1 Overview
2, technical specifications for middleware
3, introduction of three mainstream middleware technology platforms
4, middleware is the basic software for realizing e-commerce
5, the trend of middleware in line with software development
I. Overview
1, the concept of middleware
With the rapid development of computer technology, a variety of applications need to be transplanted between various platforms, or a platform needs to support multiple applications and manage multiple application systems, soft, hardware platforms, and application systems. Requireability and efficient data transfer or conversion, so that the synergy of the system is guaranteed.
These, there is a need to construct a soft and hardware platform, and the software system that provides support for the upper-level application software, while the middleware is pregnant in this environment.
Since the middleware technology is in the development process, it is currently not exactly definition.
Comparative popular definitions are: Middleware is a separate system software or service program that distributed applications share resources between different technologies. The middleware is located on the client / server operating system, manages computing resources and network communication.
As can be seen from the definition of the middleware, the middleware is a class of software, not a software; middleware not only implements interconnect, but also interconnects between applications; the middleware is based on distributed processing, The network communication function is particularly emphasized in the definition.
2, middleware characteristics and advantages
Usually, the middleware should have the following features: to meet the needs of a large number of applications; run in a variety of hardware and OS platforms; support distributed computing, providing interactions with transparency across network, hardware, and OS platforms Function; support standard protocols; support standard interfaces.
Programmers use a large number of APIs provided by calling middleware to realize the communication of heterogeneous environments, enabling complex operating systems and network protocols in the heterogeneous system.
The middleware provides connection services between clients and servers that have standard program interfaces and protocols. For different operating systems and hardware platforms, they can have a variety of implementations that meet the interfaces and protocol specifications.
Since the standard interface is important for mutual transplantability and standard protocols for interoperability, middleware has become a major part of many standardized work. For application software development, middleware is more important than operating system and network services, the program interface provided by the middleware defines a relatively stable high-level application environment, regardless of how the bottom-level computer hardware and system software are replaced, as long as the middleware Upgrade updates and keep the interface definitions of the intermediate pieces are unchanged, and the application has almost no modification, which protects the company's major investment in application software development and maintenance.
Middleware is an independent system software or service program, distributed applications share resources between different technologies. Middleware software manages communication between client programs and databases or early application software.
Middleware plays a role in distributed customers and services, such as transaction management, load balancing, and web-based calculations.
Using these technologies help to reduce the burden of application software developers, make them more mindful when using existing hardware devices, operating systems, networks, database management systems, and object models to create distributed applications. Since the middleware can protect the investment of the company, ensure the relative stability of the application software, to achieve the application software function expansion; the simultaneous intermediate parts are largely simplified a complexity of the distributed processing environment consisting of different hardware, so it The emergence is increasingly attracting attention.
The world famous consulting agency THE STANDISH GROUP summarizes the top ten advantages of the middleware:
(1) Application development: The Standish Group analyzes the proportion of business logic programs, application logic programs and basic procedures in 100 key applications; business logic programs and application logic programs account for 30% of total programs, while The basic procedure accounted for 70%, and one of the traditional senses can save 25% to 60% of the application development fees. If the application is combined with a new generation of middleware products, the application development costs can be saved to 80%. (2) System operation: There is no application system using middleware, its initial funds and operational costs are more than double more than the application system of the same size.
(3) Development Cycle: The development of basic software is a time-consuming work. If you use standard commercial intermediates, it can shorten 50% to 75% of the development cycle.
(4) Reducing the risk of project development: Research shows that the failure rate of the key application system development project without the use of standard commercial intermediates is higher than 90%. Enterprise to develop built-in foundations
(Middleware) software is not paid, and the total expense of the project is even twice, even more than ten times.
(5) Reasonable use of funds: With standard commercial intermediates, companies can easily add new functional modules from or outside or outside of the existing or legacy system, and seamlessly collections them with the original. Relying on standard middleware, you can change your old system to change your face into a new Internet / Intranet application system.
(6) Applications: Relying on standard intermediates to combine existing applications, new applications, and purchased business components together for application collection.
(7) System maintenance: It is necessary to mention that the self-development of the base (middleware) software is to pay very high cost. In addition, the expenditure of the basic (middleware) software for self-developing is required for development costs. 15% ~ 25%, the maintenance expenses of the annual application also requires about 10% to 20% of the total cost of the project. In general, purchase of standard commercial intermediates only 15% to 20% of the maintenance fees, of course, the specific price of middleware products should be based on the quantity of the product and which manufacturer.
(8) Quality: Based on the basic (middleware) software platform based on enterprise self-construction, each additional new module is added to the foundation (middleware) software. The standard middleware is clear and specified in the interface. Standard Middleware Standardization Modules can effectively guarantee the quality of application system and reduce maintenance expenses in new and old system.
(9) Technology innovation: The frequent innovation of the company's basic (middleware) software platform is extremely difficult to achieve (not practical). To purchase standard commercial intermediates, the development and changes in technology can be assured that the middleware manufacturers will grasp the technical direction and conduct technological innovation.
