Adding simple moving average (SMA).

We will add an indicator : simple moving average (SMA). Moving averages are one of the core indicators in technical analysis. It is simply the average price over the specified period.

 * Constructor.
public SimpleStrategy() {
    // Define series (we keep 100 bars).
    series = new BaseBarSeriesBuilder().withNumTypeOf(DoubleNum.class).withName("ETH/BTC").build();

    // Getting the simple moving average (SMA) of the close price over the last 5 ticks.
    ClosePriceIndicator closePrice = new ClosePriceIndicator(series);
    SMAIndicator shortSma = new SMAIndicator(closePrice, 5);
    SMAIndicator longSma = new SMAIndicator(closePrice, 30);

SMAs are often used to determine trend direction. If the SMA is moving up, the trend is up. If the SMA is moving down, the trend is down.