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Connectors and APIs

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:

  • Microsoft .NET

    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.

  • Java

    The Java connector is compatible with EJB and CORBA frameworks.

  • JDBC

    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.

  • COM

    Use the COM connector to create ASP, Visual Basic, VBScript, and C++ applications that integrate host data into Web or client/server applications.

  • C

    Use the C connector to create applications that integrate host data into Web applications or client/server applications on UNIX and Windows platforms.

Examples and Documentation

Along with a complete description of the interface, example programs are available. In the online help under the Java, COM, C, and COM Connector nodes, click Examples. You can use the Web Builder tool to create Java projects, based on the "demo" models provided with Verastream Host Integrator, and then examine the Java code in your projects to see how the Java connector works.

There are also event handler examples for both .NET and Java; open <install directory>\Verastream\HostIntegrator\examples. This folder also contains an example of Verastream Host Integrator C API.

API documentation is provided for the Java, C, JDBC, 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.

See Accessing Host Data.

Additional Host Integrator APIs

There are references for two additional Host Integrator APIs available:

  • Event Handling API

    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.

  • Model Variable Management API

    The com.wrq.vhi.sconfig package contains methods for managing model variable lists on Host Integrator servers. See Working with Model Variable Lists, in the Host Integrator Administrative Console, under How to Use Host Integrator for information on creating model variables and model variable lists.