(10) Increase product attraction: Different commercial intermediates offer different functional models, reasonable use, allowing your app more easily add new performance forms with new service items. From another perspective, reliable business middleware also makes the company's application system is more perfect and more.
Specifically, the middleware shields the complexity of the low-rise operating system, so that the program developers face a simple and unified development environment, reduce the complexity of the programming, and focus on their own business, do not have to be procedures Dressing in different system software, thereby greatly reduces technical burden.
The middleware brings to the application system. It is not only the development of the development, the development cycle is shortened, and the workload of the system is also reduced, and the workload of the system is also reduced, and the overall computer overall cost is reduced. The STANDISH GROUP survey shows that due to the use of middleware technology, the total construction cost of the application system can be reduced by about 50%. Today, in the development of the network economy, today, from the middleware, it is not just IT manufacturers, IT users are also the winner, and it is more grasped winners.
The middleware is a new level of basic software. Its important role is to integrate application software on different operating systems in different operating systems. It is the operating system, the database management system itself cannot be can't do with one of the overall coordination of a sky. This role of the middleware, after the continuous development, making it used in the application software, saving a lot of manpower, financial investment. 3, middleware application field and classification
With the development of computer software technology, middleware technology has also matured, and there are different levels, different types of middleware products. The middleware can be divided into six categories according to the Idc classification method. Data Access Middleware, Remote Process Calling Middleware, Message Middleware, Trading Middleware, Object Middleware, etc.
Data Access Middleware: It is an intermediate member to establish a data application resource interoperability, and the database implementation of the joint or file system implementation of the intercourse;
Remote Procedure Call Middleware: Through this remote process call mechanism, programmers write client applications, which can call the procedure on the remote server;
Message Middleware: Used to block the characteristics between various platforms and protocols, communicate with each other, implement the cooperation between applications;
Trading Middleware: A environmental platform for ensuring transaction integrity and data integrity in distribution and heterogeneous environments;
Object Middleware: In distribution, heterogeneous network computing environments, various distribution objects can be organically combined, complete the fast integration of the system, and implement object reuse.
At present, many manufacturers at home and abroad have developed their middleware products, including the world's largest independent middleware manufacturer, BEA, as IBM, Oracle and Microsoft, HP, Sun, etc. have also been involved in e-commerce middleware. .
Object-oriented middleware is the product of object technology and distributed computational development. The industry generally believes that object-oriented is the mainstream direction of future intermediate parts. It provides a communication mechanism that transmits object requests in transparent distribution computing environments. And these objects can be located local or remote machines.
The object-oriented standard is originally only one, that is, CORBA (public object requesting agency architecture), which is developed by many manufacturers including BEA, IBM, Oracle, Sun and Sybase, etc., which form a huge CORBA alliance forces. . Later, Sun launched an enterprise JavaBeans (EJB), which has improved CORBA with the program model of yourself. The appearance of Microsoft COM (Component Object Model, Component Object Model) makes more standards in the object-oriented middleware market, so that object-oriented middleware products actually form two standards, one is Microsoft COM, one is Javabeans. From a macro look, the middleware can be divided into 3 categories:
* Data classes: Used for data access, utilization, and value, such intermediates are used to build data-centric applications
* Treatment class: Connect the various applications or processes distributed on the network node to form a unified distributed application.
* Distributed components: support component applications, the development direction of future applications, currently in competition.
In order to be clearer, we subdivided the middleware into 12 kinds, as follows:
Middleware classification table:
Serial number
species
Unexpected
product
1
Database system product
Manage database connections, abstract network protocols. Generally provided by a database vendor or a middleware that supports multi-database libraries
Database vendors have strong product functions and better performance. The products independent of the database manufacturers have decreased in the use of multi-database environments.
Oracle Net8
Sybase Netlib, Protocol Services INTERSOLV Sequelink Client
2
Data stock APIS
Supports programming for data inventory, you can use stored procedures. The OO database is an OO programming language, such as Java / C provides an access to ODMG interface database vendors to support access to all databases, and thus suitable for writing OLTP applications. And ODBC or JDBC is more suitable for the environment of multi-database
IBM DB2 CLI
Oracle Net8, Call Interface
Microsoft ODBC, OLE DB
ODI's PSE
3
Data migration, conversion
Used for data deployment, conversion, information value added. Often as part of the data warehouse solution
Make completely different packets and legacy applications work together, but it is necessary to establish features such as time, data, and elements, and resources.
IBM Data Propagator
Sybase Replication Server
Platinum Infopump
D2K Tapestry
4
Bottom Synchronization Service (RPC)
Make the process of calling the remote and the same locally. The calling process is in a blocking state before the process is called until the process is not completed.
Point but code is abstract, only in all Server is online. Not suitable for mobile or Internet applications
DCE-RPC (Microsoft uses it in DOM)
Borland Entera
NOBLENET RPC
5
Simple asynchronous message
Simple is the message transmission and reception, sometimes expanded to reliable delivery, intelligent route and name service
It is very useful for applications that require high performance asynchronous communications. But all Server is online
Peerlogic Pipes
MOMENTUM XIPC
Dongfang Technology Tonglink
6
Application level message queue
It is the extension of simple message middleware, adding queues, offline processing power, reliable delivery and release subscriptions.
