Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!feeder.erje.net!eu.feeder.erje.net!eternal-september.org!feeder.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: Jim Janney <jjanney@shell.xmission.com>
Newsgroups: comp.lang.java.programmer
Subject: Re: unnecessary code in Oracle example?
Date: Wed, 09 Oct 2013 14:21:07 -0600
Organization: use only as directed
Lines: 73
Message-ID: <ydna9iijivg.fsf@shell.xmission.com>
References: <ydnr4bujt72.fsf@shell.xmission.com> <u6h5u.69447$yx6.64233@fx26.iad> <ydneh7ujm7q.fsf@shell.xmission.com> <l34an4$ic1$1@dont-email.me>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Injection-Info: mx05.eternal-september.org; posting-host="c75a2e3068ccf6c98395286f3e40b97d"; logging-data="5756"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX1/7SgtT54k22iiolDcGU5el"
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.3 (gnu/linux)
Cancel-Lock: sha1:n5GTExWtYdaG66di4imH8xl2vCw= sha1:ewX+qqZhW50yjUGrzKqFzHMSGpw=
Xref: csiph.com comp.lang.java.programmer:26260

markspace <markspace@nospam.nospam> writes:

> On 10/9/2013 12:08 PM, Jim Janney wrote:
>>
>> Thanks.  But that looks like a good idiom to avoid.  I prefer
>>
>>     MyResource r1 = openResource();
>>     try {
>>        MyResource r2 = openResource2();
>>        try {
>>          //  do something
>>        } finally {
>>          r2.close();
>>        }
>>     } finally {
>>       r1.close();
>>     }
>>
>> Not as pretty syntactically, perhaps, but much clearer semantically.
>>
>
> I don't like either one.  Why not take advantage of the fact that
> resources are specified to be closed in the opposite order that they
> are declared in a try-with-resources?
>
> The following demonstrates this by closing the named streams in the
> order C-B-A:
>
>
> package quicktest;
>
> import java.io.IOException;
> import java.io.InputStream;
>
> public class TryResourcesTest
> {
>    public static void main( String[] args ) throws Exception
>    {
>       try(
>           MyTestStream a = new MyTestStream( "A" );
>           MyTestStream b = new MyTestStream( "B" );
>           MyTestStream c = new MyTestStream( "C" )
>       ) {
>          System.out.println( a.read()+b.read()+c.read() );
>       }
>    }
> }
>
> class MyTestStream extends InputStream {
>
>    private final String name;
>
>    public MyTestStream( String name )  {
>       this.name = name;
>    }
>
>    @Override
>    public int read() throws IOException  {
>       return 42;
>    }
>
>    @Override
>    public void close() {
>       System.out.println( getClass().getSimpleName()+
>        ":"+name+" closed." );
>    }
> }

Yes, in Java 7 you can have clean syntax and clean semantics.  Looks
like a win all around.

-- 
Jim Janney