Java Core API

Not yet released

The Java API is not yet released. Estimated release: Q1 2027.

The Java library is a native port of TA-Lib in the com.tictactec.ta.lib package — no JNI, pure Java. Every indicator is a method on a Core instance, operates on double[] arrays, and is bit-identical to the C library over the same inputs.

To process a live feed one bar at a time instead of a whole array, see the companion Java Streaming API.

Calling a function

Each indicator takes a startIdx/endIdx range, the inputs, the optional parameters, two MInteger boxes reporting where the valid output begins and how many were written, and the caller-provided output array(s):

import com.tictactec.ta.lib.Core;
import com.tictactec.ta.lib.MInteger;
import com.tictactec.ta.lib.RetCode;

Core core = new Core();                 // create once, reuse

double[] close = /* ...your closing prices... */;
double[] out   = new double[close.length];
MInteger begIdx      = new MInteger();
MInteger nbElement   = new MInteger();

RetCode rc = core.sma(
    0, close.length - 1,   // startIdx, endIdx
    close,                 // input(s)
    30,                    // optInTimePeriod
    begIdx, nbElement,     // where valid output starts, how many are valid
    out);                  // output(s)

// out[0 .. nbElement.value - 1] holds the SMA; out[i] is input bar begIdx.value + i.
for (int i = 0; i < nbElement.value; i++) {
    System.out.println("bar " + (begIdx.value + i) + " = " + out[i]);
}

MInteger is a tiny mutable box (public int value) — the library's out-parameter idiom, since Java cannot return by reference.

Output size and lookback

An output is written only where the indicator is defined — a 30-period SMA has no value until the 30th bar. begIdx.value (outBegIdx) is the first valid bar and nbElement.value (outNBElement) is the count written; the rest of the array is left untouched. Size the output array to at least endIdx - startIdx + 1, or exactly with the lookback:

int lookback = core.smaLookback(30);    // 29 for a 30-period SMA

The lookback is how many inputs are consumed before the first output. If there is too little data to produce even one value, nbElement.value is 0.

Parameters and return codes

Integer parameters are int; real parameters are double; enumerated parameters use their enum type (e.g. MAType.Sma). Passing Integer.MIN_VALUE for an integer parameter (or the real-default sentinel -4e37 for a double parameter) selects that parameter's documented default.

Every method returns a RetCode: Success, BadParam, OutOfRangeStartIndex, OutOfRangeEndIndex, AllocErr, or InternalError.

float inputs

Every indicator is overloaded for float[] inputs as well as double[] — the float overload widens each element to double internally, so both produce identical output. Use it to feed price data already stored as float without copying.

Settings and threading

Library settings live on the Core instance:

core.SetUnstablePeriod(FuncUnstId.Ema, 10);
core.SetCompatibility(Compatibility.Metastock);
core.SetCandleSettings(/* ... */);

Do all such configuration once, from a single thread, before sharing the Core. After that, indicator calls on that instance are safe to make concurrently. To change a setting while streams or concurrent calls are live, use a separate Core instance.