|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.
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...
Aug. 28, 2016 07:00 AM EDT Reads: 2,391
With so much going on in this space you could be forgiven for thinking you were always working with yesterday’s technologies. So much change, so quickly. What do you do if you have to build a solution from the ground up that is expected to live in the field for at least 5-10 years? This is the challenge we faced when we looked to refresh our existing 10-year-old custom hardware stack to measure the fullness of trash cans and compactors.
Aug. 28, 2016 02:00 AM EDT Reads: 1,777
The emerging Internet of Everything creates tremendous new opportunities for customer engagement and business model innovation. However, enterprises must overcome a number of critical challenges to bring these new solutions to market. In his session at @ThingsExpo, Michael Martin, CTO/CIO at nfrastructure, outlined these key challenges and recommended approaches for overcoming them to achieve speed and agility in the design, development and implementation of Internet of Everything solutions wi...
Aug. 28, 2016 01:30 AM EDT Reads: 2,099
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....
Aug. 28, 2016 01:00 AM EDT Reads: 2,968
Today we can collect lots and lots of performance data. We build beautiful dashboards and even have fancy query languages to access and transform the data. Still performance data is a secret language only a couple of people understand. The more business becomes digital the more stakeholders are interested in this data including how it relates to business. Some of these people have never used a monitoring tool before. They have a question on their mind like “How is my application doing” but no id...
Aug. 28, 2016 12:15 AM EDT Reads: 1,838
The 19th International Cloud Expo has announced that its Call for Papers is open. Cloud Expo, to be held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, brings together Cloud Computing, Big Data, Internet of Things, DevOps, Digital Transformation, Microservices and WebRTC to one location. With cloud computing driving a higher percentage of enterprise IT budgets every year, it becomes increasingly important to plant your flag in this fast-expanding business opportuni...
Aug. 27, 2016 11:00 PM EDT Reads: 4,011
Identity is in everything and customers are looking to their providers to ensure the security of their identities, transactions and data. With the increased reliance on cloud-based services, service providers must build security and trust into their offerings, adding value to customers and improving the user experience. Making identity, security and privacy easy for customers provides a unique advantage over the competition.
Aug. 27, 2016 08:45 PM EDT Reads: 2,364
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...
Aug. 27, 2016 06:00 PM EDT Reads: 3,108
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.
Aug. 27, 2016 05:15 PM EDT Reads: 1,589
SYS-CON Events announced today that 910Telecom will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Housed in the classic Denver Gas & Electric Building, 910 15th St., 910Telecom is a carrier-neutral telecom hotel located in the heart of Denver. Adjacent to CenturyLink, AT&T, and Denver Main, 910Telecom offers connectivity to all major carriers, Internet service providers, Internet backbones and ...
Aug. 27, 2016 05:00 PM EDT Reads: 1,897
There is growing need for data-driven applications and the need for digital platforms to build these apps. In his session at 19th Cloud Expo, Muddu Sudhakar, VP and GM of Security & IoT at Splunk, will cover different PaaS solutions and Big Data platforms that are available to build applications. In addition, AI and machine learning are creating new requirements that developers need in the building of next-gen apps. The next-generation digital platforms have some of the past platform needs a...
Aug. 27, 2016 04:00 PM EDT Reads: 620
SYS-CON Events announced today Telecom Reseller has been named “Media Sponsor” of SYS-CON's 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Telecom Reseller reports on Unified Communications, UCaaS, BPaaS for enterprise and SMBs. They report extensively on both customer premises based solutions such as IP-PBX as well as cloud based and hosted platforms.
Aug. 27, 2016 03:15 PM EDT Reads: 795
I wanted to gather all of my Internet of Things (IOT) blogs into a single blog (that I could later use with my University of San Francisco (USF) Big Data “MBA” course). However as I started to pull these blogs together, I realized that my IOT discussion lacked a vision; it lacked an end point towards which an organization could drive their IOT envisioning, proof of value, app dev, data engineering and data science efforts. And I think that the IOT end point is really quite simple…
Aug. 27, 2016 12:45 PM EDT Reads: 2,361
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...
Aug. 27, 2016 12:30 PM EDT Reads: 3,631
Data is the fuel that drives the machine learning algorithmic engines and ultimately provides the business value. In his session at Cloud Expo, Ed Featherston, a director and senior enterprise architect at Collaborative Consulting, will discuss the key considerations around quality, volume, timeliness, and pedigree that must be dealt with in order to properly fuel that engine.
Aug. 27, 2016 10:15 AM EDT Reads: 1,933
Pulzze Systems was happy to participate in such a premier event and thankful to be receiving the winning investment and global network support from G-Startup Worldwide. It is an exciting time for Pulzze to showcase the effectiveness of innovative technologies and enable them to make the world smarter and better. The reputable contest is held to identify promising startups around the globe that are assured to change the world through their innovative products and disruptive technologies. There w...
Aug. 27, 2016 07:45 AM EDT Reads: 704
Personalization has long been the holy grail of marketing. Simply stated, communicate the most relevant offer to the right person and you will increase sales. To achieve this, you must understand the individual. Consequently, digital marketers developed many ways to gather and leverage customer information to deliver targeted experiences. In his session at @ThingsExpo, Lou Casal, Founder and Principal Consultant at Practicala, discussed how the Internet of Things (IoT) has accelerated our abil...
Aug. 27, 2016 02:30 AM EDT Reads: 2,036
Is the ongoing quest for agility in the data center forcing you to evaluate how to be a part of infrastructure automation efforts? As organizations evolve toward bimodal IT operations, they are embracing new service delivery models and leveraging virtualization to increase infrastructure agility. Therefore, the network must evolve in parallel to become equally agile. Read this essential piece of Gartner research for recommendations on achieving greater agility.
Aug. 25, 2016 05:15 PM EDT Reads: 848
SYS-CON Events announced today that Venafi, the Immune System for the Internet™ and the leading provider of Next Generation Trust Protection, will exhibit at @DevOpsSummit at 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Venafi is the Immune System for the Internet™ that protects the foundation of all cybersecurity – cryptographic keys and digital certificates – so they can’t be misused by bad guys in attacks...
Aug. 25, 2016 01:00 PM EDT Reads: 2,670
For basic one-to-one voice or video calling solutions, WebRTC has proven to be a very powerful technology. Although WebRTC’s core functionality is to provide secure, real-time p2p media streaming, leveraging native platform features and server-side components brings up new communication capabilities for web and native mobile applications, allowing for advanced multi-user use cases such as video broadcasting, conferencing, and media recording.
Aug. 25, 2016 08:45 AM EDT Reads: 2,196