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Groups > comp.lang.java.programmer > #36856
| From | Jerry Stuckle <jstucklex@attglobal.net> |
|---|---|
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: How to assign an object to another in it method? |
| Date | 2017-07-11 21:46 -0400 |
| Organization | A noiseless patient Spider |
| Message-ID | <ok3ups$e2d$1@jstuckle.eternal-september.org> (permalink) |
| References | (13 earlier) <ojhgd6$bjn$1@gioia.aioe.org> <ojhi20$39m$1@jstuckle.eternal-september.org> <ojs006$1ls2$1@gioia.aioe.org> <ojs35k$hf4$1@jstuckle.eternal-september.org> <ok3ppi$j6k$1@gioia.aioe.org> |
On 7/11/2017 8:16 PM, Arne Vajhøj wrote: > On 7/8/2017 10:12 PM, Jerry Stuckle wrote: >> On 7/8/2017 9:13 PM, Arne Vajhøj wrote: >>> On 7/4/2017 10:18 PM, Jerry Stuckle wrote: >>>> On 7/4/2017 9:46 PM, Arne Vajhøj wrote: >>>>> On 7/3/2017 11:15 PM, Jerry Stuckle wrote: >>>>>> On 7/3/2017 10:04 PM, Arne Vajhøj wrote: >>>>>>> I hope that a static code analysis tool create warnings >>>>>>> about doing something like that. >>>>>> >>>>>> Why should they, Arne? Default values are just that - values used >>>>>> when >>>>>> no others are given. They are not the only valid values, and are >>>>>> there >>>>>> to be overridden. >>>>> >>>>> It indicates that the author of the super class and the author of the >>>>> sub class seems to disagree on at least one aspect of how the method >>>>> should be. That is something that should always be examined. Do the >>>>> classes really reflect an "is a" relation or is the difference a >>>>> symptom of a bigger difference/problem. >>> >>>> If that is the case, then the author of the superclass didn't design it >>>> properly. Default values are not there to indicate the only valid >>>> values for a class. They are there to allow for some (or all) >>>> values to >>>> be assumed. >>>> >>>> If there is a restriction in what the values can be, then that needs to >>>> be in the appropriate function. Otherwise, there is no restriction. >>> >>> Yes. But the topic was not valid values but default values. >> >> That is correct. And while the default values will be valid, if there >> are restrictions on non-default values those go in the function. >> >>>> If the subclass does not reflect an "is-a" relationship, that is a >>>> design problem which has nothing to do with default values. >>> >>> If it is the default values that break the "is a" then it has >>> something to do with it. >>> >> >> No, values don't break an is-a relationship. If the default values do, >> then you have an invalid relationship in the first place. > > It is rather simple English. > > Type X is feature set X with a default value of A. > > Type Y is a feature set of X + Y with a default value of B. > > Y "is a" X is false. > > Y "is almost a" X is true. > >>>> The bottom line here is - none of your arguments are related to the >>>> presence or absence of default arguments. All can occur either with or >>>> without default arguments. >>> >>> My argument relates specifically to different default values, so >>> it can not happen without default arguments. >> >> I stand by my statement. > > Given that the argument above very clearly relates to "default value" > then you are proven wrong. > >> Default values in a derived class which are >> not valid for the base class indicates an invalid relationship in the >> first place. > > Yes. But that is a straw man argument because my reasons do > not relate to valid values at all. > >> I would like to see an example of a valid relationship where your >> default values cause a problem. > > It is obvious that there is a problem with "is a". > > It could be totally harmless. > > Or it could be a good indication of a problem. > > It would be worth investigating what it is. > > Arne > > No, you said the default value for the derived class may be invalid for the base class. Therefore the inheritance would be invalid. It is a definite indication of a problem. In a valid hierarchy, derived classes are always more specialized cases of their base classes. In a case like this you can limit the wage in the derived class (Manager), but must stay within range of the base class (Employee). A value in Manager that is not valid in Employee indicates an invalid inheritance. -- ================== Remove the "x" from my email address Jerry Stuckle jstucklex@attglobal.net ==================
