Java Clipboard Image Corrupted?

I try to create an applet which will capture the Image from the clipboard and POST it to my web server. However the code below doesn't work for me for some reason.
- Getting the TransferData from clipboard
- Cast it to BufferedImage
- Convert to byet array
- upload... 



Somehow the image I get at the server side is corrupted.
Run a (not so) few test and finally got it to work.





Additional steps is:
- Cast the TransferData into Image first.
- Convert Image into BufferedImage
- Then you will get the correct image at the server side.

If anyone bump into this problem, hope this post helps.
(I still don't know why it happened ...)

Java Clipboard Copy File

package com.test;

import java.applet.Applet;
import java.awt.Toolkit;
import java.awt.datatransfer.Clipboard;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import javax.swing.BoxLayout;
import javax.swing.JButton;

public class MyApplet extends Applet {
 
 /**
  * 
  */
 private static final long serialVersionUID = 3253065390977690287L;
 Clipboard clipboard = getToolkit ().getSystemClipboard ();
 
 public MyApplet() {
  setLayout(new BoxLayout(this, BoxLayout.X_AXIS));
  
  JButton btnNewButton = new JButton("New button");
  btnNewButton.addMouseListener(new MouseAdapter() {
   @Override
   public void mouseClicked(MouseEvent arg0) {
    getContentFromClipboard();
   }
  });
  add(btnNewButton);
 }
 
 private void getContentFromClipboard() {
  for(DataFlavor dfv : clipboard.getAvailableDataFlavors()) {
   System.out.println(dfv.getHumanPresentableName() + "\t" + dfv.getMimeType() + "\t" + dfv.getRepresentationClass());
   Transferable transferable = clipboard.getContents(this);
   System.out.println(transferable.isDataFlavorSupported(DataFlavor.javaFileListFlavor));
   if(transferable.isDataFlavorSupported(DataFlavor.javaFileListFlavor)) {
    try {
     Object object = transferable.getTransferData(dfv);
     List stuff = new ArrayList();
     stuff = (List) object;
     for (File file : stuff) {
      System.out.println(file.getAbsolutePath());
      // Do whatever you want with the file
      // ...
     }
    } catch (UnsupportedFlavorException e) {
     e.printStackTrace();
    } catch (IOException e) {
     e.printStackTrace();
    }
   }
  }
 }

}

The tricky part is casting java.util.Arrays$ArrayList (object) to List (stuff).

Spring ACL with UUID

Attempt 1

1. Change acl_object_identity.object_id_identity field to varchar.
2. Start application. Expecting error.
3. App started normally (before any page call)
4. Browse page, error come up. (Yes~!)
5. java.lang.String cannot be cast to java.math.BigInteger
6. Error at existing ACL entry.

Attempt 2

1. Try insert an object with UUID as PK.
2. And this is what I'm waiting for: java.lang.NumberFormatException: For input string: "741d25fe-f281-4747-95ef-229c1ba60000"

Attempt 3

1. Create a Java Project in eclipse
2. Import from spring-security-acl-3.0.5.RELEASE-sources.jar
3. Modify (trial-and-error) BasicLookupStrategy.java and ObjectIdentityImpl.java (mostly change long to String)
4. And it works, for now...

Swing Component Data Binding

I wrote a simple class to bind value change of a component to my bean. Someone must have done it many x 10000... times before. :p
Hope it helps.
Require: common-beanutils

package com.dummy;

import java.lang.reflect.InvocationTargetException;

import javax.swing.JSpinner;
import javax.swing.event.CaretEvent;
import javax.swing.event.CaretListener;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import javax.swing.text.JTextComponent;

import org.apache.commons.beanutils.BeanUtils;

public class BeanBinder {

 public static void bind(final JSpinner jSpinner, final Object object,
   final String attribute) {
  jSpinner.addChangeListener(new ChangeListener() {

