Accessing Alfresco's JCR

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hananherzog

Hello,
    I have an existing CMS. I would like to use Alfresco's implementation of JSR-170 to be the back-end store. Can you point me to the most straight-forward code-sample with which I can "instantiate/initialize" the JCR back-end (I guess through some sort of factory)? In the meantime, I will try to find out by going through the code.

Thanks,

Hanan

rdanner

Hello,
    I have an existing CMS. I would like to use Alfresco's implementation of JSR-170 to be the back-end store. Can you point me to the most straight-forward code-sample with which I can "instantiate/initialize" the JCR back-end (I guess through some sort of factory)? In the meantime, I will try to find out by going through the code.

Thanks,

Hanan

Is your application already expecting to consume a jcr repository?  At the moment alfresco only supports level I of the JCR spec (read only is the easiest way to describe it.)   They are working on level II at the moment. 

How are you planning to run the repository?  In the same jvm?  rebuild the app on top of a jcr implementation?  pick up a jcr reference from JNDI?

just curious.

The best example is the simple example located in the alfresco jcr project  located in the eamples folder in the alfresco source distribution.


In case you dont want to get that… here is a fragment for reading a document:

   public byte[] retrieveContent(String pContentMoniker)
   throws RetrievalFailureException
   {  
      /* define locals */
      byte[] vRetContentBytes = null;
      Repository vInstJcrRepository = null;
      String vInstUsername = null;
      String vInstPassword = null;
      TransactionProvider vInstTransactionProvider = null;
      Session vSession = null;
      Credentials vCredentials = null;
      UserTransaction vTransaction = null;
      Node vContentNode = null;
      Property vContentProperty = null;
      Value vContentPropertyValue = null;
      int vByteCount = 0;
      
      /* initialize */
      vInstJcrRepository = getJavaContentRepository();
      vInstTransactionProvider = getTransactionProvider();
      vInstUsername = getUsername();
      vInstPassword = getPassword();
      
      try
      {
         vCredentials = new SimpleCredentials(vInstUsername, vInstPassword.toCharArray());
         vSession = vInstJcrRepository.login(vCredentials);

         if(vInstTransactionProvider!=null)
         {
            vTransaction = vInstTransactionProvider.provideUserTransaction();
            vTransaction.begin();
         }

         vContentNode = vSession.getNodeByUUID(pContentMoniker);   

         if(vContentNode!=null)
         {            
            vContentProperty = vContentNode.getProperty("cm:content");
            vContentPropertyValue = vContentProperty.getValue();
            
            vByteCount = vContentPropertyValue.getStream().available();
            vRetContentBytes = new byte[vByteCount];
            
            vContentPropertyValue.getStream().read(vRetContentBytes);
         }
      }
      catch(Exception eRepositoryFailure)
      {
         System.out.println("repository failure ["+eRepositoryFailure+"]");

         try{ if(vTransaction!=null){ vTransaction.rollback(); } }catch(Exception eMuted){}         
      }
      finally
      {
         try{ if(vTransaction!=null){ vTransaction.commit(); } }catch(Exception eMuted){}         
      }

      return vRetContentBytes;
   };
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Initializing the repository (in the case of the example: the value behind getJavaContentRepository()) is a matter of implementation.  Like I said before you can do it any number of a hundred different way.

The easiest is to build right on top of alfresco by including alfrescos jars and spring configuration in you app.  In this case you would just wire the jcr interface to your consuming classes with spring.

This approach is not so hot unless you are looking to embed alfresco or unless you just want to play.

An alternative approach is to load alfresco in one context, register the alfresco jcr repository implemenation bean in JNDI and load you app up in a different context looking to JNDI for a repository.

In addition to that you can put any number of remote mechanisms between your application and the real deal so to speak.  RMI will work well if you are geographically close and have no firewalls to deal with.  Web services works as well if you have to talk on port 80.  Both will incurr a performance penalty.

Hope this helps