[Pljava-dev] How to read LargeObject with pljava?

[Oleg Vasylenko]

Hi everybody!

Have some code to read LargeObject from db and create digest message for 
the it content. The code generate an error attemtting to read a portion 
of LO.

Could anybody give an example how to read LO from database?

I'm using jre1.6.0.13, pljava1.4.0, postgresql8.3.7.

Thanks.

import java.io.FileOutputStream;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.logging.Logger;
import org.postgresql.largeobject.LargeObject;
import org.postgresql.largeobject.LargeObjectManager;

public class ServerDigestCreator {


public static String 
anotherCreateStrDigest(org.postgresql.pljava.internal.Oid lObjectId) 
throws  SQLException,NoSuchAlgorithmException
   {
       String digest = null;
       java.sql.Savepoint sp = null;
       if(lObjectId==null) return null;
       java.sql.Connection aConnection = 
DriverManager.getConnection("jdbc:default:connection");
       try{
             sp = aConnection.setSavepoint();
       org.postgresql.pljava.internal.LargeObject lo =  
org.postgresql.pljava.internal.LargeObject.open(lObjectId, 
org.postgresql.pljava.internal.LargeObject.INV_READ);
                 MessageDigest aDigest = MessageDigest.getInstance("md5");
             if(lo==null)       {
               aConnection.releaseSavepoint(sp);
               return digest;
       }
       byte buf[] = new byte[2048];
       int s=0;
         while((s = lo.read(buf))!=0)              
<---------------------- Error occurs here 
=============================================================
               aDigest.update(buf);               byte[] digestByteArray 
= aDigest.digest();
       BigInteger tempBI = new BigInteger(digestByteArray);
       digest = tempBI.toString();             lo.close();
         aConnection.releaseSavepoint(sp);
       }
       catch(SQLException ex)
       {              if(sp!=null)
               aConnection.rollback(sp);
           Logger.getAnonymousLogger().info("ERROR: " + ex.getMessage() 
+ "\n");
           throw new SQLException(ex.getMessage());
       }
             return digest;
   }