Java Streaming API

Not yet released

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

The batch methods (core.sma, core.rsi, …) recompute over a whole array. The streaming API returns a small handle that carries state between bars, so each new bar costs O(1) — and every value is bit-identical to the batch method over the same series. Ideal for live feeds.

Each streamable function adds two factory methods on Core and a handful of methods on its handle (a class nested in Core, e.g. Core.SmaStream — unrelated to java.util.stream):

Call	When	Does
core.<name>Open(history, params)	once	validate params, consume warm-up history, return a handle
core.<name>OpenAndFill(..)	once, instead of Open	like Open, but also fills the output for every history bar — see below
handle.update(bar)	once per closed bar	commit one bar, return the new value
handle.peek(bar)	any time on the forming bar	evaluate a provisional bar without committing
handle.value()	any time	the most recently committed value
handle.copy()	any time	an independent copy of the stream

There is no close — a handle is ordinary heap state, so an unreferenced handle is simply garbage-collected.

Example (SMA)

import com.tictactec.ta.lib.Core;

Core core = new Core();

// Seed with warm-up history (>= smaLookback(period) + 1 bars).
double[] history = /* ...your closing prices... */;
Core.SmaStream s = core.smaOpen(history, 30);   // value() starts at the last history bar

// Each time a bar closes:
double v = s.update(newClose);                  // always a value; never throws after open

// Intra-bar, on the not-yet-closed bar (repeat as the price ticks):
double provisional = s.peek(formingClose);      // state left unchanged

Open returns the handle directly; its value() starts at the last history bar's value. After a successful Open, update and peek never throw.

Rules

• Warm-up. Open succeeds only if history.length >= <name>Lookback(params) + 1 — with fewer bars there is no defined value yet. Too little history throws InsufficientHistoryException (see Error model). After Open, the history can be discarded — the handle keeps everything it needs.
• Closed vs forming bar. update commits state irreversibly, so use it only for closed bars. peek returns exactly the value the next update would, without committing; it runs the same code on a throwaway deep copy (which allocates for windowed indicators — update is the cheaper path). value() re-reads the last committed value without recomputing.
• Parameters are fixed at Open. Changing a parameter means a new stream. Unstable period, compatibility, and candle settings are captured at Open and must not change on the owning Core while its streams are live.
• Threads. A handle is single-writer — update, peek, value(), and copy() must not race with an update on the same handle. With no concurrent update, peek/value()/copy() are read-only and safe to call concurrently after safe publication. Independent handles (including copy() results) are fully independent.
• Not serializable. To checkpoint, retain the history and re-open — the result is bit-identical by contract.

Full-history output (OpenAndFill)

Open gives you only the value at the last history bar. OpenAndFill also writes the output for every history bar — the same values the batch method would produce — while still returning the live handle, in one pass:

MInteger beg = new MInteger(), nb = new MInteger();
double[] warmup = new double[history.length];

Core.SmaStream s = core.smaOpenAndFill(history, 30, beg, nb, warmup);

// warmup[0 .. nb.value - 1] is the SMA over all of history; then stream on:
double v = s.update(newClose);

The optional parameters and outputs (outBegIdx, outNBElement, one array per output) are exactly the batch method's; the output arrays must not alias the input or each other.

Multi-input / multi-output

Inputs and outputs mirror the batch method. Multi-output functions return a small immutable Value class with one final field per output, in batch output order; candlestick patterns return int:

// MACD: one input, three outputs
Core.MacdStream m = core.macdOpen(history, 12, 26, 9);
Core.MacdStream.Value out = m.update(newClose);
// out.macd, out.macdSignal, out.macdHist

// A candlestick pattern returns int
Core.CdlDojiStream c = core.cdlDojiOpen(open, high, low, close);
int pattern = c.update(o, h, l, cl);

Error model

Call	Behaviour
<name>Open / <name>OpenAndFill	Too little history throws InsufficientHistoryException (a subclass of IllegalArgumentException — catch it to accumulate more bars and retry). Out-of-range parameters, or output arrays that alias the input or each other (OpenAndFill), throw plain IllegalArgumentException.
update / peek / value / copy	Never throw after a successful Open.

Discovering streamable functions

When driving TA-Lib through the abstraction layer, streamable functions carry the TA_FUNC_FLG_STREAM flag in their function info.