This paper presents a web portal created for Preschool institution in Zrenjanin, Serbia. This portal is created to present most relevant information and it is based on underlying CMS (Content Management System). The web portal was created in 2014 and refactored in 2020, in aim to adjust to new PHP hosting platform. In solving problem of uncertain exact time of hosting upgrade (shift from PHP 5 to PHP 7 support), it was necessary to include automation in detecting and adjustments to hosting platform change. Therefore, self-adaptation mechanism was developed and included in the solution, to provide constant availability of web portal, regardless the hosting platform change. Self-adaptation mechanism is based on sensor-effector approach.
Software changes are inevitable, since their application is closely related to constant advancements
in hardware and software technology, as well as organizational transformations. Therefore, software
maintenance becomes one of the most relevant areas in software lifecycle, which implies the need for
systematic approach and standardization [
With introducing agile approach to software development [
This paper presents an approach to solve the problem of web applications adjustments to hosting platform change, i.e. upgrade. It presents the concept and implementation of the self-adaptive software solution that is able to adjust to the change of hosting platform technology. The approach is illustrated with a case study of maintenance of the official web portal for Preschool Institution in Zrenjanin, Serbia http://www.predskolskazr.edu.rs/. Particularly, it describes refactoring and selfadaptive mechanism implementation in web application to support change of hosting platform from PHP5 to PHP7 without any web portal functionality impact.
The rest of the paper is organized as follows: second section presents background with theoretical concepts, section three related work, section four functional and structural design of developed web portal, section five the proposed approach to hosting platform related self-adaptation mechanism; section six conclusions and future work, followed by acknowledgements and references list.
The concept of adaptive software is defined as a software that dynamically adjusts behavior during
execution, as a response to changes in working environment [
It is relevant to make distinction in terminology [
Software adaptability and adaptivity has been developed by introducing appropriate concepts and
practical implementations. Some of relevant terms that were introduced in related work include: basic
adaptivity vs. intelligent adaptation [
Implementation-related research of software adaptivity has addressed human perspective of
software adaptivity (i.e. adaptive user interface), operative environment and working context, as well
as software architecture [
Concept of adaptivity and self-adaptivity has been analyzed and implemented within variety of software architectures and platforms: multimedia web-based systems [17], distributed software systems [18] , Embedded Systems [19], software based on service-oriented architecture [20], mobile applications [21].
Self-adaptivity of web applications are mostly related to automated adaptation in relation to users and their behavior [22, 23, 24, 25]. Structure aspect of self-adaptive software, particularly web applications has been explored in [26, 27]. Diversity of techniques have been proposed and implemented, particularly for web applications adaptivity: • Model-based adaptive web applications [25, 28] • • • •
Component-based adaptive web applications [26] Active rules application in runtime adaptivity[29] Service-oriented adaptive web applications[30]
Adaptivity for interoperability with devices and services [20].
Platform-related self-adaptivity has been addressed in PhD Thesis [31] that addresses context management and situation-aware smart software systems.
First version of web portal of Preschool Institution Zrenjanin has been designed and implemented in 2014 as a PHP5/MySQL web application, in aim to present contents that were previously supported by WordPress solution. This solution has been presented in [31].
Refactoring of this solution from 2014 has been conducted in 2020, in aim to transform existing solution to be active at new hosting platform – PHP 7. Graphical design and functionality remained the same in 2020 version, but the underlying implementation was changed by refactoring to objectoriented solution and it now included hosting platform-related self-adaptive mechanism.
The similar idea of hosting platform-related self-adaptive mechanism was implemented in 2018, within the same institution web portal subsection, related to a particular project of supporting interinstitutional data integration and decision support (published in [32]), but it was not implemented for the primary web portal of Preschool Institution, until 2020. Therefore, the solution of implementing hosting platform-related self-adaptive mechanism for the primary web portal of Preschool institution Zrenjanin, Serbia (www.predskolskazr.edu.rs) [33] is presented in this paper. 4.2.
