feat: Implement Fallback design pattern #2846#3538
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priyanshuvishwakarma273403 wants to merge 2 commits into
Open
feat: Implement Fallback design pattern #2846#3538priyanshuvishwakarma273403 wants to merge 2 commits into
priyanshuvishwakarma273403 wants to merge 2 commits into
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PR SummaryIntroduces a standalone Maven module Changes
autogenerated by presubmit.ai |
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✅ LGTM!
Review Summary
Commits Considered (2)
Files Processed (11)
- fallback/README.md (1 hunk)
- fallback/pom.xml (1 hunk)
- fallback/src/main/java/com/iluwatar/fallback/App.java (1 hunk)
- fallback/src/main/java/com/iluwatar/fallback/FallbackExecutor.java (1 hunk)
- fallback/src/main/java/com/iluwatar/fallback/FallbackService.java (1 hunk)
- fallback/src/main/java/com/iluwatar/fallback/PrimaryService.java (1 hunk)
- fallback/src/main/java/com/iluwatar/fallback/RemoteService.java (1 hunk)
- fallback/src/main/java/com/iluwatar/fallback/SimpleCircuitBreaker.java (1 hunk)
- fallback/src/test/java/com/iluwatar/fallback/AppTest.java (1 hunk)
- fallback/src/test/java/com/iluwatar/fallback/FallbackPatternTest.java (1 hunk)
- pom.xml (1 hunk)
Actionable Comments (0)
Skipped Comments (7)
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fallback/src/main/java/com/iluwatar/fallback/FallbackExecutor.java [46-46]
possible issue: "Handle potential null responses from primary service."
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fallback/src/main/java/com/iluwatar/fallback/FallbackExecutor.java [66-66]
behavior: "Circuit breaker fast-fail path."
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fallback/src/main/java/com/iluwatar/fallback/FallbackExecutor.java [81-81]
best-practice: "Timeout handling."
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fallback/src/main/java/com/iluwatar/fallback/FallbackExecutor.java [86-86]
best-practice: "Cancel task on timeout to free resources."
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fallback/src/main/java/com/iluwatar/fallback/FallbackExecutor.java [94-94]
maintainability: "Narrow exception handling in executor."
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fallback/src/main/java/com/iluwatar/fallback/SimpleCircuitBreaker.java [69-69]
design: "Circuit breaker state transitions."
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fallback/pom.xml [47-47]
best-practice: "Test dependencies: add junit-jupiter-api for API usage in tests."
Codecov Report❌ Patch coverage is Additional details and impacted files@@ Coverage Diff @@
## master #3538 +/- ##
============================================
+ Coverage 83.24% 83.27% +0.03%
- Complexity 4025 4050 +25
============================================
Files 1060 1065 +5
Lines 14246 14360 +114
Branches 686 690 +4
============================================
+ Hits 11859 11959 +100
- Misses 2100 2114 +14
Partials 287 287 ☔ View full report in Codecov by Harness. 🚀 New features to boost your workflow:
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What does this PR do?
This PR implements the Fallback design pattern as a standalone, self-contained Maven module (
fallback). The implementation demonstrates a robust resiliency mechanism commonly used in microservices architectures.Key Components Implemented:
RemoteService: A simple interface representing a service/dependency call that might fail.PrimaryService: ImplementsRemoteServiceto simulate the main dependency with configurable latency, timeout, and exceptions.FallbackService: ImplementsRemoteServiceand represents the fallback strategy, returning cached or degraded responses.SimpleCircuitBreaker: A thread-safe state machine (CLOSED, OPEN, HALF_OPEN) that monitors service health to fast-fail subsequent requests when the primary service is down.FallbackExecutor: Leverages Java 21's Virtual Threads to orchestrate the service call execution, applying timeouts and delegating to the fallback handler when failures, timeouts, or OPEN circuit states are encountered.App: Main application illustrating different runtime scenarios and state transitions (healthy call, exception, timeout, fast-failing during OPEN, and recovery back to CLOSED).Fixes #2846