VHI connectors are collections of runtime objects, APIs, and libraries that will help you develop efficient client/server and Web applications that integrate host data, by means of the Host Integrator server, into various development environments.
Client/server and Web applications access data from, and input data to, a host application, by making calls to Host Integrator Server using a Host Integrator API. Upon receiving a client request, Host Integrator server instantiates a session with the host system using the logic stored in the model. Host Integrator Server navigates through the host application, fetches the requested data, and returns it to the client in a form native to the client development environment.
There are connectors available for a variety of programming languages and environments:
The .NET Connector creates Microsoft .NET applications that integrate host data into client/server and Web applications. Microsoft .NET is an XML Web services platform that developers can use to create programs that transcend device boundaries and fully harness the connectivity of the Internet.
Use the J2EE Connector to create Java applications that integrate host data into J2EE application servers.
The Java connector is compatible with EJB and CORBA frameworks.
The JDBC connector provides an industry standard Structured Query Language (SQL) interface to Host Integrator servers. Although the server is not a relational base system, the Table feature provides access to the host application in a way that simulates traditional sets of relational database tables. The JDBC connector works only with the table layer of the modeling process; access to model layer or terminal layer interfaces is not provided.
Use the COM connector to create ASP, Visual Basic, VBScript, and C++ applications that integrate host data into Web or client/server applications.
Use the C connector to create applications that integrate host data into Web applications or client/server applications on UNIX and Windows platforms.
Along with a complete description of the interface, each connector contains one or more example programs. Each example program connects to a demonstration host application model and performs some simple tasks to demonstrate programmatically how to connect to a host application model, start and end a host session, and manage host application data.
API documentation is provided for the Java, C, and .NET connectors. A Visual Basic API reference is provided for the COM connector, though COM supports additional programming tools, including C++, JScript, and VBScript. A J2EE Connector Architecture (JCA) Resource Adapter provides managed and secure host access for J2EE applications.
There are references for two additional Host Integrator APIs available:
Event handling extends the capabilities of models by letting you define specific events that suspend the interpretation of a model and turn control over to user-supplied procedural code.
The com.wrq.vhi.sconfig package contains methods for managing model variable lists on Host Integrator servers. See Working with Model Variables, under Server Reference | How to Work with Servers for information on creating model variables and model variable lists.
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