How do their APIs compare?

These two projects are fundamentally different in kind, so "API" means very different things in each. Here's the comparison:

baidu/uid-generator — a small, focused library API

It exposes a tiny, purpose-built contract meant to be wired via Spring:

• Core interface: UidGenerator has exactly two methods:

  • long getUID() throws UidGenerateException — get a unique ID
  • String parseUID(long uid) — decode a UID back into its timestamp/workerId/sequence components

• Two implementations of that interface, both configured as Spring beans rather than constructed with a fluent builder API:

  • DefaultUidGenerator [src/main/java/com/baidu/fsg/uid/impl/DefaultUidGenerator.java:L61-L100] — synchronous Snowflake-style generation, with setters like setTimeBits, setWorkerBits, setSeqBits, setEpochStr for bit-allocation customization, and a WorkerIdAssigner dependency for obtaining the worker id.
  • CachedUidGenerator [src/main/java/com/baidu/fsg/uid/impl/CachedUidGenerator.java:L51-L90] — extends DefaultUidGenerator, overrides getUID() to pull from an internal RingBuffer.take() instead of computing synchronously, and adds Spring-configurable properties (boostPower, paddingFactor, scheduleInterval, rejectedPutBufferHandler, rejectedTakeBufferHandler) plus lifecycle hooks afterPropertiesSet()/destroy() via Spring's InitializingBean/DisposableBean.

• Supporting SPI-style interfaces are small @FunctionalInterfaces meant for customization/injection, e.g. BufferedUidProvider.provide(long momentInSecond) [src/main/java/com/baidu/fsg/uid/buffer/BufferedUidProvider.java:L26-L36] and RejectedPutBufferHandler.rejectPutBuffer(...) [src/main/java/com/baidu/fsg/uid/buffer/RejectedPutBufferHandler.java:L25-L35].

• Typical caller usage is just uidGenerator.getUID() / uidGenerator.parseUID(uid), as shown in the test harness [src/test/java/com/baidu/fsg/uid/CachedUidGeneratorTest.java:L96-L100]. There is no REST/HTTP API — it's a library consumed in-process, configured via Spring XML bean definitions (README.md:L120-L182 walks through the defaultUidGenerator/cachedUidGenerator bean XML).

So uid-generator's "API" is deliberately minimal: 2 methods on the interface consumers actually call, plus a handful of Spring-injected setters/strategy interfaces for tuning internals (bit widths, epoch, ring buffer size, reject policies).

yuliskov/smarttube — an Android app's internal service/provider interfaces

Smarttube isn't a library with one canonical API; it's an Android app composed of many internal interfaces across features. Examples surfaced here:

• SearchTagsProvider [common/.../search/SearchTagsProvider.java:L7-L13] — a small callback-style interface: void search(String query, ResultsCallback callback), with an inner ResultsCallback.onResults(List<Tag>). Implementations include PrefsSearchTagsProvider [common/.../search/PrefsSearchTagsProvider.java:L8-L21] (static demo tags) and MediaServiceSearchTagProvider [common/.../search/MediaServiceSearchTagProvider.java:L13-L41] (RxJava-based, backed by a ContentService/YouTubeServiceManager).
• Third-party UI library interfaces bundled in the app, e.g. IDialog and IUser from the chatkit module [chatkit/.../commons/models/IDialog.java:L1-L24, chatkit/.../commons/models/IUser.java:L1-L21], and the MessageInput custom view [chatkit/.../messages/MessageInput.java:L1-L42].
• Larger st