Re: Pull NamedModel from a Dataset didn't work since jena 3.1.1
Thanks, I've made that change. Keep in mind that if you see an error on a doc page, you can always use the "Improve this Page" link at the top of the page to send a patch. --- A. Soroka The University of Virginia Library > On Feb 14, 2017, at 11:21 AM, marschelin...@web.de wrote: > >> That link works fine for me and leads to appropriate documentation. Perhaps >> you can explain what you mean by "it is not a correct linking"? > > I don't mean the link "http://jena.apache.org/documentation/rdfconnection/";. > I speak from the link at the bottom of this site in the section "Examples". > The link is a plain text and no correct html link. The link at the bottom is > "https://github.com/apache/jena/tree/master/jena-rdfconnection/src/main/java/rdfconnection/examples";. > And this leads me to an error page. ;) > > I think the link for the example page must be > "https://github.com/apache/jena/tree/master/jena-rdfconnection/src/main/java/org/apache/jena/rdfconnection/examples";. > > Greetings, > > Roman > >>> On Feb 14, 2017, at 3:56 AM, marschelin...@web.de wrote: >>> >>> For your information the linking in the example section on the page >>> "http://jena.apache.org/documentation/rdfconnection/"; don't work correct. >>> First it is not a correct linking and second the link > > leads me to an >>> error page. >
Re: Pull NamedModel from a Dataset didn't work since jena 3.1.1
> That link works fine for me and leads to appropriate documentation. Perhaps > you can explain what you mean by "it is not a correct linking"? I don't mean the link "http://jena.apache.org/documentation/rdfconnection/";. I speak from the link at the bottom of this site in the section "Examples". The link is a plain text and no correct html link. The link at the bottom is "https://github.com/apache/jena/tree/master/jena-rdfconnection/src/main/java/rdfconnection/examples";. And this leads me to an error page. ;) I think the link for the example page must be "https://github.com/apache/jena/tree/master/jena-rdfconnection/src/main/java/org/apache/jena/rdfconnection/examples";. Greetings, Roman > > On Feb 14, 2017, at 3:56 AM, marschelin...@web.de wrote: > > > > For your information the linking in the example section on the page > > "http://jena.apache.org/documentation/rdfconnection/"; don't work correct. > > First it is not a correct linking and second the link > > leads me to an > > error page.
Re: Pull NamedModel from a Dataset didn't work since jena 3.1.1
That link works fine for me and leads to appropriate documentation. Perhaps you can explain what you mean by "it is not a correct linking"? --- A. Soroka The University of Virginia Library > On Feb 14, 2017, at 3:56 AM, marschelin...@web.de wrote: > > For your information the linking in the example section on the page > "http://jena.apache.org/documentation/rdfconnection/"; don't work correct. > First it is not a correct linking and second the link leads me to an error > page.
Aw: Re: Pull NamedModel from a Dataset didn't work since jena 3.1.1
> Hi Roman,
>
> You should get a "TDBTransactionException: Not in a transaction". It is
> not possible to pass
>
There is unfortunately no error message in my jetty log file.
>
>
> On 13/02/17 15:55, marschelin...@web.de wrote:
> > Hi,
> >
> > I tried update Jena from 3.1.0 to 3.2.0. And at a later point I tried to
> > update to Jena 3.1.1. In both cases I had the problem, that the following
> > code didn't work anymore.
> >
> > public Model pullNamedModelFromTDB(String pathToTDB, String modelURI) {
> > // create a TDB-dataset
> > Dataset dataset = TDBFactory.createDataset(pathToTDB);
> > dataset.begin( ReadWrite.WRITE );
> > try {
> > // get the named model from the dataset
> > Model tdb = dataset.getNamedModel(modelURI);
>
> This does not copy it out of the dataset, it creates a view of the data
> inside the dataset, in fact, a view
Good to know. It works for me in the past.
>
> > // finish the "WRITE" transaction
> > dataset.commit();
> > return tdb;
> > } finally {
> > // close the dataset
> > dataset.end();
> > dataset.close();
>
> No needed. close(), if it has any meaning, may close the dataset for
> ever. It's all cached internally.
>
> > // write a message if the data was successfully find in the jena tdb
> > System.out.println("The model " + modelURI + " was successfully loaded
> > from directory: " + pathToTDB);
> > }
> > }
> >
> > Model defaultCompositionModel;
> >
> > defaultCompositionModel =
> > connectionToTDB.pullNamedModelFromTDB(currDirectoryPath,
> > defaultCompositionNGURI);
> > System.out.println("close test = " + defaultCompositionModel.isClosed());
> > System.out.println("empty test = " + defaultCompositionModel.isEmpty());
> >
> > The program stops immediatly when I try to access the data of the named
> > model.
>
> With an exception, I hope.
See first comment.
>
> > So is there a new/correct way to pull a Named Model from a Dataset to
> > use it afterward? The Code above works fine with the old
> > versions(3.1.0 & 3.0.0). I saw there was a change in
> > "DatasetImpl.java"-code. A variable called "dftModel" was removed
> > from the code. I also saw that there was a change on Feb 8, 2017,
> > where an if-statement was added for the transformation from a graph
> > in a model.
>
> The correct ways depends on what you want to do:
>
> A:: If you want to copy out the model, then create a memory model and
> copy with model.add(tdb) to create an in-memory detached copy.
>
> See also the new RDF Connection:
> http://jena.apache.org/documentation/rdfconnection/
> This provides whole graph operations - better than DataseAccessor.
> It can operate in copy-out, copy-in mode, makign it liek a remote
> connection and also for making it transaction safe.
