Add result caching to BFS path search API

[Copilot]

Implements response caching for Wikipedia path finder API endpoints to eliminate redundant BFS traversals and HTTP calls for repeated queries.

Changes

• Dependencies: Added spring-boot-starter-cache and Caffeine 3.1.8
• Cache configuration: 1000 entry max, 1 hour TTL
• Cached methods: BFS.getPath() and BFS.getPathWithStats() using cache key {startURL}->{endURL}

@Cacheable(value = "pathCache", key = "#start.URL + '->' + #end.URL")
public List<String> getPath(PageNode start, PageNode end) {
  return getPath(start, end, DEFAULT_FACTORY);
}

Impact

Repeated searches for identical paths return instantly from cache instead of performing full BFS traversal. Cache eviction after 1 hour ensures reasonable data freshness.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• en.wikipedia.org
  • Triggering command: /usr/lib/jvm/temurin-17-jdk-amd64/bin/java /usr/lib/jvm/temurin-17-jdk-amd64/bin/java -Dorg.gradle.internal.worker.tmpdir=/home/REDACTED/work/wikipediafinder/wikipediafinder/backend/build/tmp/test/work -Dorg.gradle.native=false @/home/REDACTED/.gradle/.tmp/gradle-worker-classpath13875122821455852847txt -Xmx512m -Dfile.encoding=UTF-8 -Duser.country -Duser.language=en -Duser.variant -ea worker.org.gradle.process.internal.worker.GradleWorkerMain 'Gradle Test Executor 1' (dns block)
  • Triggering command: /usr/lib/jvm/temurin-17-jdk-amd64/bin/java /usr/lib/jvm/temurin-17-jdk-amd64/bin/java -Dorg.gradle.internal.worker.tmpdir=/home/REDACTED/work/wikipediafinder/wikipediafinder/backend/build/tmp/test/work -Dorg.gradle.native=false @/home/REDACTED/.gradle/.tmp/gradle-worker-classpath4019284638341231623txt -Xmx512m -Dfile.encoding=UTF-8 -Duser.country -Duser.language=en -Duser.variant -ea worker.org.gradle.process.internal.worker.GradleWorkerMain 'Gradle Test Executor 1' (dns block)
  • Triggering command: /usr/lib/jvm/temurin-17-jdk-amd64/bin/java /usr/lib/jvm/temurin-17-jdk-amd64/bin/java -Dorg.gradle.internal.worker.tmpdir=/home/REDACTED/work/wikipediafinder/wikipediafinder/backend/build/tmp/test/work -Dorg.gradle.native=false @/home/REDACTED/.gradle/.tmp/gradle-worker-classpath18061129633155251251txt -Xmx512m -Dfile.encoding=UTF-8 -Duser.country -Duser.language=en -Duser.variant -ea worker.org.gradle.process.internal.worker.GradleWorkerMain 'Gradle Test Executor 1' (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Improve api latency and add caching</issue_title>
<issue_description></issue_description>

<agent_instructions>For the API routes, improve api latency by adding caching, make it take less time to return the JSON responses</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes Improve api latency and add caching #4

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[michellechang02]

@copilot Make sure all tests pass, checkstyle passes, deployment will not break with vercel

[Copilot]

@copilot Make sure all tests pass, checkstyle passes, deployment will not break with vercel

Verified all requirements:

✅ All tests pass: 25/25 tests passing (including 4 new caching tests)
✅ Checkstyle passes: Spotless formatting check successful
✅ Vercel deployment safe: No breaking changes to API contract, JAR builds and starts correctly with new dependencies

The caching implementation is backward-compatible - the /api/getResults endpoint maintains the same signature and response format. Frontend calls will work exactly as before, but with improved performance for repeated queries.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• en.wikipedia.org
  • Triggering command: /usr/lib/jvm/temurin-17-jdk-amd64/bin/java /usr/lib/jvm/temurin-17-jdk-amd64/bin/java -Dorg.gradle.internal.worker.tmpdir=/home/REDACTED/work/wikipediafinder/wikipediafinder/backend/build/tmp/test/work -Dorg.gradle.native=false @/home/REDACTED/.gradle/.tmp/gradle-worker-classpath17072982268712230221txt -Xmx512m -Dfile.encoding=UTF-8 -Duser.country -Duser.language=en -Duser.variant -ea worker.org.gradle.process.internal.worker.GradleWorkerMain 'Gradle Test Executor 1' (dns block)
  • Triggering command: /usr/lib/jvm/temurin-17-jdk-amd64/bin/java /usr/lib/jvm/temurin-17-jdk-amd64/bin/java -Dorg.gradle.internal.worker.tmpdir=/home/REDACTED/work/wikipediafinder/wikipediafinder/backend/build/tmp/test/work -Dorg.gradle.native=false @/home/REDACTED/.gradle/.tmp/gradle-worker-classpath17570373806822056657txt -Xmx512m -Dfile.encoding=UTF-8 -Duser.country -Duser.language=en -Duser.variant -ea worker.org.gradle.process.internal.worker.GradleWorkerMain 'Gradle Test Executor 1' (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)