| # Use annotation to mark the method you want to trace. |
| |
| * Add `@Trace` to any method you want to trace. After that, you can see the span in the Stack. |
| * Methods annotated with `@Tag` will try to tag the **current active span** with the given key (`Tag#key()`) and (`Tag#value()`), |
| if there is no active span at all, this annotation takes no effect. `@Tag` can be repeated, and can be used in companion with `@Trace`, see examples below. |
| The `value` of `Tag` is the same as what are supported in [Customize Enhance Trace](Customize-enhance-trace.md). |
| |
| ```java |
| /** |
| * The codes below will generate a span, |
| * and two types of tags, |
| one type tag: keys are `tag1` and `tag2`, values are the passed-in parameters, respectively, |
| the other type tag: keys are `username` and `age`, values are the return value in User, respectively |
| */ |
| @Trace |
| @Tag(key = "tag1", value = "arg[0]") |
| @Tag(key = "tag2", value = "arg[1]") |
| @Tag(key = "username", value = "returnedObj.username") |
| @Tag(key = "age", value = "returnedObj.age") |
| public User methodYouWantToTrace(String param1, String param2) { |
| // ... |
| } |
| ``` |
| _Sample codes only_ |
| |
