如何将ObjectProperty <bigdecimal>更改为DoubleBinding

Question

如何将ObjectProperty更改为DoubleBinding，然后放入Bindings.createObjectBinding（）;

private transient ObjectProperty<BigDecimal>  buy;
private transient ObjectProperty<BigDecimal>  sell;

有错误：

buy = Bindings.createObjectBinding(() -> (operation.get() == Operation.BUY) ? volume.get() : 0, volume, operation);

sell = Bindings.createDoubleBinding(() -> (operation.get() == Operation.SELL) ? volume.get() : 0, volume, operation);