Re: Newbie questions regarding jgit

From: Farrukh Najmi <farrukh@wellfleetsoftware.com>
Date: Nov 12, 2008, 14:33 UTC
Message-ID: <491AE91C.4020402@wellfleetsoftware.com>
In-Reply-To: <491AE2BD.7080103@wellfleetsoftware.com>

BTW, the context for what I am doing is as follows. I am implementing OASIS ebXML Registry/Repository (RegRep) 4 specs:

<http://www.oasis-open.org/committees/download.php/29972>

I would like to use git for the Repository part of the RegRep while a relational database will hold the registry part which contains extensive metadata about repository files. Later I will also evaluate if I can somehow use git for the Registry part so I can leverage versioning features of git. I would still need to have the Registry content duplicated in relational database to support querying of the metadata. The standard eventually needs to support CheckIn/Checkout and I think a distributed VCS like git would be very helpful in an implementation.

For those unfamiliar with RegRep as a technology think of it as providing added value on top of a generic VCS, database or Content Management system.

For my immediate needs, I need to implement a GitRepository class with two methods using gjit as shown below. I would appreciate any guidance and pseudo-code examples on how to implement these methods. Please keep in mind that I am just getting to know git itself and gjit was key to my considering git over Mercurial and other distributed VCSs.

public class GitRepositoryManager {

    Repository gitRepo;

...

    /**
     * Gets the content of specified file in git Repo.
     *
     * @parameter relativePath the relative path in jitRepo for  desired 
file to get
     * @parameter versionName the versionName for the desired file. It 
will be unmarshalled from String to ObjectId.
     * @return the content of the desired file version packaged as a 
DataHandler.
     */
    public DataHandler get(String relativePath, String versionName) 
throws RepositoryException {
        DataHandler dh = null;

        ...
       
        return dh;
    }

    /**
     * Creates a new version of specified version of file in git Repo.
     *
     * @parameter relativePath the relative path in jitRepo for  desired 
file to get
     * @parameter versionName the versionName for the desired file. It 
will be unmarshalled from String to ObjectId.
     * @parameter content the content of the new version for specified 
file packaged as a DataHandler.
     */
    public void update(String relativePath, String versionName, 
DataHandler content) throws RepositoryException {
        ...
    }

Farrukh Najmi wrote:

Show 52 quoted lines

> Jonas Fonseca wrote:
> ...
>>  
>>> Now I am wondering where to begin to learn how to do the equivalent 
>>> of the
>>> following commands via the gjit Java API:
>>>
>>>   * git add /file/
>>>   * git rm /file/
>>>   * git mv /file
>>>   * Whatever is the git way to get a specific version of a file
>>>     
>>
>> JGit currently has two APIs for working with the index, which will
>> allow you to add, remove and move data around in the tree. In nbgit I
>> ended up using GitIndex, which I found easier to figure out. As I
>> understand it, in the long run you want to use the DirCache API, but
>> it is still a work in progress.
>>   
>
> I am happy to use GitIndex now and switch to DirCache API later when 
> it is ready.
> Can I please get some pseudo-code fragments on how to do the use cases 
> I identified above?
> The javadoc is still not obvious to me.
>>  
>>> I am hoping that there aremore docs, samples, tutorials etc. 
>>> somewhere that
>>> I am missing. Thanks for any help you can provide. Some pointers or 
>>> code
>>> fragments would be terrific.
>>>     
>>
>> I started working on a tutorial for JGit, but didn't get very far so
>> it mostly consists of stub pages.
>>
>>  - http://code.google.com/docreader/#p=egit&s=egit&t=JGitTutorial
>>
>> I have been working on moving the tutorial to maven project before
>> starting to write the more code heavy topics. This would make it
>> possible to include code snippets in the tutorial, while also allowing
>> to compile and test the examples.
>>   
>
> The wiki is an awesome resource even in its current state. Thank you.
> I would be glad to help contribute improvements to wiki if you give me
> write privilege. What I could do is take the help I get from the list and
> then update wiki carefully as appropriate if you want me to help.
>
> Thanks again to all of you for helping get me bootstrapped with gjit 
> and git.
>

-- 
Regards,
Farrukh Najmi

Web: http://www.wellfleetsoftware.com