[brailleblaster] Re: Start of Editor
- From: "John J. Boyer" <john.boyer@xxxxxxxxxxxxxxxxx>
- To: brailleblaster@xxxxxxxxxxxxx
- Date: Sat, 13 Nov 2010 12:44:49 -0600
Thanks. This is good inforrmation, and I'll keep it on hand. As Sina
suggested, we will start by just assigning lots of memory to the JMV and
later look into memory compaction. Your information will come in handy
then.
John
On Sat, Nov 13, 2010 at 10:14:05AM -0800, Chris von See wrote:
> You might find this comparison of in-memory XML representations
> interesting:
> http://softwaredevscott.spaces.live.com/blog/cns!1A9E939F7373F3B7!443.entry
>
> If you're really concerned about memory usage and don't want to use
> XML-to-Java bindings, you might consider implementing something like
> the SAXON TinyTree
> (http://www.stylusstudio.com/api/saxon8/net/sf/saxon/tinytree/package-summary.htm
>
> ) that tokenizes strings and can significantly reduce memory footprint.
>
>
> Cheers
> Chris
>
> On Nov 13, 2010, at 6:24 AM, John J. Boyer wrote:
>
> >After thinking some more, I agree with you. In our scripts which call
> >the Java runtime we can simply specify minimum memory as 200 MB and
> >maximum memory as 500 MB.
> >
> >John
> >
> >On Sat, Nov 13, 2010 at 08:54:46AM -0500, Sina Bahram wrote:
> >>Memory compaction can actually happen for free depending on what
> >>technologies we use. Also, I wouldn't worry too much about this
> >>because these kinds of optimizations can be performed once the
> >>product is complete.
> >>
> >>Don't forget the entropy in this data is so low so as to almost be
> >>considered partially ordered E.G. more than 50% compression
> >>ratios on any arbitrary subsection.
> >>
> >>Take care,
> >>Sina
> >>
> >>-----Original Message-----
> >>From: brailleblaster-bounce@xxxxxxxxxxxxx
> >>[mailto:brailleblaster-bounce@xxxxxxxxxxxxx ] On Behalf Of John J. Boyer
> >>Sent: Saturday, November 13, 2010 2:11 AM
> >>To: brailleblaster@xxxxxxxxxxxxx
> >>Subject: [brailleblaster] Re: Start of Editor
> >>
> >>What I want to do is make the value of the index attribute more
> >>compact before it is incorporated into the DOM tree. Take the
> >>following example.
> >>Suppose we have a paragraph for which the braille translation is
> >>500 characters long. For each of these characters we have a decimal
> >>number followed by a comma. Taking only the characters above
> >>position 100, each will correspond to four characters iin the
> >>attribute
> >>value. Each of these four characters will be translated into a 16-
> >>bit (two byte) character in the string representing the value.
> >>This will result in 400
> >>* 4 * 2 bytes needed to represent this attribute. I've been
> >>entertaining the possibly wild idea of converting the decimal
> >>number at
> >>each position to a short and then putting all these shorts together
> >>into a new string which would replace the old. This would
> >>require only 800 bytes.
> >>Subsequent processing would also be easier, since the program would
> >>need to only convert the string into a char array and athen
> >>index through it.
> >>Of course, such a string would have to be reconverted to the
> >>original on output.
> >>
> >>I'm perhaps overly concerned about memory usage. My estimate is
> >>that an ordinary document could take over 100 MB of memory. Large
> >>ones might take twice that. Compaction of the index attribute would
> >>reduce this by maybe two-thirds. If we don't compact we should
> >>assign about 400 MB to the JVM.
> >>
> >>John
> >>
> >>On Fri, Nov 12, 2010 at 08:48:22PM -0500, Sina Bahram wrote:
> >>>Modifying that code is not how you'd want to go about doing this.
> >>>
> >>>You'd want to either hook in externally, through published and
> >>>accepted means, or simply do the processing on the dom where such
> >>>semantics are more clearly available anyways.
> >>>
> >>>Take care,
> >>>Sina
> >>>
> >>>-----Original Message-----
> >>>From: brailleblaster-bounce@xxxxxxxxxxxxx
> >>>[mailto:brailleblaster-bounce@xxxxxxxxxxxxx] On Behalf Of John J.
