Design Tool Features

The Design Tool provides the following features to aid you in encapsulating the functionality of your host application:

Connecting to a Host

The Design Tool is capable of connecting to any one of following hosts:

Select the type of host you are connecting to in the New Model or Session Setup dialog box.

Using Models to Encapsulate a Host Application

The main feature of the Design Tool is the modeling feature, which enables a host expert to create a model of a host application. First, you connect to a host via the Design Tool and then define entities for terminal screens, which may include patterns for identification, attributes to specify the location to input data, and one or more operations to allow programmed traversal of the host application, and variables which can be mapped to various attributes or various entities.

In most cases, you will use tables and procedures to create an abstraction of the host data so that it can be queried through a subset of the industry-standard Structure Query Language (SQL). See "Abstracting a Host Application" below.

This model, an object in the form of a .model file, is saved in the Design Tool and then copied to a Host Integrator Server. For more information, see The Modeling process.

Abstracting a Host Application

You can create procedures (and underlying tables) to add a database abstraction layer on top of your host application model. Client application programmers can then access this database abstraction layer, either by a direct call to a procedure or through a subset of the industry-standard Structured Query Language (SQL). For an SQL query, the client application specifies a table, a set of input parameters, and a set of desired output parameters. Host Integrator then returns the desired data to the client application.

Providing Core Runtime Services

In addition to the definition process, the Design Tool provides server-like services for the modeling and procedure definitions. This permits the user to test and debug models and database procedures prior to deployment. The model layer requires entity recognition, operation execution, and variable reads and writes. The debug layer takes arbitrary input and resolves a query (or returns an error) or executes a specified query.

Recording Command Lists

The command list recorder records host commands for operations required by the debug layer. On the Model menu, point to Record and then click Start Recording to begin. For information about creating login, logout, and move cursor command lists see Command List Edit.

Implementing Preferences

There are several functional user preferences that can be implemented, including creating default names for attributes, automatic pattern generation, and proposing new operations when appropriate. On the Settings menu, click Preferences for more information.

Providing Online and Offline Design Modes

The Design Tool has the ability to display in online and offline design modes. As each entity is defined, two files are created to enable the design mode process.

Offline mode is available for all emulation options, while Host Emulator is available for IBM 3270 and 5250 emulations only.

Adding Event Handlers

An event handler gives you the ability to customize the behavior of a model.

The Design Tool offers a variety of features that assist you in creating event handlers. The result is a Java class that conforms to rules for event handling. This class is then mapped (attached) to specific objects of a model to customize its behavior.

You can attach event handlers to events associated with the entire model, a life cycle event, or to entities, attributes, operations, recordsets and recordset fields, and procedures. You can reuse a handler in multiple models or with multiple objects of the same type within the same model.