   @Override
   public void stateChanged(ChangeEvent arg0) {
    try {
     BeanUtils.setProperty(object, attribute,
       jSpinner.getValue());
     System.out.println(object);
    } catch (IllegalAccessException e) {
     e.printStackTrace();
    } catch (InvocationTargetException e) {
     e.printStackTrace();
    }
   }
  });
 }

 public static void bind(final JTextComponent textComponent,
   final Object object, final String attribute) {
  textComponent.addCaretListener(new CaretListener() {

   @Override
   public void caretUpdate(CaretEvent arg0) {
    try {
     BeanUtils.setProperty(object, attribute,
       textComponent.getText());
     System.out.println(object);
    } catch (IllegalAccessException e1) {
     e1.printStackTrace();
    } catch (InvocationTargetException e1) {
     e1.printStackTrace();
    }
   }
  });
 }

}

Usage:

Java Event Listener for Console Application

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;

public class EventListener {

 private static Map eventInstances = new HashMap();
 private static Map eventRegistry = new HashMap();
 
 /**
  * 
  * @param eventName
  * @param instance - instance of the class
  * @param method - method of the class
  */
 public static void registerEvent(String eventName, Object instance, Method method) {
  eventRegistry.put(eventName, method);
  eventInstances.put(eventName, instance);
 }
 
 public static void triggerEvent(String eventName, Object... eventData) {
  Method method = eventRegistry.get(eventName);
  Object instance = eventInstances.get(eventName);
  if(method != null) {
   try {
    method.invoke(instance, eventData);
   } catch (IllegalArgumentException e) {
    e.printStackTrace();
   } catch (IllegalAccessException e) {
    e.printStackTrace();
   } catch (InvocationTargetException e) {
    e.printStackTrace();
   }
  }
 }
 
}

Drools 5.1 Human Task Example

It has been a while seen my last post. Lately I have been working on BPMS and Drools. I try to create a simple app using Drools Flow and Human task and now have some small success.

While learning and creating my simple app, looking for example online was difficult. Try google "Drools 5.1 Human Task Example" and see what you will get. So I decide to put more example online for reference. It may not be as complete but I'll show the parts that is working.

What I try to do is like this.

I start a flow, then it will run Action 1, then the Human Task, where it need human/external interaction, then Action 2 and finish.

Action 1 and Action 2 will just print some text on the screen. (System.out.println(...))

Human Task has these properties:

The ActorId "mina" is just a value. I think (haven't try) we can either set it at design time or run time.

I use eclipse (with Drools plugin (core and task)) to create a new drools project. I end up having these libraries in the project. Can still be clean up a bit but... let's continue.

[tricky part: Error is main-1.4.jar is missing.]

Ok. now we start with a simple java class with a main function. In the class, we have:

 private static KnowledgeBase readKnowledgeBase() throws Exception {
 KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder();
 kbuilder.add(ResourceFactory.newClassPathResource("human_task_flow.bpmn"), ResourceType.BPMN2);
 return kbuilder.newKnowledgeBase();
}

In the main function,

  try {
  // load up the knowledge base
  KnowledgeBase kbase = readKnowledgeBase();
 
  EntityManagerFactory emf =
      Persistence.createEntityManagerFactory( "org.drools.task" );
  Environment env = KnowledgeBaseFactory.newEnvironment();
  env.set( EnvironmentName.ENTITY_MANAGER_FACTORY, emf );
 
  SystemEventListener systemEventListener = SystemEventListenerFactory.getSystemEventListener();
 
  TaskService taskService = new TaskService(emf, systemEventListener);
 
  TaskServiceSession taskSession = taskService.createSession();
 
  taskSession.addUser(new User("Administrator"));
  taskSession.addUser(new User("mina"));
 
  MinaTaskServer server = new MinaTaskServer( taskService );
  Thread thread = new Thread( server );
  thread.start();
 
  StatefulKnowledgeSession ksession = kbase.newStatefulKnowledgeSession();
 
