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Class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;
    }
}

我有一个测试创建一个Hamcrest匹配器来匹配调用getClazz()的结果：

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，此匹配器在执行时抛出异常：

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)

有没有办法用LambdaJ编写这样的匹配器？

Answer 1

你不需要lambdaj来实现这一点。可以使用instanceOf matcher来执行此操作：

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