Back to classicism? Zurück zur Klassik. Ein neuer Blick auf das alte Griechenland

 

Following the trend of discovering ancient Greece is a new exhibition in Frankfurt am Main. More details one can find here:

http://kulturfonds-frm.de/projekte/zurueck-zur-klassik-ein-neuer-blick-auf-das-alte-griechenland

One step further for those who have been taught some form of Greek at school, is visiting the available online museums of Greece and reading the literature about it:

http://www.latsis-foundation.org/default.asp?pid=92&la=1&libID=1

Nevertheless, people with no knowledge of Greek, ancient or modern, would also benefit by browsing the pictures of the exhibits, just to get a taste of the aesthetics.
Για  δε τους  απανταχού της γης ελληνόφωνους ή της ελληνικής παιδείας μετέχοντες, το υπουργείο παιδείας προσφέρει δωρεάν όλα τα σχολικά βιβλία εδώ.

Finally, the last step would be to see all these with one's naked eyes, by visiting Greece to enjoy the sunny weather and avail oneself of the particularly low hotel prices, attracting potential tourists worldwide.

Comments on Oracle SOA Infrastructure Implementation certification Handbook (1Z0-451)) by Kathiravan Udayakumar

On the bright side, the text is of average quality written in American English. It is well organized, full of  helpful images though of the older JDeveloper 11.1.1.5 version, with minimal if any tutorials or hands on practice. The author explains clearly some points, such as  the different kinds of BPEL processes, synchronous, asynchronous, one way or bilateral, especially in the early chapters.

On the dark side, the text is full of spelling errors, sentences without a verb, some answers to exams questions (options are A or B only, but the correct answer is  given as C). Furthermore, there are technical errors spread everywhere; consider the example of what happens with already running instances when retiring or shutting down a composite application within the enterprise manager. I quote a sentence found in page 338: "29. b: Shutting down the composite will not terminate the running instance."   No SOA suite setup instructions are given, nor is any source code or errata,  available online. 


All in all, the book offers a spherical but not hands on introduction to the SOA suite. It makes a fairly good certification   primer. Nonetheless, whole topics such as complex event processing and many others are only mentioned in the exam questions, but not in the text itself. It seems the book  was written in haste; some professional reviewing and correction of the text, would be more than desirable!

Processing BLOBs via the ImageServlet

In this post an alternative code version to the traditional ImageServlet  will be given, supplementing the one presented in the book named Oracle Fusion Developer Guide (p.409), by F.Nimphius and L.Munsinger and other official Oracle aces' and employees' blogs. This alternative version will use the  EJB 3 way to get rid of the surplus database definition hard coded in the doGet() method. As an epilogue, further criticism will be provided, against using that technique of obtaining jdbc connections to the database.

Here is the modified code, with the original straight jdbc code commented out:

package actionbazaar.view.servlet;


import actionbazaar.buslogic.PlaceItem;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.OutputStream;

import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import oracle.jbo.domain.BlobDomain;

import org.apache.log4j.Logger;


public class ImageServlet extends HttpServlet {
    private static final String CONTENT_TYPE = "image/jpg; charset=utf-8";
    @SuppressWarnings("compatibility:988932384557339885")
    private static final long serialVersionUID = 1L;
    private Logger logger = Logger.getLogger(this.getClass().getName());
   
    public void init(ServletConfig config) throws ServletException {
        super.init(config);
    }

    public void doGet(HttpServletRequest request,
                      HttpServletResponse response) throws ServletException,
                                                           IOException {
        response.setContentType(CONTENT_TYPE);
        Long itemId = new Long(request.getParameter("itemId"));
        if (logger.isDebugEnabled())
            logger.debug("itemId = " + itemId);
        try {
                Context context = new InitialContext();
                PlaceItem placeItem = (PlaceItem)context.lookup("ejb3inaction-Model-PlaceItem#actionbazaar.buslogic.PlaceItem");
                byte[] image  = placeItem.getImageByItemId(itemId);

            if (image != null) {
                BlobDomain bld = new BlobDomain(image);

                OutputStream os = response.getOutputStream();
                BufferedInputStream in =  new BufferedInputStream(bld.getBinaryStream());
                int b;
                byte[] buffer = new byte[10240];

                while ((b = in.read(buffer, 0, 10240)) != -1) {
                    os.write(buffer, 0, b);
                }
                os.close();
            } else {
                    if (logger.isDebugEnabled())
                        logger.debug("No  image exists yet for itemId: " + itemId);
                }
        } catch (NamingException e){
            e.printStackTrace();   
        }
        catch (IOException e){
            e.printStackTrace();   
        }
       /*
        Connection conn = null;


        try {
            Context ctx = new InitialContext();
//Datasource as defined in <res-ref-name> element of weblogic.xml
            DataSource ds =
                (DataSource)ctx.lookup("jdbc/ActionBazaarEJB3inActionDS");

            conn = ds.getConnection();
            PreparedStatement statement =
                conn.prepareStatement("SELECT IMAGE " +
                                      " FROM ITEMS" +
                                    " WHERE ITEM_ID= ? ");
            statement.setInt(1, new Integer(itemId));
            ResultSet rs = statement.executeQuery();

            if (rs.next()) {
                Blob blob = rs.getBlob("IMAGE");

                BufferedInputStream in =
                    new BufferedInputStream(blob.getBinaryStream());
                int b;
                byte[] buffer = new byte[10240];

                while ((b = in.read(buffer, 0, 10240)) != -1) {
                    os.write(buffer, 0, b);
                }
                os.close();

            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (conn != null) {

                    conn.close();
                }

            } catch (SQLException sqle) {
                sqle.printStackTrace();

            }

        }*/
      
    }

   }


Besides hard coding the database connection string and the SQL query too, using doGet() instead of init() to setup a database connection and destroy() to close it, is not widely considered a good idea. Thus, a newer version of the servlet code  will be most welcome, due to performance reasons as well. Presenting that code would go beyond the scope of such a post, so I am turning once again to the Oracle experts mentioned above for another alternative solution!

References

http://tompeez.wordpress.com/2011/12/16/jdev11-1-2-1-0-handling-imagesfiles-in-adf-part-3/
http://www.baigzeeshan.com/2010/09/store-images-in-blob-in-oracle-adf.html
http://ranajitsahoo.blogspot.gr/2008/04/how-to-display-content-of-blob-column.html
http://www.javaranch.com/journal/200601/JDBCConnectionPooling.html