Legacy System Integration Technology for Legacy Application Utilization from Distributed Object Environment

Transcription

1 Legacy System Integration Technology for Legacy Application Utilization from Distributed Object Environment 284 Legacy System Integration Technology for Legacy Application Utilization from Distributed Object Environment Masaichiro Yoshioka Takuma Sudo Akihiro Yoshikawa Keiichi Sakata OVERVIEW: New enterprise information system is requested to be flexible and efficient in order to cope with rapidly changing business environments and advancement of services. For this reason, the Internet technology has been applied to the enterprise information system, and new information technologies such as distributed object technology, Java* 1 and ActiveX* 2 are beginning to be introduced. There also exist many properties in enterprise information systems, such as the application programs or legacy data, which have been developed for a long time. In order to unite these properties with new information technologies, legacy system technology using distributed object technology was developed. With this technology, processes and data such as on-line processing, batch processing, and databases on the existing mainframe systems including can be utilized from the distributed object environment. Development of new applications utilizing the existing property and construction of new and flexible value-added systems integrated with the commercial software of a distributed object base thereby become possible. INTRODUCTION NEW enterprise information systems need to be flexible and efficient in order to cope with rapidly changing business environments and progress in services. For this reason, Internet technology is being applied to enterprise information systems, and new information technologies, such as distributed object technology, Java and ActiveX are beginning to be introduced. It has become important to unite the properties built into existing application programs with new information technology, and develop more flexible and extensible enterprise information systems. The legacy system technology assists in this unification. It enables the existing property freely utilized from the new environment through flexible connections with the distributed object technology. Using this technology, the existing programs and data can be used independent of the distributed object environment, without any significant change. Value-added services by with other systems can thereby be provided quickly and easily, employing existing property to the maximum efficiency. This report discusses the positioning of legacy system technology, its architecture, and (Virtual-Storage Operating System 3) wrapping products. SYSTEM INTEGRATION IN NETWORK OBJECTPLAZA Network Objectplaza 1) is the architecture for the next-generation information system constructed on the basis of the distributed object environment which Hitachi advocates. As a distributed object base, Network Objectplaza consists of TPBroker containing ORB (Object Request Broker), CORBA (Common Object Request Broker Architecture)* 3 services, a system base, a development environment, an operation management, and application frameworks. Here, the system base enables the construction of systems, in which not only C++ and Java applications but also various existing applications or commercial packages can be accessed *1: Java and all Java-based trademarks and logos are trademarks or registered trademarks of Sun Microsystems, Inc. in the United States and other countries. *2: ActiveX is a trademark of Microsoft Corp. in the U.S. and other countries. *3: CORBA is a standard for distributed objects being developed by the Object Management Group (OMG).

2 Hitachi Review Vol. 47 (1998), No HTTP Development environment framework Applications framework System management System base Client Legacy system ActiveX Secure framework Distributed object base ORB + CORBA service HiRDB Java HTTP: hypertext transfer protocol : application program HiRDB: highly scalable relational database Fig. 1 Network Ojectplaza. Network Objectplaza is a distributed object base information systems architecture. In this architecture, the system base is a core function which integrates servers and clients into a distributed object environment. freely from clients, such as a web browser, Java, ActiveX, etc. (Fig. 1). One reason that Network Objectplaza is built on the CORBA environment is that CORBA provides interoperability for achieving a variety of system s. The most notable one now is the of an on-line program or a batch program on. Moreover, for the system in heterogeneous environment, the tools for making various systems and applications cooperate flexibly, utilization technology and SI (system ) technology are also important. ARCHITECTURE OF LEGACY SYSTEM INTEGRATION Wrapping Wrapping is the technology that provides a new interface using a conversion program (), without changing the interface of the existing software. The system, conventionally used only in a specific environment, can in this way be used in a new environment. Specifically, we call this use in a new environment Legacy System Wrapping, in which the existing mainframe system is wrapped. If we use this wrapping technology in a distributed object environment, the program and data of the existing system can be treated as an object, and can be cooperated with other objects easily (Fig. 2). Classification of Wrapping Methods The objects of wrapping are on-line systems, batch processing, and database systems on a mainframe. Although the interface of each legacy system differs, the will absorb the difference, and show those properties as objects with the unified interface as a distributed object (Fig. 3). In the case of on-line system wrapping, there are several methods for connection with a legacy system. The simplest method is to use a which carries out the same operation as a terminal (screen in Fig. 3). By this method, the configuration of the mainframe does not need to be changed at all.

