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A Model and A Computer Program Product for Portable Object Query Service with Pluggable Support for External Resources

IP.com Disclosure Number: IPCOM000016592D
Original Publication Date: 2003-Jul-01
Included in the Prior Art Database: 2003-Jul-01
Document File: 4 page(s) / 103K

Publishing Venue

IBM

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  A Model and A Computer Program Product for Portable Object Query Service with Pluggable Support for External Resources

A Portable Object Query Service with Pluggable Support for External Resources

Mei-Mei Fu, mfu@us.ibm.com

Abstract

Disclosed is a model that separates the Object Query Service from the underlying runtime server and makes it a portable, reusable service. Application specific information to be queried against can be easily plugged in without any impact to its underlying system.

Introduction

Today's e-business model has become overwhelmingly prevalent in the world. Most web-based applications are written in Java, an object-oriented programming model. For Java programmers to query an existing database, mostly are via a JDBC package which relies on the use of Structural Query Language (SQL). SQL is a table/record oriented query language. It is an usage discrepancy to OO programmers and users. To bridge this gap, a service that allows queries based on application defined objects and attributes is desired and this concept is well accepted today. However, current approaches to provide such service are via embedded components in the application server or its underlying server framework, such as CosQuery service in Component Broker[1] . The query service is inseparable from the underlying application server runtime. The portability and reuseability of the service is limited .

This work proposes a model that separates the Object Query Service from the underlying runtime server and makes it a portable, reusable service. With the proposed model, any object-oriented application server can easily plug in the Object Query Service without any impact to its underlying system

Design

An effort in this work is to identify the major required information that an Object Query Service has on a running server and model the information into a single pluggable interface. This interface allow the application server to provide its own specific object-table mapping information and processing preference (Figure 1). A service access bean is devised to facilitate the plug-in and validation, and to serve as an service access entry.

access bean

Obj ect

 Quer y Servi ce

c lie n t

clien t

plugin

A pplication

s e r v e r

c lie n t

Figure 1

The configuration interface which faciliate the plug-in is extendible but must consist of three essential public APIs:

An API to the schema metadata allows the application server to plug in the application

specific object-data schema mapping information[3]. The information is in an editable XML format. The information must be validated by a DTD provided by the Service. An API to the object factory allows the application server to plug in the application specific

object building function(s). This function allow the Query Service to construct specific


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object based on the retrieved data tuple. An API to the data source allow the application ser...