Add the Java binding over the C ABI hub (Panama/FFM) (#233)

Adds a Java binding (`bindings/java`) over the C ABI hub — the fourth language stecker after C#, Go and R, reaching the hub through the Java Foreign Function & Memory API (Panama, `java.lang.foreign`, final in Java 22) rather than JNI or jextract. ## What's here - **`bindings/java`** — a Maven module (`org.wickra:wickra`) exposing all 514 indicators as idiomatic `AutoCloseable` classes. The downcall handles (`internal/NativeMethods.java`), the per-indicator wrappers and the output records are generated from `bindings/c/include/wickra.h` (same eight-archetype taxonomy as the C#/Go/R generators: scalar/batch, multi-output, bars, profile, values-profile, array-input). The opaque handle is a `MemorySegment` freed by a registered `java.lang.ref.Cleaner` action; multi-output returns a `record` (`null` at warmup), bars a `record[]`, profiles a record with a trailing `double[]`. The hand-written `WickraNative` resolves the native library (a bundled per-platform copy, or a `target/release` fallback for local development) and validates it against a sentinel symbol. repr(C) struct offsets are computed in the generator so the FFM reads land on the exact bytes. - **`examples/java`** — the full example suite mirroring C/C#/Go/R: streaming, backtest, multi_timeframe, parallel_assets (parallel streams), three strategies, and `FetchBtcusdt`/`LiveBinance`. - **CI** — a `java` job builds the C ABI library, sets up JDK 22 (Temurin, with a CDN-flake retry), runs the archetype test suite and the seven offline examples on Linux, macOS and Windows. - **Release** — a gated `java-publish` job (skipped until the `JAVA_PUBLISH_ENABLED` repository variable is set) stages the native libraries from the `wickra-c-<triple>.tar.gz` assets into the binding's resources and deploys to Maven Central with GPG signing. Independent of the GitHub-release job, like the NuGet job. - **Docs** — Java added to the README languages table, project layout, building/testing and comparison table, CONTRIBUTING, ARCHITECTURE, the examples index, the issue/PR templates, the About-description template, and the other binding READMEs. ## Requirements Java 22+ (the FFM API is final since Java 22). The binding requires `--enable-native-access=ALL-UNNAMED` at runtime; the test and example runners pass it automatically. No Rust crate or `Cargo.toml` change — the Java binding is standalone and additive. The generated `*.java` are committed (like the node `index.js`/`index.d.ts`); the generator stays private.
2026-06-09 20:30:29 +02:00
parent 8659b42bef
commit 167f7b3ffe
664 changed files with 44991 additions and 26 deletions
@@ -896,6 +896,77 @@ jobs:
      - name: Parse the network R examples
        run: Rscript -e 'invisible(lapply(c("examples/r/fetch_btcusdt.R", "examples/r/live_binance.R"), parse)); cat("network R examples parse OK\n")'

+  java:
+    name: Java on ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
+
+      - name: Install Rust toolchain
+        uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8 # stable branch, 2026-03-27
+
+      - name: Cache cargo
+        uses: Swatinem/rust-cache@e18b497796c12c097a38f9edb9d0641fb99eee32 # v2
+        continue-on-error: true # cache is an optimisation; never block on a stuck/slow restore
+        timeout-minutes: 6
+
+      # The binding links the C ABI hub at runtime through the Java FFM API; build
+      # it first so WickraNative's development fallback finds
+      # target/release/wickra.{so,dylib,dll}. JDK 22+ is required for the final FFM
+      # API, so it is installed explicitly (runners ship 17/21).
+      - name: Build the C ABI library
+        run: cargo build -p wickra-c --release
+
+      - name: Set up JDK 22
+        id: setup-java
+        continue-on-error: true
+        uses: actions/setup-java@c1e323688fd81a25caa38c78aa6df2d33d3e20d9 # v4
+        with:
+          distribution: temurin
+          java-version: "22"
+          cache: maven
+
+      - name: Retry JDK setup (CDN flake)
+        if: steps.setup-java.outcome == 'failure'
+        shell: bash
+        run: |
+          echo "::warning::setup-java failed (likely CDN flake), waiting 30s before retry..."
+          sleep 30
+
+      - name: Set up JDK 22 (retry)
+        if: steps.setup-java.outcome == 'failure'
+        uses: actions/setup-java@c1e323688fd81a25caa38c78aa6df2d33d3e20d9 # v4
+        with:
+          distribution: temurin
+          java-version: "22"
+          cache: maven
+
+      - name: Java info
+        run: java -version
+
+      # `install` runs the archetype test suite (the real FFI boundary check) and
+      # installs the binding to the local repo so the examples can resolve it.
+      - name: Test and install the Java binding
+        run: mvn -B -f bindings/java install
+
+      - name: Build the Java examples
+        run: mvn -B -f examples/java compile
+
+      # Run only the offline examples (fetch_btcusdt / live_binance need network).
+      - name: Run the offline Java examples
+        shell: bash
+        run: |
+          for cls in Streaming Backtest MultiTimeframe ParallelAssets \
+                     StrategyRsiMeanReversion StrategyMacdAdx StrategyBollingerSqueeze; do
+            mvn -B -q -f examples/java exec:exec -Dexec.mainClass="org.wickra.examples.$cls"
+          done
+
  # The cross-library benchmark has moved to a dedicated scheduled workflow
  # (.github/workflows/bench.yml) — see audit finding R10. It runs nightly
  # at 03:00 UTC and on-demand via `workflow_dispatch`, and is no longer on