3 Legacy System Integration Technology for Legacy Application Utilization from Distributed Object Environment 286 Network Objectplaza Legacy system wrapping DCCM3 TMS-4V On-line On-line system batch XDM HiRDB Application System base Web page generation HTTP IIOP Database DB Java Distributed object base Web browser Internet intranet ActiveX Java ActiveX IIOP: Internet inter-orb (object request brocker) protocol DCCM3: Data Communication and Control Manager3 TMS-4V: Transaction Management System 4V XDM: extensible data manager Fig. 2 Legacy System Integration Technology. Legacy system technology converts the legacy system interface into the distributed object interface. Accessed from a web browser or Java application, the conventional properties, such as an on-line system, batch processing, and database, etc., will be more advantageously used, and now values will be added. Conversely, when changing a legacy system for maintenance, for example, the position of the input domain in a screen is moved 1 line, and a corresponding correction is also needed for the side. This is because a screen recognizes the data by the coordinates on the display screen. The logic interface wraps the inputoutput data of an on-line system using the more logical connection than the screen. Since it does not use a screen interface, efficiency is better and is not influenced by the layout of a screen. Although the form of the input-output data differs for each application, since definition data describing this form usually exists, the can create definition data for wrapping using this definition. Furthermore, the business logic takes the interface structure for each application into consideration. The concrete method of wrapping depends on each application. For example, the business logic can automatically manage legacy input- Mainframe Online processing (Application specific) logic Logical messages Logical interface Screen ORB DB processing Screen control data ODBC, etc. Remote batch interface New New New New New ODBC (Open Database Connectivity) is Microsoft s strategic interface for accessing databases. Fig. 3 Classification of On-Line System Wrapping. An enterprise application on a mainframe system is wrapped into an object form. On-line system wrapping has several connection methods.

4 Hitachi Review Vol. 47 (1998), No output data which use two or more screens to be acquired only by 1 call from a client. processing can be performed using a remote batch interface, and the result can also be acquired by the file transmission. Although it is not as real-time as an on-line operation, it can be used in a way like start first when required and see the result after taking for a while. Moreover, a database can also be directly controlled by the wrapping using a database access interface such as ODBC. It will be fit for a simple operation like reference. (to client PC) ORB HTTP New application New application WWW connection services Wrapper Definition file Reading definition file Session management Scenario execution State surveillance Error handling Connection gateway Architecture of On-Line Wrapping Since originally an on-line system is connected and used by terminals, it is premised on the architecture peculiar to terminals, such as specific communication sessions. For this reason, a needs to have a functionality to control these interfaces. The architecture of on-line wrapping using the business logic is shown in Fig. 4. Here, the definition file holds, for example, a parameter peculiar to applications, such as the name of the data item or the name of the screen. Session management manages the communication session with a legacy system, and provides the function of maintaining the session virtually. This is because, when a client uses the WWW (World Wide Web), although communication with a browser will be disconnected by every screen, a legacy system usually holds session, while continuing the operation. Scenario execution provides a function which automatically performs and controls accesses to two or more screens. State surveillance is needed in order to understand the state change of a legacy system correctly. In the case of a transition to an unexpected state, an error handling function tries to recover from that state. In addition, cooperation with the two phase commit or the recovery service, for example, is also needed in some applications. INTEGRATION WITH SYSTEM The function for treating the resource and process on as an object in a distributed object environment is called the wrapping function. Using this function, the system can cooperate with an open system easily, without greatly changing the environments on. By integrating and a distributed object environment, we can obtain advanced value-added services quickly and easily, employing the existing property with the maximum Fig. 4 Architecture of On-Line System Wrapping. On-line consists of the gateway for connecting with the on-line system, and the function controlling the accesses. efficiency. Functional Outline of Wrapping The wrapping function includes (1) on-line wrapping, (2) batch wrapping, and (3) database wrapping. The wrapping function has a file which defines its operation. The support tool to create this definition file is also provided. By using the wrapping function, we can access the resources on through the application object on servers, such as UNlX* 4 or Windows NT* 5, from the client of Windows 95* 5, for example. When using a WWW browser, web page generator (web page generation function) can be used. The web page generator calls the CORBA object from HTML (hypertext markup language), and sticks the results on a web page. It can create a web page easily from the results from access. On-Line Wrapping The on-line wrapping is a function to treat a transaction with the on-line system on as an object. XDM/DCCM3 wrapping and TMS-4V/SP wrapping are first among the on-line wrappings. Using these functions, we can change the user interface from a dumb-terminal basis to a WWW *4: UNIX is a registered trademark in the United States and other countries, licensed exclusively through X/Open Company Limited. *5: Windows and Windows NT are registered trademarks of Microsoft Corp. in the U. S. and other countries.

