java - LambdaJ 类属性匹配器

Question

我正在尝试编写一个 Hamcrest 匹配器来验证返回类对象的方法的返回值。例如，给定类:

public static class ClassHolder {
    private final Class clazz;

    public ClassHolder(Class clazz) {
        this.clazz = clazz;
    }

    public Class getClazz() {
        return clazz;
    }
}

我有一个创建 Hamcrest 匹配器以匹配调用 getClazz() 的结果的测试:

public class LambdaJTest {
    @Test
    public void testClassHolder() {
        final ClassHolder classHolder = new ClassHolder(String.class);
        assertThat(classHolder, having(on(ClassHolder.class).getClazz(), is(String.class)));
    }
}

但是，这个匹配器在执行时会抛出异常:

ch.lambdaj.function.argument.ArgumentConversionException: It is not possible to create a placeholder for class: java.lang.Class
    at ch.lambdaj.function.argument.ArgumentsFactory.createArgumentPlaceholder(ArgumentsFactory.java:170)
    at ch.lambdaj.function.argument.ArgumentsFactory.createArgumentPlaceholder(ArgumentsFactory.java:156)
    at ch.lambdaj.function.argument.ArgumentsFactory.createPlaceholder(ArgumentsFactory.java:52)
    at ch.lambdaj.function.argument.ArgumentsFactory.registerNewArgument(ArgumentsFactory.java:45)
    at ch.lambdaj.function.argument.ArgumentsFactory.createArgument(ArgumentsFactory.java:39)
    at ch.lambdaj.function.argument.ProxyArgument.invoke(ProxyArgument.java:36)
    at ch.lambdaj.proxy.InvocationInterceptor.intercept(InvocationInterceptor.java:42)

有没有办法使用 LambdaJ 编写这样的匹配器？

Answer 1

您不需要 lambdaj 来实现它。可以使用 instanceOf matcher 来做到这一点如下所示:

assertThat(classHolder.getClazz(), Matchers.instanceOf(String.class)));