|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.
24Notion is full-service global creative digital marketing, technology and lifestyle agency that combines strategic ideas with customized tactical execution. With a broad understand of the art of traditional marketing, new media, communications and social influence, 24Notion uniquely understands how to connect your brand strategy with the right consumer. 24Notion ranked #12 on Corporate Social Responsibility - Book of List.
Sep. 30, 2016 02:30 PM EDT Reads: 295
Just over a week ago I received a long and loud sustained applause for a presentation I delivered at this year’s Cloud Expo in Santa Clara. I was extremely pleased with the turnout and had some very good conversations with many of the attendees. Over the next few days I had many more meaningful conversations and was not only happy with the results but also learned a few new things. Here is everything I learned in those three days distilled into three short points.
Sep. 30, 2016 02:30 PM EDT Reads: 5,178
There are several IoTs: the Industrial Internet, Consumer Wearables, Wearables and Healthcare, Supply Chains, and the movement toward Smart Grids, Cities, Regions, and Nations. There are competing communications standards every step of the way, a bewildering array of sensors and devices, and an entire world of competing data analytics platforms. To some this appears to be chaos. In this power panel at @ThingsExpo, moderated by Conference Chair Roger Strukhoff, Bradley Holt, Developer Advocate a...
Sep. 30, 2016 02:30 PM EDT Reads: 2,459
The vision of a connected smart home is becoming reality with the application of integrated wireless technologies in devices and appliances. The use of standardized and TCP/IP networked wireless technologies in line-powered and battery operated sensors and controls has led to the adoption of radios in the 2.4GHz band, including Wi-Fi, BT/BLE and 802.15.4 applied ZigBee and Thread. This is driving the need for robust wireless coexistence for multiple radios to ensure throughput performance and th...
Sep. 30, 2016 02:15 PM EDT Reads: 1,720
SYS-CON Events announced today that SoftLayer, an IBM Company, has been named “Gold Sponsor” of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2016, at the Javits Center in New York, New York. SoftLayer, an IBM Company, provides cloud infrastructure as a service from a growing number of data centers and network points of presence around the world. SoftLayer’s customers range from Web startups to global enterprises.
Sep. 30, 2016 02:15 PM EDT Reads: 1,153
Major trends and emerging technologies – from virtual reality and IoT, to Big Data and algorithms – are helping organizations innovate in the digital era. However, to create real business value, IT must think beyond the ‘what’ of digital transformation to the ‘how’ to harness emerging trends, innovation and disruption. Architecture is the key that underpins and ties all these efforts together. In the digital age, it’s important to invest in architecture, extend the enterprise footprint to the cl...
Sep. 30, 2016 02:15 PM EDT Reads: 709
DevOps at Cloud Expo, taking place Nov 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 19th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. 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 dev...
Sep. 30, 2016 02:00 PM EDT Reads: 3,569
If you had a chance to enter on the ground level of the largest e-commerce market in the world – would you? China is the world’s most populated country with the second largest economy and the world’s fastest growing market. It is estimated that by 2018 the Chinese market will be reaching over $30 billion in gaming revenue alone. Admittedly for a foreign company, doing business in China can be challenging. Often changing laws, administrative regulations and the often inscrutable Chinese Interne...
Sep. 30, 2016 01:45 PM EDT Reads: 576
Adobe is changing the world though digital experiences. Adobe helps customers develop and deliver high-impact experiences that differentiate brands, build loyalty, and drive revenue across every screen, including smartphones, computers, tablets and TVs. Adobe content solutions are used daily by millions of companies worldwide-from publishers and broadcasters, to enterprises, marketing agencies and household-name brands. Building on its established design leadership, Adobe enables customers not o...
Sep. 30, 2016 01:15 PM EDT Reads: 311
Internet of @ThingsExpo, taking place November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 19th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The Internet of Things (IoT) is the most profound change in personal and enterprise IT since the creation of the Worldwide Web more than 20 years ago. All major researchers estimate there will be tens of billions devices - comp...
