bug-fix: Initialize ThreadLocal static member variables on declaration (fixes 55).
#56
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WalkthroughThe changes in this pull request focus on the Changes
Sequence Diagram(s)sequenceDiagram
participant Thread as Thread
participant Factory as FlattenedByteArrayFactory
participant Stream as ByteArrayOutputStream
Thread->>Factory: Call fromStrings()
Factory->>Stream: reusableByteArrayOutputStream.get()
Stream-->>Factory: Return ByteArrayOutputStream instance
Factory->>Stream: Reset outputStream
Stream-->>Factory: OutputStream ready for use
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Actionable comments posted: 0
🧹 Outside diff range and nitpick comments (1)
src/main/java/com/yscope/clp/compressorfrontend/FlattenedByteArrayFactory.java (1)
50-51: Good simplification of ThreadLocal usage!The changes here effectively utilize the new ThreadLocal initialization. The code is now more straightforward and efficient:
- Direct use of
reusableByteArrayOutputStream.get()eliminates the need for null checks.- The
reset()call ensures a clean state for each use, preventing data interference between operations.This implementation aligns well with the ThreadLocal initialization, providing consistent and thread-safe usage.
A minor optimization suggestion:
Consider moving theoutputStreamvariable declaration inside the loop if it's not used outside the loop. This would slightly improve readability by keeping the variable closer to its usage.Here's a suggested minor refactor:
- ByteArrayOutputStream outputStream = reusableByteArrayOutputStream.get(); - outputStream.reset(); int[] elemEndOffsets = new int[strings.length]; for (int i = 0; i < strings.length; ++i) { + ByteArrayOutputStream outputStream = reusableByteArrayOutputStream.get(); + outputStream.reset(); byte[] bytes = strings[i].getBytes(StandardCharsets.UTF_8); outputStream.write(bytes, 0, bytes.length); elemEndOffsets[i] = outputStream.size(); }This change would reset the
outputStreamfor each iteration, which might be beneficial if the method is called with a large number of strings.
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- src/main/java/com/yscope/clp/compressorfrontend/FlattenedByteArrayFactory.java (2 hunks)
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🔇 Additional comments (2)
src/main/java/com/yscope/clp/compressorfrontend/FlattenedByteArrayFactory.java (2)
7-8: Excellent improvement in ThreadLocal initialization!The changes effectively address the issue mentioned in the PR objectives. By initializing the
reusableByteArrayOutputStreamas astatic finalThreadLocal withwithInitial, you ensure that:
- Each thread gets its own
ByteArrayOutputStreaminstance when first accessing the ThreadLocal.- The initialization happens at declaration time, preventing potential data races.
- The ThreadLocal itself is immutable, which is a good practice for thread safety.
This implementation is thread-safe and efficient, resolving the concurrency issues mentioned in issue #55.
Line range hint
1-63: Summary: Excellent resolution of ThreadLocal initialization and usage issuesThe changes in this file effectively address the concurrency issues mentioned in issue #55. The implementation of ThreadLocal for
reusableByteArrayOutputStreamis now thread-safe and efficient. Key improvements include:
- Proper initialization of ThreadLocal at declaration time.
- Simplified and consistent usage of ThreadLocal throughout the class.
- Elimination of potential data races.
These changes significantly improve the robustness and thread safety of the
FlattenedByteArrayFactoryclass. The code is now less prone to concurrency-related bugs and should perform more reliably in multi-threaded environments.Great job on implementing this fix!
References
#55
Description
We use
ThreadLocalto create a reusable per-thread data structure to flatten string arrays. However, this variable was initialized when it was first used, which introduced data race problems and caused failures in #55. This PR fixes the problem by initializing the per-thread data structure on the declaration.Validation performed
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