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How to assign an object to another in it method? parmenides <xparmenides@yahoo.com> - 2017-06-18 20:02 +0800
Re: How to assign an object to another in it method? Eric Sosman <esosman@comcast-dot-net.invalid> - 2017-06-18 08:09 -0400
Re: How to assign an object to another in it method? Robert Klemme <shortcutter@googlemail.com> - 2017-06-18 15:31 +0200
Re: How to assign an object to another in it method? Eric Sosman <esosman@comcast-dot-net.invalid> - 2017-06-19 10:22 -0400
Re: How to assign an object to another in it method? Eric Douglas <e.d.programmer@gmail.com> - 2017-06-19 08:13 -0700
Re: How to assign an object to another in it method? Eric Sosman <esosman@comcast-dot-net.invalid> - 2017-06-19 11:53 -0400
Re: How to assign an object to another in it method? Eric Douglas <e.d.programmer@gmail.com> - 2017-06-19 09:06 -0700
Re: How to assign an object to another in it method? Eric Sosman <esosman@comcast-dot-net.invalid> - 2017-06-19 13:56 -0400
Re: How to assign an object to another in it method? lewbloch@gmail.com - 2017-06-27 13:49 -0700
Re: How to assign an object to another in it method? Andreas Leitgeb <avl@logic.at> - 2017-06-28 12:20 +0000
Re: How to assign an object to another in it method? Eric Douglas <e.d.programmer@gmail.com> - 2017-06-28 05:51 -0700
Re: How to assign an object to another in it method? Eric Sosman <esosman@comcast-dot-net.invalid> - 2017-06-28 14:03 -0400
Re: How to assign an object to another in it method? Arne Vajhøj <arne@vajhoej.dk> - 2017-07-02 21:23 -0400
Re: How to assign an object to another in it method? Martin Gregorie <martin@address-in-sig.invalid> - 2017-07-03 10:59 +0000
Re: How to assign an object to another in it method? Arne Vajhøj <arne@vajhoej.dk> - 2017-07-03 08:38 -0400
Re: How to assign an object to another in it method? Andreas Leitgeb <avl@logic.at> - 2017-07-03 14:04 +0000
Re: How to assign an object to another in it method? Jerry Stuckle <jstucklex@attglobal.net> - 2017-07-03 10:39 -0400
Re: How to assign an object to another in it method? Andreas Leitgeb <avl@logic.at> - 2017-07-03 16:28 +0000
Re: How to assign an object to another in it method? Jerry Stuckle <jstucklex@attglobal.net> - 2017-07-03 16:52 -0400
Re: How to assign an object to another in it method? Arne Vajhøj <arne@vajhoej.dk> - 2017-07-03 22:04 -0400
Re: How to assign an object to another in it method? Jerry Stuckle <jstucklex@attglobal.net> - 2017-07-03 23:15 -0400
Re: How to assign an object to another in it method? Arne Vajhøj <arne@vajhoej.dk> - 2017-07-04 21:46 -0400
Re: How to assign an object to another in it method? Jerry Stuckle <jstucklex@attglobal.net> - 2017-07-04 22:18 -0400
Re: How to assign an object to another in it method? Arne Vajhøj <arne@vajhoej.dk> - 2017-07-08 21:13 -0400
Re: How to assign an object to another in it method? Jerry Stuckle <jstucklex@attglobal.net> - 2017-07-08 22:12 -0400
Re: How to assign an object to another in it method? Andreas Leitgeb <avl@logic.at> - 2017-07-11 17:56 +0000
Re: How to assign an object to another in it method? Jerry Stuckle <jstucklex@attglobal.net> - 2017-07-11 15:40 -0400
Re: How to assign an object to another in it method? Eric Douglas <e.d.programmer@gmail.com> - 2017-07-11 13:49 -0700
Re: How to assign an object to another in it method? Jerry Stuckle <jstucklex@attglobal.net> - 2017-07-11 17:41 -0400
Re: How to assign an object to another in it method? Arne Vajhøj <arne@vajhoej.dk> - 2017-07-11 20:27 -0400
Re: How to assign an object to another in it method? Jerry Stuckle <jstucklex@attglobal.net> - 2017-07-11 21:43 -0400
Re: How to assign an object to another in it method? Arne Vajhøj <arne@vajhoej.dk> - 2017-07-11 21:49 -0400
