Abstract True-Push-Communication Integrated Style for Rich Web-based Applications

Rich Web-based Applications provide a higher user experience compared to traditional web applications using rich graphical user interfaces and the advanced Delta-Communication model to communicate with the server. Delta-Communication works in both pull and push modes. Pull-communication is based on the request-response model, and Push-Communication can be implemented by either exploiting the request-response model to simulate Push-Communication or implementing True-Push-Communication by using a technology like WebSocket, for the server to push data to the client(s) without receiving a request(s) from the same clients. RiWAArch style is an abstract hybrid architectural style that realises the formalism of pull-communication-based Rich Web-based Applications.

Rich Web-based Applications benefit from Push-Communication-based functionalities like push notifications and real-time updates; however, there are no abstract architectural styles which can realise the integration of True-Push-Communication into Rich Web-based Applications. Software architecture provides an overall picture of a system and assists in realising the system by depicting the configuration of the architectural elements: components, connectors, and data. Architectural styles are used to design software architectures. This research aims to introduce an abstract hybrid architectural style, which can realise the integration of True-Push-Communication into Rich Web-based Applications and then demonstrate the adoption of the introduced style via a comprehensive use case. The approach utilised is to extend the RiWAArch style – introduced by the author's early research to fulfil an MPhil study – to realise True-Push-Communication. The resulting style is called the Extended-RiWAArch style (Ex-RiWAArch style in short).

This research has identified the common characteristics and essential features for Push-Communication-enabled Rich Web-based Applications as follows. Common characteristics: push-simulation and True-Push-Communication, push-events triggered in the server, and real-time vs non-real-time Push-Communication. Common essential features: support for push-modes, True-Push-Delta-Communication connectors, and decision-making component for True-Push-Communication. The features to be expected from an architectural style to support these common characteristics and essential features are identified as follows: realise True-Push-Communication and push-modes, include elements for True-Push-Delta-Communication handling in server and client, ability to make True-Push-Communication-related decision making, and support for the standard general functionalities of Rich Web-based Applications. It has been decided that a style should satisfy the following requirements to deliver the features mentioned above: FR1 – realise True-Push-Communication and push-modes, FR2 – centralized True-Push-Delta-Communication handling in server and client, FR3 – True-Push-Communication-related decision-making, FR4 – support the standard general functionalities of Rich Web-based Applications, NFRs – simplicity, visibility, reusability, modifiability (evolvability, extensibility, customizability, and configurability), scalability, performance, portability/adoptability, reliability, TR1 – platform independency, TR2 – development technology/technique independency, and TR3 – low learning curve and easy adoptability.

The functional requirements are exploited as constraints to derive the proposed Ex-RiWAArch style. The non-functional requirements are induced while deriving the style. The technical requirements ensure the abstraction of the resulting style. First, by applying constraint 1 to the client-server style, the True-Push-Communication style is derived and proved that it could realise the push-modes. Then, constraint 2 introduces Delta-Communication connectors to the server and client. After that, constraint 3 introduces a model to support Push-Communication-related decision-making while deriving the Smart True-Push-Communication style. Then, constraint 4 integrates the Smart True-Push-Communication style into the RiWAArch style, extending it to realise True-Push-Communication. Finally, some improvements are applied to complete the proposed Ex-RiWAArch style. Also, using some augmentations, an enhanced version is introduced. Further, based on the enhancements applied to the Ex-RiWAArch style, the RiWAArch style is also improved, and an enhanced version is introduced. The adoption of the introduced Ex-RiWAArch style is demonstrated using a comprehensive use case, which implements all the features of the Ex-RiWAArch style.

The self-evaluation verifies that the Ex-RiWAArch style strongly satisfies all the requirements within the study context. The contextualised comparison shows that the Ex-RiWAArch style highly satisfies the requirements compared to the available solutions. The expert evaluation confirms that the Ex-RiWAArch style satisfies the requirements, and it is a valuable style for True-Push-Communication enabled Rich Web-based Applications.

The satisfaction of the requirements confirms that the introduced Ex-RiWAArch style delivers the expected features. These features assist in implementing the common characteristics and essential features of the Push-Communication-enabled Rich Web-based Applications. The introduction of the Ex-RiWAArch style, which can strongly satisfy the requirements, proves the research hypotheses and confirms the fulfilment of the research aim. This thesis contributes the following to the domain of True-Push-Communication-integrated Rich Web-based Applications: terms and definitions (push-simulation, True-Push-Communication, push-events), features of Push-Communication, common characteristics and essential features of Push-Communication-enabled Rich Web-based Applications, the concept of True-Push-Communication as a style and Smart True-Push-Communication style, the Ex-RiWAArch style, revised and enhanced versions of the RiWAArch style, and a use case to demonstrate adoption of the Ex-RiWAArch style.

This research’s scope is limited to browser-based 3-tier Rich Web-based Applications and keeps non-functional requirements like availability, security, integrity, and usability out of scope. The adoption of different technologies/techniques into Ex-RiWAArch style-based development should be experimented with and discussed. Also, this thesis refrained from addressing Rich Web-based Application engineering activities like designing and testing.