NumberExpression is an
javafx.beans.value.ObservableNumberValue plus additional convenience
methods to generate bindings in a fluent style.
This API allows to mix types when defining arithmetic operations. The type of the result is defined by the same rules as in the Java Language.
To be able to deal with an unspecified return type, two interfaces
NumberExpression and its counterpart
javafx.beans.binding.NumberBinding were introduced. That means if the
return type is specified as
NumberBinding, the method will either
javafx.beans.binding.IntegerBinding, depending on the types of the
The API tries to do its best in determining the correct return type, e.g.
javafx.beans.value.ObservableNumberValue with a primitive
double will always result in a
cases where the return type is not known by the API, it is the responsibility
of the developer to call the correct getter (
intValue() etc.). If
the internal representation does not match the type of the getter, a standard
cast is done.