Preschool web portal [33] was designed as a multi-page PHP-based web application, which has two mayor parts:
Electronic admissions
About – history and organization
Kindergardens Advices Gallery Contact institution work
Events
Public procurements • •
Administrative module (personalized for web portal administrator) – Content management system, that is used to enable administrator to enter texts and upload documents and images, as additional material with texts.
Presentation module (non-personalized, any web portal visitor) – with static pages (pure HTML) and dynamic pages (reading content recorded within the administrative module. Following table presents list of web pages and their use:
Adding news (data are categorized and presented in news, events and procurements pages)
Tabular presentation of news
News deletion Upload of files (attachments to news)
Attachments description data entry
Tabular presentation of attachments
Deleting attachments records all
Next figure presents UML USE CASE diagram with presentation of software functions supported in both segments – presentational and CMS. Presentational part of web portal is presented at Figure 3, including news with images or documents as attachment to the main text of the news.
Administrative part of web portal is presented at Figure 4, with an example of web form for news data entry and recording, as well as attachment upload and web form for data entry about additional data about the attachment.
Figure 4. Essential pages of CMS part of Zrenjanin Preschool Institution web portal [33]
platform-related
The structure of web portal [33] is presented also with UML component diagram at Figure 5. The problem that this solution addressed was uncertainty of the exact time of shifting the hosting platform of the portal [33] from PHP5 to PHP7 support. Therefore, there should be a self-adaptation mechanism based on “sensors-effectors” approach, that could provide smooth transition from previous to upgraded hosting platform, without affecting the availability and functionality of the portal. The portal should have 24/7 availability.
At the lowest place in hierarchy there are semantically-rich classes that inherit class “Tabela”. By inheritance, they receive technology part, but they use methods from Tabela by inserting semantics, i.e. SQL queries according to appropriate database table they refer to. The hierarchy of classes at Figure 6 enables application of “sensor-effector approach” at self-adaptive mechanism, but also the distinction of technology and semantics enables better support to any future maintenance needs.
The proposed solution of the self-adaptation mechanism within web portal [33] is presented with parts and appropriate PHP code listings, to elaborate the approach: •
Sensor part – detecting PHP version (within the Connection class)
• •
Decision part – deciding which type of commands to use (PHP5 or PHP7) Effector part – apply the selected type of commands to regular work of data entry and data presentation Listing 2. The decision and effector part of self-adaptation mechanism for connecting to a database Listing 3. The decision and effector part of self-adaptation mechanism for running queries upon database
The research problem of this paper is related to self-adaptivity of web applications, regarding hosting platform technology change. This problem is particularly important during software maintenance, when shifting from one to another technology support, i.e. upgrading the hosting technology.
This paper presented the theoretical background related to the concepts of self-adaptive software, as well as related work with similar research results. It could be concluded that there are many research results related to adaptation of software to a user, as well as results in diversity of software adaptation techniques, methods and approaches. It is presented that there are also significant research results in the area of adaptive web application. However, there are not many previous research results related to changes of technology at web application hosting and approaches how to solve the problem of smooth transition between previous and upgraded hosting platform. In this context, this paper contributes with addressing these issues and proposes a simple solution based on “sensor-effector” approach.
Future research could be conducted to explore the impact of technology change frequency to software change requirements by classification and measurements of change requests according to the roots (technology, business needs, user requirements and needs). Other research could be related to approaches and techniques of automating software reengineering and creating self-adaptive mechanism, based on introducing new programming languages or their upgraded versions.
1) “Platform adaptation of existing PHP web application as a administration system of official web site of Preschool institution, Zrenjanin (www.predskolskazr.edu.rs) and migration to new hosting platform“, financed by Preschool Institution Zrenjanin, 2) “Development of software tools for analysis and improvements of business processes”, project No: TR32044, financed by Ministry of science, education and technology development of Republic of Serbia.
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