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Groups > comp.lang.java.help > #653

Re: Why can one invoke setters and getters from a (class) constructor?

From Lew <noone@lewscanon.com>
Newsgroups comp.lang.java.help
Subject Re: Why can one invoke setters and getters from a (class) constructor?
Date 2011-04-25 15:14 -0400
Organization albasani.net
Message-ID <ip4h5p$v3n$1@news.albasani.net> (permalink)
References <87bozwkgz8.fsf@merciadriluca-station.MERCIADRILUCA> <0na8r6tg38fu60ojepfl5h4u20lmhfhffr@4ax.com> <fd44b4d4-872d-442c-93d3-a80761ac19ae@w9g2000prg.googlegroups.com>

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Fred wrote:
> However, it can be dangerous for a constructor to call any method that
> a subclass might override, because the superclass constructor would
> then invoke the subclass method BEFORE the subclass constructor has
> been called, and the subclass method may try to operate on subclass
> variables that have not yet been created.
>
> Examples: Swing's JComponent constructor calls setBackground() and
> setFont(). But if your component that is a subclass of JComponent is a
> container that creates many other subcomponents, you might want your
> setBackground() method to change the backgrounds of itself and all of
> its subcomponents. But the JComponent constructor will invoke your
> setBackground() before your constructor has created any of those
> subcomponents.
>
> When I write constructors, they NEVER call any method that is not
> private.

or 'final'

-- 
Lew
Honi soit qui mal y pense.
http://upload.wikimedia.org/wikipedia/commons/c/cf/Friz.jpg

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Why can one invoke setters and getters from a (class) constructor? Merciadri Luca <Luca.Merciadri@student.ulg.ac.be> - 2011-04-23 19:36 +0200
  Re: Why can one invoke setters and getters from a (class) constructor? Lew <noone@lewscanon.com> - 2011-04-23 13:58 -0400
  Re: Why can one invoke setters and getters from a (class) constructor? markspace <-@.> - 2011-04-23 11:00 -0700
    Re: Why can one invoke setters and getters from a (class) constructor? Merciadri Luca <Luca.Merciadri@student.ulg.ac.be> - 2011-04-23 23:53 +0200
  Re: Why can one invoke setters and getters from a (class) constructor? Joshua Cranmer <Pidgeot18@verizon.invalid> - 2011-04-23 20:36 -0400
    Re: Why can one invoke setters and getters from a (class) constructor? Lew <noone@lewscanon.com> - 2011-04-23 22:37 -0400
  Re: Why can one invoke setters and getters from a (class) constructor? Roedy Green <see_website@mindprod.com.invalid> - 2011-04-24 06:53 -0700
    Re: Why can one invoke setters and getters from a (class) constructor? Fred <fred.l.kleinschmidt@boeing.com> - 2011-04-25 11:06 -0700
      Re: Why can one invoke setters and getters from a (class) constructor? Lew <noone@lewscanon.com> - 2011-04-25 15:14 -0400

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