Re: btree on disk

Hello All,

That was really helpful. Thanks.

I also noticed FSFiler, and HashFiler. Are those for Indexing files?

I am working on a graph database project. I have tried several oodbms, and
finally decided to build my own.

Also, could it be possible to use xindice as a backend for Jena?

On 7/6/07, Vadim Gritsenko <[email protected]> wrote:
>
> Cam Bazz wrote:
> > Hello Vadim;
> >
> > I have been looking and experimenting with BFiler. So far, I have been
> > able to insert into BTree,
> > but I have not been able to write to disk. (the initially created file
> > stays at same size).
> >
> > Best Regards,
> > -C.B
> >
> > //
> > Configuration config = new
> > Configuration(DOMParser.toDocument(Xindice.DEFAULT_CONFIGURATION),
> false);
>
> That is not valid configuration for the filer.
>
>
> > BTreeFiler btf = new BTreeFiler();
> >
> > btf.setConfig(config);
> >
> > File file = new File("c:\\");
> > btf.setLocation(file, "test");
> > btf.create();
> >
> > // this works and does indeed inserts to the btree
> > for(int i=0; i<100000; i++)
> > {
> >    btf.addValue(new Value("hello"+i), i);
> > }
> >
> > // this throws an exception saying page file not open.
> > btf.writeRecord(new Key("key"), new Value("val"));
>
> You have to open it before writing stuff in it. Please see BTreeFilerTest
> and
> FilerTestBase test classes, they have everything you need.
>
> Vadim
>
>
> > btf.close();
> >
> > On 7/5/07, *Vadim Gritsenko* <[email protected]
> > <mailto:[email protected]>> wrote:
> >
> >     Cam Bazz wrote:
> >      > Hello Developers,
> >      >
> >      > I have been looking for a solid implementation of a Java BTree on
> >     disk
> >      > for the longest time. Could it be possible to use xindices btree
> >     on disk
> >      > seperately.
> >      > If so, where would be a good place to start. I have looked at the
> >     source
> >      > code, instantiated a new BTree and added values to it, but I got
> >     a null
> >      > pointer exception saying that the file was not opened.
> >
> >     I don't think you can use BTree class directly. Take a look at
> >     BTreeFiler - that
> >     should be better fit. Once you instantiate it, you need to pass in
> >     configuration
> >     and open it. Once you are done working with it, it needs to be
> closed.
> >
> >     See also org.apache.xindice.core.Collection, there you can see how
> >     to work with
> >     Filers.
> >
> >     PS Have you seen JISP?
> >
> >     Vadim
> >
> >     [1] http://www.coyotegulch.com/products/jisp/
> >     <http://www.coyotegulch.com/products/jisp/>
>
>