Sep. 30, 2016 01:15 PM EDT Reads: 5,164
Information technology is an industry that has always experienced change, and the dramatic change sweeping across the industry today could not be truthfully described as the first time we've seen such widespread change impacting customer investments. However, the rate of the change, and the potential outcomes from today's digital transformation has the distinct potential to separate the industry into two camps: Organizations that see the change coming, embrace it, and successful leverage it; and...
Sep. 30, 2016 01:15 PM EDT Reads: 1,287
Cloud computing is being adopted in one form or another by 94% of enterprises today. Tens of billions of new devices are being connected to The Internet of Things. And Big Data is driving this bus. An exponential increase is expected in the amount of information being processed, managed, analyzed, and acted upon by enterprise IT. This amazing is not part of some distant future - it is happening today. One report shows a 650% increase in enterprise data by 2020. Other estimates are even higher....
Sep. 30, 2016 01:00 PM EDT Reads: 4,235
Smart Cities are here to stay, but for their promise to be delivered, the data they produce must not be put in new siloes. In his session at @ThingsExpo, Mathias Herberts, Co-founder and CTO of Cityzen Data, will deep dive into best practices that will ensure a successful smart city journey.
Sep. 30, 2016 12:45 PM EDT Reads: 2,703
19th Cloud Expo, taking place November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud strategy. Meanwhile, 94% of enterpri...
Sep. 30, 2016 12:45 PM EDT Reads: 4,492
Businesses are struggling to manage the information flow and interactions between all of these new devices and things jumping on their network, and the apps and IT systems they control. The data businesses gather is only helpful if they can do something with it. In his session at @ThingsExpo, Chris Witeck, Principal Technology Strategist at Citrix, will discuss how different the impact of IoT will be for large businesses, expanding how IoT will allow large organizations to make their legacy ap...
Sep. 30, 2016 12:30 PM EDT Reads: 497
Why do your mobile transformations need to happen today? Mobile is the strategy that enterprise transformation centers on to drive customer engagement. In his general session at @ThingsExpo, Roger Woods, Director, Mobile Product & Strategy – Adobe Marketing Cloud, covered key IoT and mobile trends that are forcing mobile transformation, key components of a solid mobile strategy and explored how brands are effectively driving mobile change throughout the enterprise.
Sep. 30, 2016 12:30 PM EDT Reads: 2,262
From wearable activity trackers to fantasy e-sports, data and technology are transforming the way athletes train for the game and fans engage with their teams. In his session at @ThingsExpo, will present key data findings from leading sports organizations San Francisco 49ers, Orlando Magic NBA team. By utilizing data analytics these sports orgs have recognized new revenue streams, doubled its fan base and streamlined costs at its stadiums. John Paul is the CEO and Founder of VenueNext. Prior ...
Sep. 30, 2016 12:30 PM EDT Reads: 3,271
“We're a global managed hosting provider. Our core customer set is a U.S.-based customer that is looking to go global,” explained Adam Rogers, Managing Director at ANEXIA, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
Sep. 30, 2016 12:15 PM EDT Reads: 3,233
What does it look like when you have access to cloud infrastructure and platform under the same roof? Let’s talk about the different layers of Technology as a Service: who cares, what runs where, and how does it all fit together. In his session at 18th Cloud Expo, Phil Jackson, Lead Technology Evangelist at SoftLayer, an IBM company, spoke about the picture being painted by IBM Cloud and how the tools being crafted can help fill the gaps in your IT infrastructure.
Sep. 30, 2016 11:15 AM EDT Reads: 3,105
Developing software for the Internet of Things (IoT) comes with its own set of challenges. Security, privacy, and unified standards are a few key issues. In addition, each IoT product is comprised of (at least) three separate application components: the software embedded in the device, the back-end service, and the mobile application for the end user’s controls. Each component is developed by a different team, using different technologies and practices, and deployed to a different stack/target –...
Sep. 30, 2016 11:15 AM EDT Reads: 1,576