Re: How to assign an object to another in it method? Jerry Stuckle <jstucklex@attglobal.net> - 2017-07-12 17:20 -0400
Re: How to assign an object to another in it method? Andreas Leitgeb <avl@logic.at> - 2017-07-13 10:08 +0000
Re: How to assign an object to another in it method? Martin Gregorie <martin@address-in-sig.invalid> - 2017-07-13 11:35 +0000
Re: How to assign an object to another in it method? Arne Vajhøj <arne@vajhoej.dk> - 2017-07-13 08:14 -0400
Re: How to assign an object to another in it method? Martin Gregorie <martin@address-in-sig.invalid> - 2017-07-13 14:29 +0000
Re: How to assign an object to another in it method? Arne Vajhøj <arne@vajhoej.dk> - 2017-07-13 13:47 -0400
Re: How to assign an object to another in it method? Andreas Leitgeb <avl@logic.at> - 2017-07-13 18:09 +0000
Re: How to assign an object to another in it method? Arne Vajhøj <arne@vajhoej.dk> - 2017-07-13 15:01 -0400
Re: How to assign an object to another in it method? Andreas Leitgeb <avl@logic.at> - 2017-07-13 19:19 +0000
Re: How to assign an object to another in it method? Arne Vajhøj <arne@vajhoej.dk> - 2017-07-13 15:39 -0400
Re: How to assign an object to another in it method? Andreas Leitgeb <avl@logic.at> - 2017-07-13 16:49 +0000
Re: How to assign an object to another in it method? Jerry Stuckle <jstucklex@attglobal.net> - 2017-07-13 10:24 -0400
Re: How to assign an object to another in it method? Andreas Leitgeb <avl@logic.at> - 2017-07-13 17:19 +0000
Re: How to assign an object to another in it method? Arne Vajhøj <arne@vajhoej.dk> - 2017-07-13 21:17 -0400
Re: How to assign an object to another in it method? Andreas Leitgeb <avl@logic.at> - 2017-07-14 06:40 +0000
Re: How to assign an object to another in it method? Arne Vajhøj <arne@vajhoej.dk> - 2017-07-14 14:26 -0400
Re: How to assign an object to another in it method? Andreas Leitgeb <avl@logic.at> - 2017-07-15 14:36 +0000
Re: How to assign an object to another in it method? Jerry Stuckle <jstucklex@attglobal.net> - 2017-07-14 12:10 -0400
Re: How to assign an object to another in it method? Arne Vajhøj <arne@vajhoej.dk> - 2017-07-14 14:40 -0400
Re: How to assign an object to another in it method? Jerry Stuckle <jstucklex@attglobal.net> - 2017-07-14 14:51 -0400
Re: How to assign an object to another in it method? Arne Vajhøj <arne@vajhoej.dk> - 2017-07-14 21:05 -0400
Re: How to assign an object to another in it method? Arne Vajhøj <arne@vajhoej.dk> - 2017-07-14 21:06 -0400
Re: How to assign an object to another in it method? lewbloch@gmail.com - 2017-07-14 14:44 -0700
Re: How to assign an object to another in it method? Andreas Leitgeb <avl@logic.at> - 2017-07-12 16:23 +0000
Re: How to assign an object to another in it method? Eric Douglas <e.d.programmer@gmail.com> - 2017-07-12 10:12 -0700
Re: How to assign an object to another in it method? Arne Vajhøj <arne@vajhoej.dk> - 2017-07-11 20:16 -0400
Re: How to assign an object to another in it method? Jerry Stuckle <jstucklex@attglobal.net> - 2017-07-11 21:46 -0400
Re: How to assign an object to another in it method? Arne Vajhøj <arne@vajhoej.dk> - 2017-07-11 21:52 -0400
Re: How to assign an object to another in it method? Arne Vajhøj <arne@vajhoej.dk> - 2017-07-11 20:24 -0400
Re: How to assign an object to another in it method? Jerry Stuckle <jstucklex@attglobal.net> - 2017-07-11 21:49 -0400
Re: How to assign an object to another in it method? Arne Vajhøj <arne@vajhoej.dk> - 2017-07-11 21:55 -0400
Re: How to assign an object to another in it method? Martin Gregorie <martin@address-in-sig.invalid> - 2017-07-03 12:37 +0000
Re: How to assign an object to another in it method? Eric Sosman <esosman@comcast-dot-net.invalid> - 2017-07-03 11:34 -0400
Re: How to assign an object to another in it method? Martin Gregorie <martin@address-in-sig.invalid> - 2017-07-03 17:28 +0000
Re: How to assign an object to another in it method? v_borchert@despammed.com (Volker Borchert) - 2017-06-19 17:13 +0000
Re: How to assign an object to another in it method? Eric Douglas <e.d.programmer@gmail.com> - 2017-06-19 13:40 -0700
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