Hi Sergio, Thank you for your answers. I am currently trying to set up my eclipse environment so that I can start working with Marmotta's code. As I said, "git, maven, Apache way" are all new things for me, so please excuse my "newbie" questions. My first goal was: to build the all project locally, run my locally built Marmotta, and then start adding components. But my first concern now that I am digging deeper, is that Marmotta is a pretty big project (about 80 projects), and so you might recommand me not to import the main "pom.xml" in my eclipse environment, but start smaller ? If there is already a documentation about how to procede, thank you to point me there, I didn't find any by myself. Nevertheless, I do have problems and errors in Eclipse, and hope you can help me about that. First, I did fork Marmotta, and create a new branch "dev-overLOD" from the "develop" branch. You said in the previous mail that this might be an unnecessary step as we are not touching the core of Marmotta, but actually we might contribute to some changes or improvement if needed. I did "fork" and "branch" just following instructions you gave to QiHong, so if that is not "wrong", I'll go on from there. I did install Eclipse Luna that comes with m2e 1.5 (Maven 3.2.1), and Java 7. I import an "existing Maven project" -> by pointing to the main folder of my "dev-overLOD" branch. The first problems I do have, are with many "Plugin execution not covered by lifecycle configuration" errors. Is there a way to correct that ? I see that QiHong and other people on the Marmotta forum did have the same problems, and you just told them to ignore that as they don't need a full build. But my goal was to be able to produce a full build. So far, I did change the Eclipse setting for Maven "Errors/Warning", and set the "Plugin execution not covered by lifecycle configuration" to "warnings" instead of "errors". Than I do have 6-7 : "Project build error: Non-resolvable parent POM: Could not find artifact org.apache.marmotta:marmotta-parent:pom:3.2.1-SNAPSHOT and 'parent.relativePath' points at wrong local POM pom.xml /marmotta-backend-sparql line 23 Maven pom Loading Problem" and here I am pretty confused: it seems that some POM files are not up-to-date in this 3.3.0 current version, as they do still point to a "3.2.1" parent POM file, but the parent is already in its "3.3.0" version ? Then, apart from those Maven errors, I do have a few java errors with many "imports" or "types" which can't be resolved, and this seems very strange to me. But maybe solving the main Maven problems here above would correct that ? Here is an example "Category cannot be resolved to a type AtomParser.java /marmotta-rio-rss/src/main/java/org/apache/marmotta/commons/sesame/rio/rss line 190 Java Problem" A first goal for me would be to update the Marmotta's main menu so that under "Others", next to "Linked Data Caching", I could have a "External Data Sources" menu and then work an that new module as discussed earlier with you. By the way, any idea/discussion about how should that module work is welcome, as it seems to me it will be a main feature for future real-life applications based on RDF (and other structured data). Thank you for any help/explanation about how I should go on.
Fabian >>> Sergio Fernández<[email protected]> 25.08.2014 14:29 >>> Hi Fabian, On 22/08/14 09:19, Fabian Cretton wrote: > I hope you are well, and I am coming back to you as I will start these > days to understand better Marmotta and see (hopefully with your help) > how the features we are thinking of in OverLOD could be implemented. > > There are quiet a few questions in this email, hope you can answer them > so that I can move on more efficiently. Thank you in advance. The community will try to help us when possible, sure. > In a former email your were pointing me towards Fusepool, saying > "Actually looking to the idea, technologically talking it does not look > so different to what the Fusepool P3 FP7 project tries to do. " > I thus had a look at Fusepool, but from what I saw, Fusepool is about > "creating" RDF from non-RDF resources, whereas OverLOD is mainly about > consuming existing RDF data and have it at disposal for a specific > platform and use-case. > So one goal of OverLOD is more about the "next steps" of the semantic > web: how to consume efficiently RDF, and then make it easier for non-RDF > developpers to use the data. I may got it wrong. Sure, the goal looks different. And very important and careless one. Let's see what progress OverLOD is able to do :-) > About developpment > Apache developpment is a new world for me, but some colleagues here > might help me. > Also I will follow the instruction you gave to QiHong earlier this > year, and so I will start to fork marmotta if I am not mistaken (git and > github are also new to me). > > So I will do the same, and thus, in my fork, create a branch from > 'develop' -> is there a name you recommand me ? do I need to create > 'Issues' about OverLOD features ? Wekk, forking the repo from github could be also useful. But since you are not going to modify the core of Marmotta (right|?), just depending on the Maven level should be more than enough for you. Please, report as Jira issues all problems and/or needs you may have. > As you pointed out "For me the "OverLOD Referencer" has a big potential > of reusing the infrastructure provided by LDClient [2 ( > http://marmotta.apache.org/ldclient/ )] and LDCache [3 ( > http://marmotta.apache.org/ldcache/ )]." > LDClient seems the way to import external data into Marmotta. I don't > see LDClient on the "Platform Architecture Overview". > This external data could be RDF, or data that needs to be RDFized, > right ? > The first question is the one already expressed here above: does > LDClient already handle the automatic update of the data once the data > source have been modified ? (I only read about some time-out features > but don't know yet what it means). > Second question is about the RDFizers: there is a nice list of RDFizer > listed, but nothing about Microdata/Microformat, would that be something > to implement if needed ? > > Then, LDCache does handle where to store the incoming data from > LDClient. But is this storage different from the main Marmotta storage ? > Are the imported data part of the default graph and queryable > transparently with the other data from the LDP ? I guess so, but from > what I read I did have some doubts. Shortly: * LDClient is a library to access resources as Linked Data, not only directly Linked Data resources, but also allowing the transformation of non-Linked data resource into Linked Data (RDF). It comes with some data providers http://marmotta.apache.org/ldclient/dataproviders, but it can be extended to support new ones, such as for Microdata. * LDCache is the infrastructure built on top of LDClient to automatically retrieve (cache) data from different sources. Further details at: http://marmotta.apache.org/ldcache These two libraries are use in the Marmotta platform to automatically cache in the triple store (under an special named graph / context) data, and keep it updated according the configuration. Hope that helps. Cheers, -- Sergio Fernández Partner Technology Manager Redlink GmbH m: +43 660 2747 925 e: [email protected] w: http://redlink.co
