Electronic Business: Concepts, Methodologies, Tools, and Applications (4-Volumes) P20

Linking Businesses for Competitive Advantage $JOHWVZLWKSUHGH¿QHGIXQFWLRQVEXWZLWKRXW the ability to modify their behavior dynamically may be too limited for mediating e-commerce applications properly. They cannot switch roles or adjust their behavior to participate in dynamically formed partnerships. For Aglets to participate in such relationships, a complex and sophisticated G\QDPLF EHKDYLRU PRGL¿FDWLRQ infrastructure has to be developed on top of the standard Aglet services. Turning Aglet cooperation from conversa-tion level to process level could be a solution. In general, businesses collaborate following certain UXOHVVXFKDV³LI\RXVHQGPHDSULFHUHTXHVWWKHQ ,ZLOOVHQG\RXDTXRWH´DQG³LIWKHTXRWH,VHQW you is acceptable, then you will send me an order.” These rules include sequences of steps to form a business process. Such business collaboration usually involves multiple Aglets, each responsible for managing or performing certain tasks that contribute to the process. Adding inter-enterprise cooperative process management capability into agent-based systems is critical for these business collaborations. HP Web Services started from the beginning with the vision of dynamic brokering. Again, SFS allows e-services to dynamically discover and negotiate with each other and compose themselves into more complex services. This creates an open-service model, allowing all kinds of digital functionality to be delivered through a common set of APIs. SFS presents a uniform service abstraction and mediated access. New service types and semantics can be dynamically modeled using the common service representa-tion of an HP Web Services resource. However, that requires all parties to comply with HP Web Services’ service representation. ARCHITECTURE OF THE CROSS-PLATFORM BRIDGE As already mentioned, the whole software system exports utility methods for collaboration between Figure 1. HP Web Services client class diagram Es peakC lient 1 Object * 1 1 1 1 * MessageDialog 1 BridgeGUI 1 4 Properties 1 Ev ent * 1 ES Publisher 2 Result ResultSet TextField 2 1 1 ES Connection 1 1 1 1 1 ConnectionUtil 1 2 1 1 ESS ubscriber 1 * MessageDialog Ev ent 1 Object 1 1 1 1 * SubscriberImpl ES ListenerIntf 1 124 Linking Businesses for Competitive Advantage HP Web Services’ and Aglets’ applications. All functionalities can be accessed independently and are designed in a highly modular way. The important implication of the bridge is that it pro-vides a means for mobile agent applications to port from one platform to another, thus enlarging potential applications. The whole software can be partitioned into three subsystems, each operating in different environments: HP Web Services Client Software The HP Web Services Client subsystem operates in a pure HP Web Services environment. Only the standard HP Web Services components and FRQ¿JXUDWLRQVDUHQHHGHGLQWKHVDPHZD\DVWKH\ are required for HP Web Services legacy applica-tions. The environment includes a Client HP Web Services Core, where the HP Web Services Client software connects to and runs on top of it. The main purpose of this system is to provide access for external HP Web Services legacy applications to the collaboration functionalities provided by the Bridge Manager system. Aglet Client Software The Aglet Client software is the Aglet-side corre-spondent to the HP Web Services Client software. It operates from inside a Client Tahiti Server and exports a graphical user interface, as well as software interfaces to Aglet legacy applications. $JDLQRQO\PLQLPDO$JOHWFRQ¿JXUDWLRQLVUH-quired. This system mainly serves as a gateway for Aglets to deploy the Bridge Manager’s collabora-tion services, similarly as the HP Web Services Client software does for HP Web Services. Bridge Manager System The Bridge Manager consists of both a Bridge HP Web Services Core and Bridge Tahiti Server. This combined unit allows collaboration between any HP Web Services and Aglet environment. The operating system hosting this entity needs to KDYHERWKWKHFRQ¿JXUDWLRQUHTXLUHGIRUWKH+3 :HE6HUYLFHVHQYLURQPHQWDQGWKHFRQ¿JXUDWLRQ required for the Tahiti Server and Aglets environ-ment. The HP Web Services side of the Bridge Manager mainly handles intercommunication and collaboration with HP Web Services legacy Figure 2. Aglet client class diagram Ev ent Aglet MessageDialog TextField 1 1 Object 1 * 4 BridgeGUI 1 Message 1 1 1 * 1 AgletProxy 1 * 1 1 AgletClient * 1 1 Properties 1 FileInputStream MobilityListener 1 Aglet 1 MessengerAglet 1 MessageDialog * 125 Linking Businesses for Competitive Advantage Figure 3. Bridge manager class diagram FileInputStream 1 Message 1 * 1 BridgeM anager 1 Properties Aglet 1 1 Object * 1 1 1 1 * MessageDialog 1 BridgeGUI 1 4 Properties Ev ent 2 Result TextField 1 1 ES Connection 1 * 1 ES Publisher 1 1 1 1 1 ConnectionUtil 1 2 ResultSet 2 1 1 ESS ubscriber 1 * MessageDialog Message 1 1 Ev ent 1 1 Object 1 * 1 AgletProxy 1 * 1 1 1 1 SubscriberImpl * ES ListenerIntf FileInputStream 1 1 1 Properties 1 Tokenizer MobilityListener 1 Aglet 1 MessengerAglet 1 MessageDialog * applications, whereas the Tahiti Server side at-tends to Aglets legacy applications. There can be many instances of HP Web Ser-vices Client systems and Aglet Client systems. Their number is mainly limited by hardware resources and network conditions. Additionally, there can also be many instances of Bridge Man-ager systems. They can be hosted on the same physical machine or in a distributed environment. Collaboration between all those entities will still be maintained, and they can form different com- munities of collaboration. Multiple memberships in different communities are also possible as dynamic entries and leaves. DESIGN PRINCIPLES FOR THE BRIDGE BETWEEN AGLETS AND HP WEB SERVICES The following sections elaborate on methodolo-gies and general design principles that have to 126 Linking Businesses for Competitive Advantage Figure 4. Event distributor class diagram discover services, retrieve a stub object and then invoke the services. These are typically synchro- Event 1 1 Object * 1 ES Distributor Result 1 1 ResultSet 1 nous methods, with calls to methods producing results, which the client will wait on. The XML model, on the other hand, is a fundamentally asynchronous, document-based interface. Services are described not by a set of 1 1 1 EspeakBridge 1 APIs but by a schema, which describes a set of XML documents that those services can under-VWDQG7R¿QGDVHUYLFHDGRFXPHQWGH¿QLQJWKH ... - tailieumienphi.vn