闭包意味着完全类型安全的标准？

发布于 2024-08-12 11:00:11 字数 606 浏览 5 评论 0原文

结合闭包（FCM）和泛型，是否有可能拥有完全类型安全的标准。

// The following works without a cast as Foo.id is a 'long' field.
List<Long> ids = session.createCriteria(Foo.class)
                        .setProjection(Foo#id)
                        .list();

// The following is a compilation error, as Foo.bar is defined as an int, and not a string
session.createCriteria(Foo.class)
       .addRestriction(Restrictions.eq(Foo#bar,"blah"))
       .list();

我已阅读 JPA 2.0 规范以了解类型安全标准。但还是有些欠缺。

此外，我只是在这里使用标准作为总体上改进代码类型安全性的示例。我大量使用 java 的静态类型来让我编码得更快。但结果是我时不时地被代码中忽略输入的部分所困扰。例如 HQL 查询。

原文

combining closures (FCM) and generics, would it be possible to have fully type-safe criteria.

// The following works without a cast as Foo.id is a 'long' field.
List<Long> ids = session.createCriteria(Foo.class)
                        .setProjection(Foo#id)
                        .list();

// The following is a compilation error, as Foo.bar is defined as an int, and not a string
session.createCriteria(Foo.class)
       .addRestriction(Restrictions.eq(Foo#bar,"blah"))
       .list();

I've read the JPA 2.0 spec for type-safe criteria. But its still somewhat lacking.

Besides, I'm just using criteria here as an example of improving the type-safety of code in general. I used the static typing of java heavily to let me code faster. But as a result I get bitten now and then by the parts of my code that ignore typing. For example HQL queries.

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