RE: Addition to struts.utils packes

[Alan Mehio <al...@yahoo.co.uk>]

Thanks. I think it is useful since the user session size needs to be
controlled in some big portal applications. It would be nice to include it
into the struts utility package





> -----Original Message-----
> From: fzlists@omnytex.com [mailto:fzlists@omnytex.com]
> Sent: 21 December 2004 21:22
> To: dev@struts.apache.org
> Subject: Addition to struts.utils packes
>
>
> I recently had a need to determine the size of a user's current
> session, and I didn't find any available option, so I rolled my
> own.  If I in fact didn't miss something and this really doesn't
> exist somewhere already, then I'd like to offer it up for
> inclusion in the struts.utils package.  I can see this being a
> new SessionUtils class.
>
> I wasn't sure how logging should be handled, so I converted what
> I use over to simple System.out's.  Obviously that needs to be
> changed, but for now it's fine.  It will only work with
> serializable objects in session, and it probably has other
> shortcomings that I'm not aware of.
>
> In any case, just calling getSessionSize(), passing it a valid
> HTTPSession object, and off you go.  As written, it dumps
> information to stdout about all the objects encountered, but it
> might be sufficient to remove all that and just let it return a
> final value.  I tend to prefer more information though.
>
> Here you go, hope it's useful...
>
>   /**
>    * This method is used to get the total size of a current,
> valid HTTPSession
>    * object it is passed.
>    *
>    * @param   session  A valid HTTPSession object
>    * @return           The total size of session in bytes
>    */
>   public static int getSessionSize(HttpSession session) {
>
>     System.out.println("!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");
>     System.out.println("!!!!!!!!!! getSessionSize() !!!!!!!!!!");
>   	Enumeration enum = session.getAttributeNames();
> 	  String      name = null;
>     Object      obj  = null;
>     String      serialOut;
>     String      SIZE_DELIMITER = "size=";
>     int         sizeIndex;
>     int         objSize;
>     int         totalSize = 0;
> 	  while (enum.hasMoreElements()) {
> 	    name      = (String)enum.nextElement();
> 	    obj       = session.getAttribute(name);
>       serialOut = AppHelpers.serializiableTest(obj);
>       if ((sizeIndex = serialOut.lastIndexOf(SIZE_DELIMITER)) > 0) {
>         objSize = Integer.parseInt(serialOut.substring(sizeIndex
> + SIZE_DELIMITER.length(), serialOut.lastIndexOf(')')));
>         totalSize += objSize;
>       }
> 	    System.out.println("Attribute " + name + " - " + serialOut);
> 	  }
>     System.out.println("Current total session size = " + totalSize);
>     System.out.println("!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");
>     return totalSize;
>
>   }
>
>
>   /**
>    * This method is used by the getSessionSize() method to determine if a
>    * given object is serializable.
>    *
>    * @param   Object  The object to test
>    * @return  String  A response string detailing the outcome of the test
>    */
>   private static String serializiableTest(Object obj) {
>
>     String ans = "ok";
>     if (obj == null) {
>       return "Object is null";
>     } else {
>       try {
>         ByteArrayOutputStream bastream = new ByteArrayOutputStream();
>         ObjectOutputStream p = new ObjectOutputStream(bastream);
>         p.writeObject(obj);
>         ans = "OK (size=" + bastream.size() + ")";
>       } catch (NotSerializableException ex) {
>         Field[] fields = obj.getClass().getDeclaredFields();
>         ans = "NOT SERIALIZABLE (fields=" + fields + ")";
>         ex.printStackTrace();
>         Object fldObj = null;
>         if (fields != null && (fields.length != 0)) {
>           StringBuffer sb = new StringBuffer("\n" + ans + "[");
>           for (int i = 0; i < fields.length; i++) {
>             sb.append(fields[i].getName());
>             try {
>               if (obj != null) {
>                 fldObj = getFieldWithPrivilege(fields[i], obj);
>               }
>               sb.append("::");
>               if (fldObj == null) {
>                 sb.append("<field null>");
>               } else {
>                 sb.append(serializiableTest(fldObj));
>               }
>             } catch (IllegalArgumentException aex) {
>               sb.append("::");
>               sb.append("ILLEGAL ARGUMENT EXCEPTION");
>             }
>             if (i != fields.length - 1) {
>               sb.append('\n');
>             }
>           }
>           sb.append("]");
>           ans = sb.toString();
>         }
>       } catch (Exception ex) {
>         ans = "EXCEPTION: " + ex.getMessage();
>       }
>     }
>     return obj.getClass().getName() + " is " + ans;
>
>   }
>
>
>   /**
>    * This method is used by the serializiableTest() method to get the
>    * needed priveleges on a given field of a given object needed to
>    * perform the serializable test.
>    *
>    * @param   Field   The field to get priveleges on
>               Object  The object to test
>    * @return  Object  A Priveleged reference to the field essentially
>    */
>   private static Object getFieldWithPrivilege(Field fld, Object obj) {
>
>     final Object obj2 = obj;
>     final Field  fld2 = fld;
>     return AccessController.doPrivileged(
>       new PrivilegedAction() {
>         public Object run() {
>           try {
>             return fld2.get(obj2);
>           } catch (IllegalAccessException ex) {
>             ex.printStackTrace();
>             return null;
>           }
>         }
>       }
>     );
>
>   } // End getFieldWithPrivilege()
>


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