Make distributed processing can be suitably suitable for emissions, event-driven, etc., suitable for e-commerce, mobile users, workflows, or other environments.
Tibco Rendenous
IBM MQ Series
MS Message Queue
Level8 Falconmq
Dongfang Technology Tonglink / q
Tsinghua North America TH - MT
Seduce
Application coordinator
Usually an extension of the application level message queue, adding many tools to establish integration applications for event services
Effectively saving integrated time, especially for application packages or workflow products
Vitria Velociti
Active Software, ActiveWeb
Oberon ProSperp
Neon neonet
TSI Mercator
8
COM / DNA
Microsoft's distributed component platform makes enterprise applications more expandable and manageable
From COM development, it is the mainstream product in the component market. There is still a need to add reliability for enterprise applications.
MS, COM, DCOM, COM
MS MTS
Message Queue Server
ActiveDirectory (FUTURE)
9
CORBA platform
OMG standard, connect distributed objects into a logically unified whole through ORB
The standard of industrial organization can be implemented in different ways to improve interoperability
Iona ORBIX
Borland / Visigenic, Visibroker
IBM ComponentBroker
BEA ICEBERG
Dongfang Technology Tongbroker
10
Transaction monitor
Server and API for developing real-time OLTP applications for managing transactions, sharing resources
It has proven to be an effective means of building an OLTP application. Usually non-objective, with unique and complex APIs
BEA Tuxedo
IBM TX series
Dongfang Technology TonGeasy
Tsinghua North America Javast
11
application server
Provide the complete environment of the server components for Internet, intranet, and other distributed components
Similar to the transaction monitor, just object-oriented, supporting components, standard API
NetDynamics
IBM COMPONT - BROKER
Netscape kiva
Oracle app. Ser
Dongfang Technology TongWeb
Tsinghua North American WebFirst
12
Workflow / application integration
Hagi, combine workflow and application development technology such as messages and distributed components
To make the processing easy and automatic and components, Script applications, workflow is combined, and integrate documents and emails
LSS Flowman
IBM Flowmark
Action, Technologies, Actionworks
Vitria Business Agiliti
Second, the technical specifications of middleware
1, DCE system
DCE is an abbreviation of the Distrbute Computing Environment distributed computing environment, which is developed by Open Software Fondation, and now this organization is called Open Group.
The DCE consists of multiple components that work together, they are: Remote Process Call (RPC), Local and Global Directory Services (CDS and GDS), Security Services, DCE Threads, Distributed Clock Services (DTS), and Distributed Files Service (DFC). Threads, RPCs, CDS, security services, and DTS components are often a security core, and is a component necessary for any DCE environment, and DTS is optional. In the DCE environment, management tools for managing these components are also included.
DCE is called a middleware or a technology that has its ability to exist independently, but is bundled in a vendor operating system or is integrated by a third party supplier.
2, DTP model
The DTP model is a software structure proposed by the X / Open organization, which allows multiple applications to share resources provided by multiple resource managers and have the ability to coordinate global things.
X / Open is an independent, global open system organization, which has been supported by most of the world's largest information system suppliers, which is fundamentally, anything to standardize the open system, from the viewpoint of calculation How to make users get greater benefits.
The X / Open's DTP model consists of 5 basic modules:
Application (AP): The boundary used to define things and determine the action that makes up the operation.
Resource Manager (RM): If a database or file system is used to access files.
Listing Manager (TP): Assign things identified, monitoring the processing of things and is responsible for the completion of things and the recovery of coordination of things failure.
Communication Explorer (CRM): Controls communication between or between the two matters or two matters.
Communication procedures: Between distributed applications, provide underlying communication services between communication resource managers.
The X / Open model between the five modules defines the interface specifications between such modules and modules:
Application-Explorer has existed some X / Open specifications, such as SQL and ISAM; TX interfaces are defined between the application - Listing Manager; between the Trading Manager - Resource Manager The XA interface is defined; there is three interfaces between the Trading Manager - Communication Explorer; there is 3 interfaces between the application-Communication Explorer: TXRPC, XATMI and CPI-C; in communication resource management The XAP-TP interface is provided between the underlying communication protocol provided by the operating system.
3, CORBA
Corba is an abbreviation of Common Object Request Broker Architecture. It is abbreviated as a public object request agency structure. It is developed by the International Object Management Organization OMG. This organization is an international organization. It is founded in 1989. It has now included in manufacturer and software developers. More than 800 members, the purpose is to provide a public framework for the development of application software in distribution and constructed computer environments, so that the development of the software is object-oriented and can be reproducible, portable, and operability. See Section III below for other functions of CORBA. 4, J2EE
J2EE is an abbreviation for Java 2 Platform Enterprise Edition, a multi-layer application mode structure system. The entire specification is proposed by Sun Company, which separates the business logic from the system service function and the user interface, placed between the two layers of the client layer and the application infrastructure, is the most widely used web-oriented application. System structure specification. See Section III below for other functions of J2EE.
