Java函数式接口在单元测试和代码重用中的应用场景

@Test
public void testServiceWithMockDependency() {
    Service service = new Service();
    // 创建一个 Mock 对象来模拟依赖项
    MyDependency mockDependency = mock(MyDependency.class);
    // 设置 mock 对象的预期行为
    when(mockDependency.getValue()).thenReturn("mocked value");

    // 将 mock 对象注入 service 中
    service.setDependency(mockDependency);

    // 验证 service 的行为
    assertEquals("mocked value", service.getResult());
}

@Test
public void testServiceWithLambdaAssert() {
    Service service = new Service();

    // 使用 Lambda 表达式定义自定义断言
    Assert.assertThat(service.getResult(), is(equalTo("expected value")));
}

// 定义策略接口
@FunctionalInterface
public interface MyStrategy {
    void execute();
}

public class Client {

    public void process(MyStrategy strategy) {
        strategy.execute();
    }
}

// 不同策略的实现
class StrategyA implements MyStrategy {
    @Override
    public void execute() {
        // ...
    }
}

class StrategyB implements MyStrategy {
    @Override
    public void execute() {
        // ...
    }
}

// 定义回调接口
@FunctionalInterface
public interface MyCallback {
    void callback(String message);
}

public class Client {

    public void process(MyCallback callback) {
        // ...
        callback.callback("message");
    }
}

// 回调函数的实现
class MyCallbackImpl implements MyCallback {
    @Override
    public void callback(String message) {
        // ...
    }
}