Java 不具有 equals 和 hashCode 的类型的集合

我必须使用第三方库中没有equals和hashCode的类型.

在我的示例中，这将由包含一些数据的类Box播放.

问题是，我的实现仍然没有考虑到唯一实例的基数.

import org.junit.jupiter.api.Test;

import java.util.Collection;
import java.util.Objects;
import java.util.function.BiPredicate;

import static org.assertj.core.util.Lists.newArrayList;
import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertTrue;

class CustomEqualsTest {

    public static final BiPredicate<Box, Box> EQUALS = CustomEqualsTest::equals;

    static boolean equals(Box b1, Box b2) {
        if (b1 == b2) {
            return true;
        }
        if (b1 != null && b2 != null) {
            return Objects.equals(b1.data, b2.data);
        }
        return false;
    }

    static class Box {
        Integer data;

        private Box(Integer data) {
            this.data = data;
        }

        static Box of(Integer data) {
            return new Box(data);
        }
        // intentionally skip equals
        // intentionally skip hashCode
    }

    @Test
    void testCustomEquals() {
        assertTrue(equals(
                newArrayList(Box.of(1)),
                newArrayList(Box.of(1)), EQUALS));
        assertFalse(equals(
                newArrayList(Box.of(1)),
                newArrayList(), EQUALS));
        assertFalse(equals(
                newArrayList(Box.of(1)),
                newArrayList((Box) null), EQUALS));
        assertFalse(equals(
                newArrayList(Box.of(1)),
                newArrayList(Box.of(2)), EQUALS));
        assertFalse(equals(
                newArrayList(Box.of(1), Box.of(1)),
                newArrayList(Box.of(1)), EQUALS));

        // This fails:
        assertFalse(
                equals(
                        newArrayList(Box.of(1), Box.of(1), Box.of(2)),
                        newArrayList(Box.of(1), Box.of(2), Box.of(2)),
                        EQUALS));

    }

    static <T> boolean equals(Collection<T> collection1, Collection<T> collection2, BiPredicate<T, T> equals) {
        if (collection1.size() != collection2.size()) {
            return false;
        }

        for (T t1 : collection1) {
            boolean match = false;
            for (T t2 : collection2) {
                if (equals.test(t1, t2)) {
                    match = true;
                    break;
                }
            }
            if (!match) {
                return false;
            }
        }
        return true;
    }

}