  WSHumanTaskHandler handler = new WSHumanTaskHandler();
 
  ksession.getWorkItemManager().registerWorkItemHandler("Human Task", handler);
 
  KnowledgeRuntimeLogger logger = KnowledgeRuntimeLoggerFactory.newFileLogger(ksession, "test");
  // start a new process instance
  ksession.startProcess("HumanTaskSample");
 
//   ksession.fireAllRules();
 
  logger.close();
 } catch (Throwable t) {
  t.printStackTrace();
 }

Now we run the app and you will notice a lot of stuff printed out in the console. Hopefully there is no error. :p

[tricky part: You need to create the default user "Administrator", OR ELSE...]

To know what is happening, use the Drools Audit View to view the log.

You can see that Action 1 and Human Task were triggered.

At this stage, a Task is created and saved in the database. (lazy to explain how)

Now we use Human Task View (from Drools Task plugin) to lookup for the task using UserId "mina". You will see the task with Status Reserved.

You can now select the task and complete it (click the "Complete" button).

Stage 1 works, but what if I want to programmaticly complete the task? So I also written some task client code.

package com.geneoz.drools;

import java.util.List;

import org.drools.SystemEventListenerFactory;
import org.drools.task.User;
import org.drools.task.query.TaskSummary;
import org.drools.task.service.TaskClient;
import org.drools.task.service.mina.MinaTaskClientConnector;
import org.drools.task.service.mina.MinaTaskClientHandler;
import org.drools.task.service.responsehandlers.BlockingTaskOperationResponseHandler;
import org.drools.task.service.responsehandlers.BlockingTaskSummaryResponseHandler;

public class GeneozTaskClient {

public static void main(String... args) {
 TaskClient client = new TaskClient(new MinaTaskClientConnector("mina",
   new MinaTaskClientHandler(
     SystemEventListenerFactory.getSystemEventListener())));
 try {
  client.connect("127.0.0.1", 9123);
  BlockingTaskSummaryResponseHandler summaryHandler = new BlockingTaskSummaryResponseHandler();
  client.getTasksAssignedAsPotentialOwner("mina", "en-UK",
    summaryHandler);
  List tasks = summaryHandler.getResults();
  TaskSummary task = null;
  for (TaskSummary taskSummary : tasks) {
   System.out.println(taskSummary.getId() + " : "
     + taskSummary.getName());
   task = taskSummary;
  }

   if (task != null) {
   BlockingTaskOperationResponseHandler operationHandler = new BlockingTaskOperationResponseHandler();
   client.release(task.getId(), "mina", operationHandler);
   client.claim(task.getId(), "Administrator", operationHandler);
   operationHandler.waitTillDone(10000);

   operationHandler = new BlockingTaskOperationResponseHandler();
   client.start(task.getId(), "Administrator", operationHandler);
   operationHandler.waitTillDone(10000);

   operationHandler = new BlockingTaskOperationResponseHandler();
   client.complete(task.getId(), "Administrator", null, operationHandler);
   operationHandler.waitTillDone(10000);

  }

 } catch (Exception e) {
  e.printStackTrace();
 } finally {
  try {
   client.disconnect();
  } catch (Exception e) {
   e.printStackTrace();
  }
  System.exit(0);
 
 }
}
}

Some explanation:

1. Create a Mina Task Client

2. Connect to default MinaTaskServer

3. Find tasks belong to "mina"

4. Release the task (from "Reserved" state to "Ready" state) so that it can be claimed by other user.

5. Start and complete the task.

And now you will have Human Task completed and Action 2 triggered.

So this is where I am currently at for the moment. Hope to discover more stuff as I move on.

Hope this example can be helpful. Sorry for the bad English. :p

iPad Scroll with jQuery

Yeah~! I did it. After pressure from my boss, I finally get some prototype done. Please see it here.
Yes!! Yes!!! Yes!!!!