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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.
Wickra — C / C++
Streaming-first technical indicators for C and C++. A prebuilt shared/static
library plus a generated wickra.h — no system dependencies.
Wickra is a multi-language technical-analysis library with a Rust core and bindings for Python, Node.js and WebAssembly, plus a C ABI for C/C++, C#, Go, Java, R and any other C-capable language. Every indicator is an O(1) streaming state machine, so live trading bots and historical backtests share the exact same implementation. This package is the C ABI hub: it compiles the core to a C-compatible shared/static library plus a generated header, so any C-capable language (C, C++, Go, C#, Java, R) links against one artifact instead of re-wrapping every indicator natively.
Install
Grab the prebuilt header + library for your platform from the
GitHub releases — each archive
has wickra.h, the optional wickra.hpp C++ wrapper, and the shared/static
library — or build from source:
cargo build -p wickra-c --release
# -> target/release/libwickra.{so,dylib} or wickra.dll (+ import lib) + a staticlib
Then compile against the header and link the library
(cc app.c -I include -L lib -lwickra -lm -o app).
Quick start
#include "wickra.h"
struct Rsi *rsi = wickra_rsi_new(14); /* NULL on invalid params */
for (size_t i = 0; i < n; ++i) {
double v = wickra_rsi_update(rsi, prices[i]); /* NaN during warmup */
if (v == v && v > 70.0) /* v == v is the NaN check */
printf("overbought\n");
}
wickra_rsi_free(rsi); /* exactly once per _new */
Every indicator is an opaque handle with the same five functions —
_new / _update / _batch / _reset / _free. update is O(1); there is no
RAII across the C boundary, so each _new needs exactly one _free, and every
function is NULL-safe (a NULL handle yields NaN or a no-op, never a crash).
Multi-output indicators (MACD, Bollinger, ADX, …) take a pointer to a #[repr(C)]
struct and return a bool. The optional wickra.hpp wraps any handle in a
move-only wickra::Handle for exception-safe C++ lifetimes.
Documentation
The full indicator catalogue, guides, quickstarts, and API reference live in the main repository and documentation site:
- Repository & full indicator list: https://github.com/wickra-lib/wickra
- Docs (C quickstart, cookbook, TA-Lib migration): https://docs.wickra.org/Quickstart-C
- Runnable examples:
examples/c/
Wickra ships native bindings for Python, Node.js, WebAssembly and Rust, plus this C ABI hub that any C-capable language (C, C++, Go, C#, Java, R) links against — all exposing the same indicators from the shared Rust core.
Disclaimer
Wickra is an indicator toolkit, not a trading system. The values it computes are deterministic transforms of the input data — they are not financial advice and do not predict the market. Any use in a live trading context is at your own risk. The library is provided as is, without warranty of any kind.
License
Licensed under either of Apache-2.0 or MIT at your option.