Скачать или смотреть Resolving retryWhen Issues After Migrating from rx-java to rx-java2

Discover how to fix the `retryWhen` hanging issue when migrating from rx-java to rx-java2, along with helpful code refactoring tips.
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This video is based on the question https://stackoverflow.com/q/77886117/ asked by the user 'Ben Green' ( https://stackoverflow.com/u/1987514/ ) and on the answer https://stackoverflow.com/a/77886729/ provided by the user 'Ben Green' ( https://stackoverflow.com/u/1987514/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Troubleshooting retryWhen Issues: Migrating from rx-java to rx-java2

Migrating code from one library version to another can often lead to unexpected issues. A common challenge faced during such transitions is adjusting to changes in how the library operates. In this post, we're addressing a particular problem that arises when migrating from rx-java to rx-java2. Specifically, this guide will cover how to resolve the hanging issue that occurs when using the retryWhen operator in your observable streams.

The Problem: Hanging Unit Tests After Migration

In your application, you previously handled retries for API calls gracefully using the retryWhen operator of rx-java. However, after migrating to rx-java2, you noticed that your unit tests hang indefinitely when the API responds with a ClientException that does not have a status code of 1 or 2.

This is the original method that was causing the issue:

[[See Video to Reveal this Text or Code Snippet]]

The Core Issue

The main problem stems from how error handling was structured. The original code filtered out errors but failed to maintain the proper flow of observables, leading to a case where non-retryable errors caused the observable stream to hang indefinitely.

The Solution: Refactoring the Code

To resolve the hanging issue, a bit of refactoring is necessary. Here’s the improved version of your methods:

[[See Video to Reveal this Text or Code Snippet]]

Explanation of the Changes

Reduction in Filtering:

Instead of filtering errors directly, we now use a method that decides whether the error is retryable or should be propagated upstream. This helps maintain the structure of the observable stream.

Centralized Error Handling:

The creation of the retryableOrError method consolidates the logic for determining whether to retry. If the exception is a ClientException with the acceptable status codes (1 or 2), it allows the retry, otherwise it returns the error.

Observable Range for Retries:

The use of zipWith allows us to track the number of retry attempts made without additional complexity.

Conclusion

By refactoring the way errors are handled in your observable stream, you can effectively resolve the hanging issue encountered after migrating from rx-java to rx-java2. This change not only enhances the readability of your code but also ensures that your unit tests run smoothly.

If you’re facing similar migration challenges or have found your own solutions, feel free to share your experiences in the comments!