This way works for me. I want to copy a named graph from the jena tdb. Change
some resources and want to save the "copied graph" into another dataset.
the case with the memory model only works for me when I use the new Java class
RDFConnection. So it works in Jena 3.2.0 but not in Jena 3.1.1.
For the record, if somebody else is looking for a working way, this is my code
snippet:
public Model pullNamedModelFromTDB(String pathToTDB, String modelURI) {
// create a TDB-dataset
Dataset dataset = TDBFactory.createDataset(pathToTDB);
try (RDFConnection conn = RDFConnectionFactory.connect(dataset)) {
conn.begin(ReadWrite.WRITE);
try {
Model model = conn.fetch(modelURI);
Model outputModel =
ModelFactory.createDefaultModel().add(model);
conn.commit();
return outputModel;
} finally {
// close the connection
conn.end();
// write a message if the import was successfully
System.out.println("The model " + modelURI + " was successfully
loaded from directory: " + pathToTDB);
}
}
}
For your information the linking in the example section on the page
"http://jena.apache.org/documentation/rdfconnection/"; don't work correct. First
it is not a correct linking and second the link leads me to an error page.
Thanks for all,
Roman
Re: Pull NamedModel from a Dataset didn't work since jena 3.1.1
Hi Roman,
You should get a "TDBTransactionException: Not in a transaction". It is
not possible to pass
On 13/02/17 15:55, marschelin...@web.de wrote:
Hi,
I tried update Jena from 3.1.0 to 3.2.0. And at a later point I tried to update
to Jena 3.1.1. In both cases I had the problem, that the following code didn't
work anymore.
public Model pullNamedModelFromTDB(String pathToTDB, String modelURI) {
// create a TDB-dataset
Dataset dataset = TDBFactory.createDataset(pathToTDB);
dataset.begin( ReadWrite.WRITE );
try {
// get the named model from the dataset
Model tdb = dataset.getNamedModel(modelURI);
This does not copy it out of the dataset, it creates a view of the data
inside the dataset, in fact, a view
// finish the "WRITE" transaction
dataset.commit();
return tdb;
} finally {
// close the dataset
dataset.end();
dataset.close();
No needed. close(), if it has any meaning, may close the dataset for
ever. It's all cached internally.
// write a message if the data was successfully find in the jena tdb
System.out.println("The model " + modelURI + " was successfully loaded from
directory: " + pathToTDB);
}
}
Model defaultCompositionModel;
defaultCompositionModel =
connectionToTDB.pullNamedModelFromTDB(currDirectoryPath,
defaultCompositionNGURI);
System.out.println("close test = " + defaultCompositionModel.isClosed());
System.out.println("empty test = " + defaultCompositionModel.isEmpty());
The program stops immediatly when I try to access the data of the named model.
With an exception, I hope.
So is there a new/correct way to pull a Named Model from a Dataset to
use it afterward? The Code above works fine with the old
versions(3.1.0 & 3.0.0). I saw there was a change in
"DatasetImpl.java"-code. A variable called "dftModel" was removed
from the code. I also saw that there was a change on Feb 8, 2017,
where an if-statement was added for the transformation from a graph
in a model.
The correct ways depends on what you want to do:
A:: If you want to copy out the model, then create a memory model and
copy with model.add(tdb) to create an in-memory detached copy.
See also the new RDF Connection:
http://jena.apache.org/documentation/rdfconnection/
This provides whole graph operations - better than DataseAccessor.
It can operate in copy-out, copy-in mode, makign it liek a remote
connection and also for making it transaction safe.
B:: If you want to change the model and change the dataset, then get the
model inside a transaction each time. It isn't a copy - it should not
be expensive.
Passing anything that is associated with the transaction out of the
begin-commit is not safe. It used to lead to missing updates. It sort
of worked for read-only operations although that could go wrong as well.
"dftModel" - this is related - the code no longer holds on to default
model across transactions.
Feb 8 - after the release. It is actually making an error situation
happen earlier and with a relevant error message. In TDB all graphs
"exist" so the return is never null and so this is not relevant here.
Andy
Thanks in advance!
Roman
Pull NamedModel from a Dataset didn't work since jena 3.1.1
Hi,
I tried update Jena from 3.1.0 to 3.2.0. And at a later point I tried to update
to Jena 3.1.1. In both cases I had the problem, that the following code didn't
work anymore.
public Model pullNamedModelFromTDB(String pathToTDB, String modelURI) {
// create a TDB-dataset
Dataset dataset = TDBFactory.createDataset(pathToTDB);
dataset.begin( ReadWrite.WRITE );
try {
// get the named model from the dataset
Model tdb = dataset.getNamedModel(modelURI);
// finish the "WRITE" transaction
dataset.commit();
return tdb;
} finally {
// close the dataset
dataset.end();
dataset.close();
// write a message if the data was successfully find in the jena tdb
System.out.println("The model " + modelURI + " was successfully loaded from
directory: " + pathToTDB);
}
}
Model defaultCompositionModel;
defaultCompositionModel =
connectionToTDB.pullNamedModelFromTDB(currDirectoryPath,
defaultCompositionNGURI);
System.out.println("close test = " + defaultCompositionModel.isClosed());
System.out.println("empty test = " + defaultCompositionModel.isEmpty());
The program stops immediatly when I try to access the data of the named model.
So is there a new/correct way to pull a Named Model from a Dataset to use it
afterward? The Code above works fine with the old versions(3.1.0 & 3.0.0). I
saw there was a change in "DatasetImpl.java"-code. A variable called "dftModel"
was removed from the code. I also saw that there was a change on Feb 8, 2017,
where an if-statement was added for the transformation from a graph in a model.
Thanks in advance!
Roman
