没有警告的通用接口比较器

发布于 2024-09-30 00:11:44 字数 417 浏览 0 评论 0原文

鉴于：

public interface PrimaryKey<Key extends Comparable> {
    Key getKey();
}

和

public class PrimaryKeyComparator implements Comparator<PrimaryKey> {
    public int compare(PrimaryKey first, PrimaryKey second) {
        return first.getKey().compareTo(second.getKey());
    }
}

此组合有效，但会给出有关原始类型的警告。我尝试了各种添加类型参数的方法，但我尝试的每种组合都会破坏代码。

原文

Given:

public interface PrimaryKey<Key extends Comparable> {
    Key getKey();
}

and

public class PrimaryKeyComparator implements Comparator<PrimaryKey> {
    public int compare(PrimaryKey first, PrimaryKey second) {
        return first.getKey().compareTo(second.getKey());
    }
}

This combination works, but gives warnings about raw types. I've tried various ways of adding the type arguments, but every combination I've tried breaks the code.

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忆依然 2024-10-07 00:11:44

试试这个：

public interface PrimaryKey<TKey extends Comparable<TKey>> {
    TKey getId();
}

public class PrimaryKeyComparator<TKey extends Comparable<TKey>> 
                                 implements Comparator<PrimaryKey<TKey>> {
    public int compare(PrimaryKey<TKey> first, PrimaryKey<TKey> second) {
        return first.getId().compareTo(second.getId());
    }
}

Try this:

public interface PrimaryKey<TKey extends Comparable<TKey>> {
    TKey getId();
}

public class PrimaryKeyComparator<TKey extends Comparable<TKey>> 
                                 implements Comparator<PrimaryKey<TKey>> {
    public int compare(PrimaryKey<TKey> first, PrimaryKey<TKey> second) {
        return first.getId().compareTo(second.getId());
    }
}

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