Lets explore how to find this.

• Find the pid of the application, using top or jps command
• Once you get the pid, run following command
  $ ps -L pid

We get an output as shown in the figure




ps output

The output displays all the Threads in the application along with the time spent. Find the Thread that has spent highest time in execution (Entry circled on right). Once we identify this, get the LWP ID of the Thread (Entry circled on left).

• Using jstack or visualvm, take a Thread dump.
• Convert LWP ID to Hex and search for the ID in Thread dump.

Then you can narrow down the thread which is consuming max CPU and investigate further.

Will continues to post articles about MINA, to be updated,  Subscribe in a reader

Yes, we are going to implement a SNMP trap receiver in less than 30 minutes. If you have been following my post on Apache MINA, this would be a natural extension to it. In this article, we shall bring together all our components to build the system.

 Pre-requisites:

 Please read through these articles. You can find all these posts on Apache MINA

• What is Apache MINA
• Apache MINA based Server Application Architecture
• Implementing UDP Server using Apache MINA
• Implementing SNMP4J Decoder for Apache MINA

 To execute the code, you need following jars

• mina-core-2.0.0-M1.jar
• slf4j-api-1.5.0.jar
• slf4j-log4j12-1.5.0.jar
• log4j-1.2.15.jar
• SNMP4J.jar

 I am assuming that you have read my previous posts and jumping straight to the implementations. The high level architecture is explained in the post Apache MINA based Server Application Architecture

Architecture 

Let’s understand the flow here and see what all we need to do to process a trap

• Receive the trap over UDP
• Decode the Trap
• Dump the Trap

Lets see how each of the these maps to the code we have already written

It's a now simple to understand that we have reused all the components to create the Server. Let me not write too much, and jump straight to the code J

 The Server Code

The only change that we did to the UDP Server code was to add a Protocol Codec. At line 36, we added our custom ProtocolCodecFiler. The SNMPCodecFactory return the instance of our SNMP4J codec. There is not much code and this construct is fairly simple, and explained very well in MINA’s documentation. From the main method, we just need to call the method initialize() and our trap receiver starts.

References

• http://mina.apache.org/
• http://www.snmp4j.org/

Steps to create a UDP Server using java.net API's

1. Create a Socket and listen for incoming connection
2. Process each packet in a separate thread (I hate this, unfortunately need this to have high processing rate)
3. Parse and process the request and optionally send response (Lets omit this to keep things simple)

That's it

• Our protocol is carrying Strings in UDP packet
• We shall not do any transformation on the packets received. We shall just dump the content

The Handler

 

The Handler is in its basic form. Our only method of interest is messageReceived. Since we know that we are getting "String" message without any transformation, we could easily create a new string from the bytes received. A wonderful thing to note about this API is the parameter "message". This makes the API generic enough to cater to any kind of objects. If we had used a ProtocolCodec in the chain and had transformed the byte[] into a custom Object, we would have type-casted message to that object.

That's all in the handler.

 

The Server

Lets see the main Server code

 

 

The Server is even simpler than client

We create an instance of NioDatagramAcceptor and add our custom handler to it. We then bind to the port desired. Here I have made it bind to the default port, code can be customized to bind to any port desired.

So what does 31 does. There is wonderful description of this option at http://www.unixguide.net/network/socketfaq/4.5.shtml
The main function is pretty simple. The Server is ready. You can run it, using the Client from the post Implementing UDP Client using Apache MINA

References

• http://mina.apache.org/udp-tutorial.html

Have an updated version of this writeup at http://www.ashishpaliwal.com/blog/2011/07/updating-google-calendar-with-ms-project-revisited/

I am back, as promised. Please read my earlier post Processing Microsoft Project File in Java using MPXJ.

In this post we shall take an mpp and update the Google Calendar with the task details. The question is why would anyone do that? 

Lets cook the story. A small team is working and the poor Project Manager share the Schedule with the team. The team is so busy coding that they forget to look at the dates, and the tasks they must be starting on. The poor Project Manager himself loose track unless he keeps MS Project Open on his desktop :-( A pretty common situation  

Have faced this situation and decided to organize myself and this post is outcome of that. The driving force was "Out of sight, is out of mind". So my assumption was if the team has a visual of the task dates, the chances of task slippage shall reduce a lot. 

