|By Di Li||
|May 5, 2005 03:00 PM EDT||
A custom multithreading framework is an efficient way to improve the performance of Java applications. It uses an asynchronous parallel pattern to implement the business process. However, its traditional Java thread-based implementation shouldn't be used in applications hosted in a J2EE Application Server because the threads in that framework are beyond the control of the J2EE Container. This article will discuss an intelligent solution for implementing custom multithreading by using message-driven beans. This message-driven bean based multithreading framework enables the J2EE container to manage threads and multiple MDBs to execute the business logic in parallel.
Java multithreading makes maximum use of the CPU by keeping the processor's idle time to minimum. To avoid the overhead of creating threads on-the-fly, every J2EE application server container has a default thread pool that contains a set of execute threads. The container can borrow one of the threads from the pool, and assign it a task. Upon completion of the task, the thread goes into a wait state ready to accept another assignment. The J2EE container monitors all execute threads in that pool. Custom threads are different from execute threads. They are created and controlled by the applications rather than the container. This article will introduce a solution implementing custom multithreading in a J2EE container.
Asynchronous Parallel Design PatternThe analysis model of the custom multithreading framework is based on the concept of asynchronous parallel design pattern. The pattern combines the advantages of delegate, asynchronous, and parallel design patterns. It's a model that consists of an asynchronous interface and a business engine. The business engine is composed of multiple parallel instances of business services, and fulfills the business processes. Figure 1 shows the class diagram representing the structure of the asynchronous parallel pattern.
The client doesn't have to have knowledge of the services that the back-end business engine provides. It simply sends the requests to the delegate, which adds the incoming requests to a mediator repository and returns a result to the client. The client doesn't go into a block state waiting for a response from the back-end business engine. The repository notifies the business engine when new requests are received. The multiple parallel instances of the services in the business engine then pick up the requests from the repository and process them concurrently. Figure 2 shows sequence diagrams that illustrate typical interactions among the components of the asynchronous parallel pattern.
Our example is based on an online brokerage system. We choose to model the process of an investor placing an order that is routed to the market for execution. I simplify the business scenario so we can focus on the custom multithreading framework.
Java Thread-Based Custom Multithreading Framework (CMF)The components of a Java thread-based CMF include a Thread Pool, Worker Thread, Task Dispatcher, Task, and Task Queue. The class diagram in Figure 3 shows the solution model of a Java thread-based multithreading framework.
The Task interface represents the abstract of the business cases fulfilled in the business process. Business cases are modeled by the Java class that implements the Task interface. For example, the Trade class represents the Stock Trade in a stock trading process. The business logic for processing each business case is implemented in the ‘execute' method of each class.
The TaskFIFOQueue and the TaskDispatcher classes implement the asynchronous interface of the asynchronous parallel pattern. The TaskFIFOQueue class is designed as an intermediary repository that stores unassigned tasks. The TaskDispatcher class works as the delegate of the framework, which receives clients' requests, creates an instance of a Java class implementing Task interface for each incoming request (such as Trade class), adds a new instance to TaskFIFOQueue. The client can continue with other activities without having to wait for its request to be processed. The code snippet in Listing 1 at the end of this article shows how to add or get a task from the TaskFIFOQueue.
The business engine of the asynchronous parallel pattern is implemented by the WorkThread class and the ThreadPool class. The WorkThread class provides the threads that will process the assigned task. Each instance of the WorkThread class is a custom thread, created and controlled by the application. The Thread-Pool class serves as the central control point to manage custom threads. Using an object of the ThreadPool class to store running threads lets us allocate custom threads in a predictable way, reuse an existing thread for multiple tasks, and save time for thread instantiation and initialization. The code in Listing 2 at the end of this article demonstrates how to implement the business engine.
When the TaskDispatcher receives a request from a client, it creates an instance of a particular Task-type class, such as the Trade class, and adds the instance to the TaskFIFOQueue. The TaskFIFOQueue then notifies all waiting threads that a new task is ready to be picked up. The current active WorkerThread gets the task from the TaskFIFOQueue and starts to process the task by running the execute() method of the particular Task-type class. After the WorkThreads finishes the task, it goes into a wait state and is ready to accept the next task. The sequence diagram in Figure 4 illustrates the sample collaborations for the CMF.
Although Java thread-based CMF provides an efficient solution to improve the overall performance of Java applications, it shouldn't be used in applications hosted in the J2EE application server. Java thread-based CMF is discouraged in the J2EE applications for the following reasons.
J2EE Application Server Can't Control Custom Threads
The J2EE application server container is configured to manage all the threads in the Java Virtual Machine. The threads from the CMF won't carry the implicit context that a container normally puts on a thread. The container loses control over the custom threads created explicitly by the CMF because it's not aware of their existence.
Consequently, if a custom thread fails, the container will not be able to detect the failure and so can't recover the thread - either by reclaiming the resources occupied by the particular thread or by restarting it to complete the assigned task. The presence of unmanaged failed threads in the application server can seriously impact the stability, scalability, and performance of the application server.