5 Legacy System Integration Technology for Legacy Application Utilization from Distributed Object Environment 288 Fig. 5 On-Line System Wrapping and Wrapping Outline. In on-line system wrapping and batch wrapping, a common base and individual are provided on the distributed object environment of UNIX system. Other enterprise systems Mobile clients Internet Enterprise office systems UNIX, WindowsNT server WWW server Distributed object application New Web page generator Object -base Object for DCCM3 Object for batch Distributed object base: TPBroker Definition file Object for TMS-4V/SP XM analysis support tool XDM/DCCM3 TMS-4V/SP Open job entry Online wrapping wrapping browser, or building a new system by cooperating each work which had no relation before has become possible. At this time, the existing application on needs to be changed only a little. In the definition file for on-line wrapping, the screen layout information and the screen transition information are described in scripts. (1) XDM/DCCM3 wrapping XDM/DCCM3 wrapping is the function of wrapping DCCM3 applications using the terminal screen interface, a logic interface, and message communication. As a support function of DCCM3 wrapping, there is an XM analysis support tool which creates wrapping definition file information automatically from the XM file which defines a terminal screen. (2) TMS-4V/SP wrapping TMS-4V / SP wrapping is the function of wrapping TMS-4V/SP applications using a logic interface. (3) Wrapping of other on-line systems The wrapping function of other systems, such as the on-line system on VOS1, will also be provided in the same manner. Wrapping wrapping is the function which enables the starting and execution surveillance of batch jobs from a distributed object environment. After a job is performed, the execution result is returned to the application on the distributed object side. By batch wrapping, extensive data can be processed asynchronously in a lump. It can be used when dealing with extensive data on collectively. An outline of on-line wrapping and a batch wrapping is shown in Fig. 5. Database Wrapping Database wrapping is a function for accessing abundant data on from a distributed object environment. This function is a database access tool in distributed object environment, and the distributed object applications created using PGALLERY or Visual Basic* 6 will be able to access various kinds of database, such as XDM (Extensible Data Manager), HiRDB (Highly Scalable Relational Database), Sybase SQL Anywhere* 7, and ORACLE* 8. The database is attaining performance improvement by parallel processing using multithread. Moreover, since it also corresponds to DCOM (distributed component object model), a flexible enterprise information system can be constructed. An outline of a database wrapping is shown in Fig. 6. FUTURE DEVELOPMENT (1) Expansion for target In the legacy information system of an enterprise, various systems of many vendors are connected by mainframe to personal-computer server. Hitachi had produced wrapping technology of the system *6: Visual Basic is a registered trademark of Microsoft Corp. in the U.S. and other countries. *7: Sybase SQL Anywhere is a product name of Sybase, Inc. *8: ORACLE is a registered trademark of Oracle Corporation.

