Market order is an order to buy or sell currency immediately at the best available market price. One can create a BUY and/or SELL market order by using a method IEngine.submitOrder).

Submit market order

Buy market order of 100'000 in EUR/USD:

IOrder order = engine.submitOrder("MyMaketBuyOrder", Instrument.EURUSD, OrderCommand.BUY, 0.1);

MarketOrder.java

Sell market order of 100'000 in EUR/USD:

IOrder order = engine.submitOrder("MyMarketSellOrder", Instrument.EURUSD, OrderCommand.SELL, 0.1);

Submit market order with slippage

In the two above methods the default slippage of 5 pips gets applied. It is also possible to specify a different slippage value by using the IEngine.submitOrder method with a price and slippage parameters. If zero price is used as parameter, then the latest market price will get used. Consider making a BUY market order of 100'000 in EUR/USD with slippage of 2 pips. double price = 0;

double price = 0;
int slippage = 2;
engine.submitOrder("OrderLabel", Instrument.EURUSD, OrderCommand.BUY, 0.1, price, slippage);

As soon as the market order is submitted order price will be equal to 0 and after the order is filled open price will be changed.