Thread- Based CMF Affects the Load Balancing in the J2EE Application Cluster
Since a J2EE application server isn't aware of the custom threads in the CMF, it's also not aware of the work being done by the threads, and so won't account for the impact that the additional threads have on the overall workload of the server. This will affect the load balancing of the J2EE application cluster. It will potentially over-assign work to the server, and result in significant throughput or performance problems with the server.
The EJB 2.0 specification integrates EJB with JMS, and defines a new type of Enterprise JavaBean: Message-Driven Bean (MDB). It enables the EJB container to support the asynchronous parallel design pattern. Because the basic theories of the Java thread-based CMF don't negatively impact the application server runtime, we'll use the same analysis model to design the MDB-based CMF. For the purpose of demonstration, the MDB-based framework will be implemented and deployed on WebLogic Server 8.1.
The Internet of Things is not new. Historically, smart businesses have used its basic concept of leveraging data to drive better decision making and have capitalized on those insights to realize additional revenue opportunities. So, what has changed to make the Internet of Things one of the hottest topics in tech? In his session at @ThingsExpo, Chris Gray, Director, Embedded and Internet of Things, discussed the underlying factors that are driving the economics of intelligent systems. Discover how hardware commoditization, the ubiquitous nature of connectivity, and the emergence of Big Data a...
Dec. 21, 2014 02:00 PM EST Reads: 3,070
"BSQUARE is in the business of selling software solutions for smart connected devices. It's obvious that IoT has moved from being a technology to being a fundamental part of business, and in the last 18 months people have said let's figure out how to do it and let's put some focus on it, " explained Dave Wagstaff, VP & Chief Architect, at BSQUARE Corporation, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4-6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Dec. 21, 2014 01:00 PM EST Reads: 2,610
The major cloud platforms defy a simple, side-by-side analysis. Each of the major IaaS public-cloud platforms offers their own unique strengths and functionality. Options for on-site private cloud are diverse as well, and must be designed and deployed while taking existing legacy architecture and infrastructure into account. Then the reality is that most enterprises are embarking on a hybrid cloud strategy and programs. In this Power Panel at 15th Cloud Expo (http://www.CloudComputingExpo.com), moderated by Ashar Baig, Research Director, Cloud, at Gigaom Research, Nate Gordon, Director of T...
Dec. 21, 2014 11:30 AM EST Reads: 3,142
SYS-CON Events announced today that IDenticard will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. IDenticard™ is the security division of Brady Corp (NYSE: BRC), a $1.5 billion manufacturer of identification products. We have small-company values with the strength and stability of a major corporation. IDenticard offers local sales, support and service to our customers across the United States and Canada. Our partner network encompasses some 300 of the world's leading systems integrators and security s...
Dec. 21, 2014 10:00 AM EST Reads: 2,723
SYS-CON Events announced today that Windstream, a leading provider of advanced network and cloud communications, has been named “Silver Sponsor” of SYS-CON's 16th International Cloud Expo®, which will take place on June 9–11, 2015, at the Javits Center in New York, NY. Windstream (Nasdaq: WIN), a FORTUNE 500 and S&P 500 company, is a leading provider of advanced network communications, including cloud computing and managed services, to businesses nationwide. The company also offers broadband, phone and digital TV services to consumers primarily in rural areas.
Dec. 21, 2014 08:30 AM EST Reads: 2,941
ARMONK, N.Y., Nov. 20, 2014 /PRNewswire/ -- IBM (NYSE: IBM) today announced that it is bringing a greater level of control, security and flexibility to cloud-based application development and delivery with a single-tenant version of Bluemix, IBM's platform-as-a-service. The new platform enables developers to build ap...
Dec. 21, 2014 06:15 AM EST Reads: 3,270
The BPM world is going through some evolution or changes where traditional business process management solutions really have nowhere to go in terms of development of the road map. In this demo at 15th Cloud Expo, Kyle Hansen, Director of Professional Services at AgilePoint, shows AgilePoint’s unique approach to dealing with this market circumstance by developing a rapid application composition or development framework.
Dec. 20, 2014 11:00 PM EST Reads: 2,090
“In the past year we've seen a lot of stabilization of WebRTC. You can now use it in production with a far greater degree of certainty. A lot of the real developments in the past year have been in things like the data channel, which will enable a whole new type of application," explained Peter Dunkley, Technical Director at Acision, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Dec. 20, 2014 08:00 AM EST Reads: 2,243
DevOps Summit 2015 New York, co-located with the 16th International Cloud Expo - to be held June 9-11, 2015, at the Javits Center in New York City, NY - announces that it is now accepting Keynote Proposals. The widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is no time to wait for long development cycles that produce software that is obsolete at launch. DevOps may be disruptive, but it is essential.
