@Override
    public final String getNotSetMessage() {
        if (!anon) {
            return "The parameter " + name + " needs to be set";
        } else {
            return "A parameter of type " + getType().getName() + " was not set";
        }
    }
{@code ParamExpressionImpl} defines a parameter in a query with an optional name

@author tiwe

@param <T> expression type
querydsl-core/src/main/java/com/querydsl/core/types/ParamExpressionImpl.java