In this post, have built upon the my previous post to create an MPP parsing function. Have tried to keep the code in simplest form, so that it can customized later to specific needs. Have created a sample Schedule for this activity and used it for the implementation. Here is how it looks.

Google Calendar updater Project Schedule

The schdule is simple, some date, and tasks with dependencies. The concept shall work for any number of tasks.

Following are the steps that we need to perform:

1. Parse the mpp file
2. Create a Calendar Service (Lets assume that the Calendar is already there, though it is possible to programmatically create the same)
3. Get All tasks from MPP, and create Calendar Entries in Google Calendar

Google Calendar Entry Creation Code

The implementation is fairly simple. We have 3 functions:

• translateTaskToCalendarEventEntry() - Converts an Task into CalendarEventEntry, which can be added to Google Calendar
• updateCalendar() - Takes input of all the Tasks from MPP, translates into CalendarEventEntry (using function translateTaskToCalendarEventEntry) and update the Calendar
• updateGoogleCalendarWithMPP() - Parses the MPP using the util function from my previous post, and calls the API above to update the Calendar.

Google Calendar API usage is described in details on Google's pages, hence won't discuss here.
To use it for yourself, replace User Name and Password at line#70, with your User Credentials. Repace the URL at Line# 71 to point to your calendar.
After running the program, this is how my Calendar looked like 

Google Calendar View

A simple way to keep track of Tasks.
 

MPXJ - MPXJ is the java library used for parsing MS Project files. The lib depends upon Apache POI package for providing the functionality. MPXJ supports all the three formats for MS Project. The details can be found at the Home Page for MPXJ provided in references section

Let's start implementing. The code to read the File is fairly simple.

Reading MS Project File in Java (Using MPXJ)

 To read an MS Project file, we use projectReaderUtility class to get the instance of a ProjectReader, based on the extension. ProjectReader is the interface implemented by the classes that can read an MS Project file in mpxj library. Once we get the instance of ProjectReader, we need to invoke read API, passing the file name to be read. The API returns an instance of ProjectFile, containing all the details in the MS Project File. 

More about ProjectFile - ProjectFile is the class in mpxj, which contains all the information about an MS Project file. It has API's to access all Task details, as well other API's to extract and manipulate other metadata.

Is that it? The basic objective of reading is done. Now we can use the provided API to iterate and create applications to suite our needs. For example, to list all the tasks, use getAllTasks(), it returns a List of Tasks. Custom logic can be applied to manipulate this list as desired, like filtering the tasks based on resources or date.

What's next?

I am working on the prototype to read the MS Project File and update the Google Calendar with Task details, based on Start Date.

References

• http://mpxj.sourceforge.net/index.html
• http://poi.apache.org/index.html

Here is the definition I have used for the Framework

"An (N)IO Framework is a library, that provides easy to use API by shielding low level complexity of IO and provides rich and reusable API's to create robust and scalable Networking Applications".

A key point here is, only complexity is reduced, the power of low level API's is still available.

Have been using Apache MINA for a while, and found some similar and powerful frameworks. The idea is to share the result of searches. I don't intent to compare them on their performances or features. The text for the frameworks have been picked from the respective websites.

• Apache MINA   - MINA (Multipurpose Infrastructure for Network Applications) is a network application framework which helps users develop high performance and high scalability network applications easily.
• xSockets - xSocket is a lightweight java nio-based server framework to build high performance, high scalable, multithreaded servers. It supports writing synchronous and asynchronous client-side applications as well as server-side applications in a very intuitive way  
• Grizzly - The Grizzly framework has been designed to help developers to take advantage of the Java™ NIO API. Grizzly goals is to help developers to build scalable and robust servers using NIO.
• Netty - Netty is a NIO client server framework which enables quick and easy development of network applications such as protocol servers and clients. It greatly simplifies and streamlines network programming such as TCP/IP socket server