Dec. 18, 2014 09:45 PM EST Reads: 2,031
"People are a lot more knowledgeable about APIs now. There are two types of people who work with APIs - IT people who want to use APIs for something internal and the product managers who want to do something outside APIs for people to connect to them," explained Roberto Medrano, Executive Vice President at SOA Software, in this SYS-CON.tv interview at Cloud Expo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Dec. 18, 2014 09:00 AM EST Reads: 2,354
Nigeria has the largest economy in Africa, at more than US$500 billion, and ranks 23rd in the world. A recent re-evaluation of Nigeria's true economic size doubled the previous estimate, and brought it well ahead of South Africa, which is a member (unlike Nigeria) of the G20 club for political as well as economic reasons. Nigeria's economy can be said to be quite diverse from one point of view, but heavily dependent on oil and gas at the same time. Oil and natural gas account for about 15% of Nigera's overall economy, but traditionally represent more than 90% of the country's exports and as...
Dec. 18, 2014 06:00 AM EST Reads: 1,392
The Internet of Things is a misnomer. That implies that everything is on the Internet, and that simply should not be - especially for things that are blurring the line between medical devices that stimulate like a pacemaker and quantified self-sensors like a pedometer or pulse tracker. The mesh of things that we manage must be segmented into zones of trust for sensing data, transmitting data, receiving command and control administrative changes, and peer-to-peer mesh messaging. In his session at @ThingsExpo, Ryan Bagnulo, Solution Architect / Software Engineer at SOA Software, focused on desi...
Dec. 17, 2014 11:15 PM EST Reads: 2,310
"At our booth we are showing how to provide trust in the Internet of Things. Trust is where everything starts to become secure and trustworthy. Now with the scaling of the Internet of Things it becomes an interesting question – I've heard numbers from 200 billion devices next year up to a trillion in the next 10 to 15 years," explained Johannes Lintzen, Vice President of Sales at Utimaco, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Dec. 17, 2014 11:00 PM EST Reads: 2,299
"For over 25 years we have been working with a lot of enterprise customers and we have seen how companies create applications. And now that we have moved to cloud computing, mobile, social and the Internet of Things, we see that the market needs a new way of creating applications," stated Jesse Shiah, CEO, President and Co-Founder of AgilePoint Inc., in this SYS-CON.tv interview at 15th Cloud Expo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Dec. 17, 2014 08:00 PM EST Reads: 2,295
SYS-CON Events announced today that Gridstore™, the leader in hyper-converged infrastructure purpose-built to optimize Microsoft workloads, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. Gridstore™ is the leader in hyper-converged infrastructure purpose-built for Microsoft workloads and designed to accelerate applications in virtualized environments. Gridstore’s hyper-converged infrastructure is the industry’s first all flash version of HyperConverged Appliances that include both compute and storag...
Dec. 17, 2014 06:30 PM EST Reads: 2,270
Today’s enterprise is being driven by disruptive competitive and human capital requirements to provide enterprise application access through not only desktops, but also mobile devices. To retrofit existing programs across all these devices using traditional programming methods is very costly and time consuming – often prohibitively so. In his session at @ThingsExpo, Jesse Shiah, CEO, President, and Co-Founder of AgilePoint Inc., discussed how you can create applications that run on all mobile devices as well as laptops and desktops using a visual drag-and-drop application – and eForms-buildi...
Dec. 17, 2014 11:45 AM EST Reads: 2,388
We certainly live in interesting technological times. And no more interesting than the current competing IoT standards for connectivity. Various standards bodies, approaches, and ecosystems are vying for mindshare and positioning for a competitive edge. It is clear that when the dust settles, we will have new protocols, evolved protocols, that will change the way we interact with devices and infrastructure. We will also have evolved web protocols, like HTTP/2, that will be changing the very core of our infrastructures. At the same time, we have old approaches made new again like micro-services...
Dec. 16, 2014 11:45 PM EST Reads: 2,279
Code Halos - aka "digital fingerprints" - are the key organizing principle to understand a) how dumb things become smart and b) how to monetize this dynamic. In his session at @ThingsExpo, Robert Brown, AVP, Center for the Future of Work at Cognizant Technology Solutions, outlined research, analysis and recommendations from his recently published book on this phenomena on the way leading edge organizations like GE and Disney are unlocking the Internet of Things opportunity and what steps your organization should be taking to position itself for the next platform of digital competition.
Dec. 15, 2014 11:45 PM EST Reads: 2,651
The 3rd International Internet of @ThingsExpo, co-located with the 16th International Cloud Expo - to be held June 9-11, 2015, at the Javits Center in New York City, NY - announces that its Call for Papers is now open. The Internet of Things (IoT) is the biggest idea since the creation of the Worldwide Web more than 20 years ago.
Dec. 15, 2014 10:30 AM EST Reads: 8,231
As the Internet of Things unfolds, mobile and wearable devices are blurring the line between physical and digital, integrating ever more closely with our interests, our routines, our daily lives. Contextual computing and smart, sensor-equipped spaces bring the potential to walk through a world that recognizes us and responds accordingly. We become continuous transmitters and receivers of data. In his session at @ThingsExpo, Andrew Bolwell, Director of Innovation for HP's Printing and Personal Systems Group, discussed how key attributes of mobile technology – touch input, sensors, social, and ...
Dec. 15, 2014 10:00 AM EST Reads: 3,355