In addition to the individual editors in AltoStudio for objects such as JSP pages, XML pages, and Java classes, external editors may be registered for each object to give the developer access to the full range of capabilities provided by those specific tools.

Development in AltoStudio
For this review, I'll create a simple application that accesses user information in an Oracle database. The initial setup will involve establishing a SQL Data Source object that will use a connection from an existing pool in WebLogic. AltoStudio provides the ability to access a connection object through a JNDI lookup by simply specifying the name of the connection object. Alternatively, AltoStudio can access a database through a JDBC driver.

The first step to representing the User as an object available to other components is to create a MetaObject. The MetaObject, linked to a specific data store, provides a layer of abstraction isolating the details of the data storage mechanism from the components that will access it. The definition of a MetaObject consists of fields and operations. The fields may be created from a custom SQL statement or selected directly from a list of available tables and columns. Operations are defined to manipulate the item represented by a MetaObject. For example, several Select operations may be defined to handle lookups or searches by various fields. These operations may be created from SQL statements or by applying one of the available filter types.

Once the data sources and the MetaObjects have been created, process logic may be created to perform the business operations on the data. Process objects are created by diagramming the operations in a process view. The process view contains individual component operations, each with their own inputs and outputs.

In the example in Figure 2, the process executes the function GetUserById. The function maps the input parameter to a defined select operation on the User MetaObject and produces three outputs. The function outputs are then mapped to the process outputs.

Information is transported within and among processes by DataModel objects. These containers provide temporary storage for runtime data and may be shared across components.

Along with the provided modules that may be inserted into processes, AltoStudio also provides the ability to create custom components by coding Java classes. When creating a Java class, the developer defines the input, output, and any custom runtime parameters used during execution. AltoStudio then generates the skeleton Java code for a subclass of ProcessWorker. The developer then has the option to launch an IDE that has been associated in AltoStudio to complete development on the class. When finished, this class is available in the Process editor as an executable component.

Once the process has been defined and the appropriate DataModels assigned and created, an interface must be created to allow other processes to act upon it. The interfaces are defined by Action components. Three types of Action components exist in AltoStudio: Actions, XML Actions, and Web Service Actions. The standard Action object is used in browser-based applications to call a target process, custom class or pass data to a public Data Model. The end result of an action is a JSP view or a URL. XML Actions allow AltoWeb to manage client requests in XML format. Web Service Actions allow AltoWeb processes to be executed via SOAP calls. Once defined, the Web Service Actions may be published to a UDDI registry from within AltoStudio.

Web Service Actions may be created from scratch or from an existing WSDL definition. To create the action from an existing definition, an active UDDI registry must be available for AltoStudio to browse. Once available, the developer selects the definition desired and AltoStudio creates a new process with the corresponding data models and structures defined in the WSDL document. When creating a service without an existing WSDL definition, the developer must follow specific naming and data structure conventions outlined in the documentation.

Finishing Up
Throughout the development process, AltoStudio is linked with the host application server to store applications. This gives the developer the flexibility to test the application from an external client throughout the development cycle. With the combination of Web Service Actions, JSP Views, and XML Views, the application is available from very distinct types of clients with minimal development effort. The underlying business process is independent of the access method created for that process. In the case of the User Lookup Web Service Action I've created, AltoStudio generated the necessary SOAP call required to test the service and retrieve the results.

Summary
The AltoWeb Application Platform provides an integrated environment to de-velop, test, deploy, and manage Web-based and services-based applications. The AltoStudio development environment provides developers with the tools to create business-oriented applications without requiring a low-level knowledge of J2EE and Web services technologies. Its flexibility does present a learning curve for new developers, but once acclimated, the tool is effective. Overall, the AltoWeb Application Platform is a solid tool that can improve the development of Web- and services-based applications.

Contact:
Steve Wilkes
Principal Technologist
1731 Embarcadero Road
Palo Alto, CA 94303 i
650 251-1591
swilkes@altoweb.com

Pricing:
Platform starts at $3500 per developer seat

Test Environment:
Pentium III
256 MB RAM
Windows XP Professional
Oracle 8i
BEA WebLogic 6.1
JDK 1.3.1

Author Bio
Brian R. Barbash is a consultant for the Consulting Group of Computer Sciences Corporation. He specializes in application architecture and development, business and technical analysis, and Web design. bbarbash@csc.com