> >>>Boyer
> >>>Sent: Friday, November 12, 2010 8:24 PM
> >>>To: brailleblaster@xxxxxxxxxxxxx
> >>>Subject: [brailleblaster] Re: Start of Editor
> >>>
> >>>Thanks for the info. I'm still just a beginning Java programmer,
> >>>so i
> >>>have some wild ideas. What I was thinking of was using Sax to modify
> >>>some things before JDOM builds the parse tree. For example,
> >>>putting the value of the index attribute on the <brl> tag in a more
> >>compact and easily-processed form.
> >>>
> >>>John
> >>>
> >>>On Fri, Nov 12, 2010 at 08:08:26AM -0800, Chris von See wrote:
> >>>>I would be interested to hear more about why you want to modify
> >>>>JDOM.
> >>>>I've built many parse trees and other similar structures using the
> >>>>SAX callbacks documented in the "org.xml.sax" package in the JDK;
> >>>>if
> >>>>you're using Java 6 you can also use the stream-oriented StAX
> >>>>classes in the "javax.xml.stream" package, which may be a bit
> >>>>easier
> >>>>to deal with. In both cases you'd be using SAX or StAX to read the
> >>>>input tree and JDOM to build your parse tree instead of modifying
> >>>>the tree built by JDOM, which is a little bit more work but IMO
> >>>>much
> >>>>cleaner and easier to maintain.
> >>>>
> >>>>Cheers
> >>>>Chris
> >>>>
> >>>>
> >>>>
> >>>>On Nov 12, 2010, at 12:27 AM, John J. Boyer wrote:
> >>>>
> >>>>>A few weeks ago I sent the eclipse.swt TextEditor as an
> >>>>>attachment.
> >>>>>On this message I am attaching SAXBuilderDemo.java from the JDOM
> >>>>>samples directory. I also resending TextEditor.java for your
> >>>>>convenience. I think that we can combine these two to get a
> >>>>>start on our editor.
> >>>>>
> >>>>>One thing I would like advice on is the copyright notice that
> >>>>>should appear at the beginning of each class. I could copy the
> >>>>>liblouis copyright notice with appropriate changes, but you will
> >>>>>notice that the authors already have some conditions that they
> >>>>>wish
> >>>>>respected. We will be modifying their code, of course. We may also
> >>>>>want to dig down to the SAX level so we can modify the parse tree
> >>>>>as it is being built. This will mean modifying a few classes in
> >>>>>JDOM itself. Eclipse may also have some conditions on the reuse
> >>>>>of their code.
> >>>>>
> >>>>>Please give your comments and suggestionsj regarding the copytight
> >>>>>issue.
> >>>>>
> >>>>>Thanks,
> >>>>>John B.
> >>>>>
> >>>>>--
> >>>>>John J. Boyer; President, Chief Software Developer Abilitiessoft,
> >>>>>Inc.
> >>>>>http://www.abilitiessoft.com
> >>>>>Madison, Wisconsin USA
> >>>>>Developing software for people with disabilities
> >>>>>
> >>>>><SAXBuilderDemo.java><TextEditor.java>
> >>>>
> >>>>
> >>>
> >>>--
> >>>My websites:
> >>>GodTouches Digital Ministry, Inc. http://www.godtouches.org
> >>>Abilitiessoft, Inc. http://www.abilitiessoft.com
> >>>Location: Madison, WI, USA
> >>>
> >>>
> >>
> >>--
> >>John J. Boyer; President, Chief Software Developer Abilitiessoft,
> >>Inc.
> >>http://www.abilitiessoft.com
> >>Madison, Wisconsin USA
> >>Developing software for people with disabilities
> >>
> >>
> >>
> >
> >--
> >My websites:
> >GodTouches Digital Ministry, Inc. http://www.godtouches.org
> >Abilitiessoft, Inc. http://www.abilitiessoft.com
> >Location: Madison, WI, USA
> >
> >
>
--
John J. Boyer; President, Chief Software Developer
Abilitiessoft, Inc.
http://www.abilitiessoft.com
Madison, Wisconsin USA
Developing software for people with disabilities
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