6 Hitachi Review Vol. 47 (1998), No Windows NT or Windows 95 Windows NT or UNIX Client applications created using PGALLERY or Visual Basic Tables Database access ActiveX control Internet Access to legacy DBMS such as XDM/RD is possible. DBMS: database management systems CORBA interface DCOM interface Database access for ORB Distributed object base TPBroker HiRDB Sybase ORACLE Legacy DBMS such as XDM/RD Fig. 6 Database wrapping Outline. Various kinds of database can be accessed from applications in a distributed object environment. Legacy system wrapping New system UNIX server Enterprise information system Intra-enterprise Existing systems Mainframe UNIX server, etc. Other enterprise systems Inter-enterprise Mainframe, UNIX server, etc. Internet/Intranet Distributed object technology Windows NT server Consumers/ social activities : Object Fig. 7 An Enterprise Information System Using Distributed Object Technology. Globalization of an enterprise information system will be accelerated by the and consolidation of various systems using distributed object technology. first. In order to provide synthetic solutions to a customer, the target of wrapping to other mainframe systems, to conventional client server systems, and also to packaged software. (2) Correspondence to toolkit- Toolkit-Integration is a library which defines the common interface for heterogeneous system, and enables clients to access applications and data of a variety of systems using the unified interface. The wrapping products will also correspond to this toolkit-, in order to achieve with more systems. CORBA security service can be used in toolkit-. We can thereby achieve fundamental services such as encryption of communication data, access control, and obtaining the access log, and the unified login capability. (3) Expansion of system technology If we use the properties of the conventional system effectively, and cooperating with the system inside and outside, we can turn a new enterprise information system into a global system. Therefore, in the system or the system consolidation, the technology has become very important for building a highly value-added system which meets each business situation combining the various kinds

7 Legacy System Integration Technology for Legacy Application Utilization from Distributed Object Environment 290 of technology. From now on, we intend to provide and expand the technology and environments much further so that different systems can be integrated more freely by combining the and integrating the systems and packages of components (Fig. 7). CONCLUSIONS This report explains the legacy wrapping technology that utilizes existing system properties using the distributed object technology which is becoming the core technology of future enterprise information systems. We consider that the open standardization and open system/network connectivity of an enterprise information system will be increasingly accelerated with the development of information technology. On the other hand, the programs and the data property which have been built thus far have also been increasing with the expansion of business. Hitachi intends to support construction of flexible and highly value-added systems which integrate new information technology and conventional system properties. REFERENCES (1) Saito, et al: Information System for the Next Generation, Hitachi Review 47, No. 6 (1998), pp (2) T. J. Mowbray, et al: The Essential CORBA, John Wiley & Sons, Inc. (1996) ABOUT THE AUTHORS Masaichiro Yoshioka Joined Hitachi, Ltd. in 1982 and now works at the 3rd Research Department of the Systems Development Laboratory. He is currently engaged in the research and development of an open enterprise information system. Mr. Yoshioka ia a member of the Information Processing Society of Japan, ACM, and IEEE-CS, and can be reached by at yoshioka@sdl.hitachi.co.jp Takuma Sudo Joined Hitachi, Ltd. in 1989 and now works at the 4th OS Development Department of the Software Development Center. He is currently engaged in the development of base in a distributed object system. Mr. Sudo is a member of the Information Processing Society of Japan, and can be reached by at sudo@soft. hitachi. co. jp Akihiro Yoshikawa Joined Hitachi, Ltd. in 1990 amd now works at the 3rd Research Department of the Systems Development Laboratory. He is currently engaged in the research and development of an open enterprise information system. Mr. Yoshikawa ia a member of the Information Processing Society of Japan, and can be reached by e- mail at yoshika@sdl. hitachi. co. jp Keiichi Sakata Joined Hitachi, Ltd. in 1975 and now works at the 1st OS Development Department of the Software Development Center. He is currently engaged in the development of mainframe-open system. Mr. Sakata is a member of the Information Processing Society of Japan, and can be reached by at sakata_k@soft.hitachi.co. jp