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From "Andrew Zhang" <zhanghuang...@gmail.com>
Subject Re: [classlib][lang] AbstractStringBuilder, abstract class?
Date Sun, 08 Oct 2006 00:42:29 GMT
On 10/7/06, Geir Magnusson Jr. <geir@pobox.com> wrote:
>
> sounds reasonable, but don't go based on my word, of course.
>
> Interesting question is why AbstractStringBuilder isn't abstract...


curious too...

Andrew Zhang wrote:
> > On 2/23/06, Nathan Beyer <nbeyer@kc.rr.com> wrote:
> >
> >>
> >> An interesting side note: The "Serialized Form" documentation gives
> away
> >> an
> >> implementation detail of StringBuffer and StringBuilder, in that they
> >> both
> >> extend from an AbstractStringBuilder. This might be an interesting
> >> approach
> >> to consolidate those code paths.
> >
> >
> > Spec lies sometimes? The spec of StringBuilder and StringBuffer claim
> the
> > superclass of them is java.lang.Object, but the serialized form tells
> the
> > truth - they extend from java.lang.AbstractStringBuilder, which is not
> > public.
> >
> > I picked up this thread again because I found an existing application
> > failed
> > against Harmony because of this problem. The scenario is:
> > 1. application runs on jdk1.1
> > 2. new instances of some classes. If a class has superclass, then new an
> > instance of superclass too if it's not abstract or an interface. The
> > pseudo-code looks like:
> > newAllInstances(Class clazz) {
> > if(clazz == null) return;
> > if (clazz is abstract or an interface) return;
> > new an instance of clazz;
> > newAllInstances(clazz.getSuperClass());
> > }
> >
> > The test data includes some instances of StringBuffer. The application
> > fails
> > against Harmony because AbstractStringBuilder is a concrete class but
> not
> > public. The application runs well against sun jdk 1.5 (Although all code
> > are
> > based on jdk1.1) because the superclass is abstract.
> >
> > So is it a reason to change the signature of class
> AbstractStringBuilder?
> > Make it as abstract really as the name suggests?
> >
> > Thanks!
> >
> >
> >
> >> [1]
> >>
> >>
> http://java.sun.com/j2se/1.5.0/docs/api/serialized-form.html#java.lang.Strin
> >>
> >> gBuilder
> >> [2]
> >>
> >>
> http://java.sun.com/j2se/1.5.0/docs/api/serialized-form.html#java.lang.Strin
> >>
> >> gBuffer
> >>
> >>
> >> -----Original Message-----
> >> From: Tim Ellison [mailto:t.p.ellison@gmail.com]
> >> Sent: Wednesday, February 22, 2006 3:09 PM
> >> To: harmony-dev@incubator.apache.org
> >> Subject: Re: [jira] Resolved: (HARMONY-103) java.lang.StringBuilder
> >> Implementation for LUNI
> >>
> >> Nathan,
> >>
> >> First, let me say a big thank you for the code and tests you submitted.
> >> I've had a chance to read through it and (beyond the comments below) it
> >> looks good.
> >>
> >> I've committed a modified version of your patch to SVN.  However, ;-)
> >>
> >> 1.  I've removed the javadoc comments as these appear to be direct
> >> copies of the Sun documentation.  We cannot copy Sun's property.  For
> >> now the comments have been replaced with TODO tags.
> >>
> >> 2.  I've removed the .intern() from the string literals, since these
> >> will be interned by the VM anyway.
> >>
> >> 3.  Why have you got transient char[] and int fields, and then
> serialize
> >> them (as int, char[])?  Wouldn't it be easier to reorder the fields and
> >> remove the readObject/writeObject methods?
> >>
> >> Thanks again for your work,
> >> Tim
> >>
> >>
> >> Tim Ellison (JIRA) wrote:
> >> >      [ http://issues.apache.org/jira/browse/HARMONY-103?page=all ]
> >> >
> >> > Tim Ellison resolved HARMONY-103:
> >> > ---------------------------------
> >> >
> >> >     Resolution: Fixed
> >> >
> >> > Nathan,
> >> >
> >> > Thanks for the patch, it has been applied (minus javadoc) at repo
> >> revision
> >> 379882.
> >> >
> >> > Please check that it has been applied as you expected.
> >> >
> >> >
> >> >> java.lang.StringBuilder Implementation for LUNI
> >> >> -----------------------------------------------
> >> >>
> >> >>          Key: HARMONY-103
> >> >>          URL: http://issues.apache.org/jira/browse/HARMONY-103
> >> >>      Project: Harmony
> >> >>         Type: New Feature
> >> >>   Components: Classlib
> >> >>     Reporter: Nathan Beyer
> >> >>     Assignee: Tim Ellison
> >> >>  Attachments: StringBuilder.java, StringBuilderTest.java
> >> >>
> >> >> This bug is for submitting an implementation of the
> >> java.lang.StringBuilder to the LUNI module of classlib. The
> >> implementation
> >> and class definition is based on the specification at
> >> http://java.sun.com/j2se/1.5.0/docs/api/java/lang/StringBuilder.html.
> >> >> The implementation is not complete, there are a few method that are
> >> either incomplete or not implemented. All of these are related to the
> >> Unicode Code Point support, as defined by Java 5. As for the rest of
> the
> >> implementation, there are probably a number of optimization points, but
> >> the
> >> focus was to complete the functionality and make it compatible with
> >> various
> >> Java 5 runtimes.
> >> >> Additionally, I had a problem with compiling this class in Eclipse
> >> 3.1.2.
> >> When I set the compiler to Java 1.4 compliance level, the methods which
> >> implement the Appendable interface cause compilation errors. When I set
> >> the
> >> compiler to Java 5.0 compliance with Java 1.4 .class file compatability
> >> and
> >> Java 1.4 source compatibility, the class compiled fine. I'm not sure if
> >> this
> >> is quirk of the JDT compiler or what, but I'm going to do some
> >> investigation
> >> and testing to see if I can isolate it.
> >> >
> >>
> >> --
> >>
> >> Tim Ellison (t.p.ellison@gmail.com)
> >> IBM Java technology centre, UK.
> >>
> >>
> >
> >
>
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>


-- 
Best regards,
Andrew Zhang

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