public boolean test(T t) {
        return started || (started = test.test(t));
    }
}

在流中你可以这样做

Stream.of(1,2,3,4,5)
      .filter(from(i -> i % 2 == 0)))
      .forEach(System.out::println);

应打印

2
3
4
5

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