In addition the web application displays certain information

In addition, the web application displays certain information about the layers being viewed on the map at any given moment. This is done by the Legend component (left center), and as with the Map component, it acquires the necessary information from the LayerInfo component. Continuing examination of the figure, at the bottom there is a report (in table format) in the middle and two graphs (a pie chart and a bar chart) on the left. Both the report (ReportResults component) and the graphs (Piechart and Barchart components) only display information. Another component (TableParser) is responsible for generating the information and providing it where it is needed. Finally, on the right, there is an external RSS service for REDIAM notices. This service, which has been encapsulated in a component (called RSS), is an example of how services or external components can be seamlessly integrated in our architecture, although with some limitations. As seen in the example, it is possible to build web applications where the components can be used for several purposes, e.g., to interact with the user, display information, for background activities (with no user interaction), to group others and form more complex components, or to integrate third-party resources. This FRAX486 sale is analyzed in detail in Subsection 3.1. All the components that can be used in an application can be described by a set of abstract components [41]. The right-hand side of Fig. 2 shows an abstract representation of the sample web application scenario. This figure shows only the components which include a user interface. Therefore, the TableParser component does not appear in it. The proposed component-based architecture model with which the visual component mode can be disabled so only their features can be worked with, is more easily understood in Chromosome walking figure. Having described the example scenario, the structure of our component architecture and the relationships that exist between the various elements involved in this architecture are examined below.
COTSget-based Architectures This section describes how our COTSget-based architectures are defined. We use a design inspired by MDE to build a Domain-Specific Language (DSL) of the architecture, as can be seen in the metamodel of Fig. 3. This metamodel defines the abstract syntax of our DSL and is described using object-oriented constructs [13] because we use MOF [29] as our metamodeling language. This representation helps us to understand the different parts that make up the architectures. Looking at the figure, our architectures are composed of two types of models, the Abstract Architectural Model and the Concrete Architectural Model. As described in the Introduction, the former identify abstract components, that is, the types of components an architecture must include to be considered correct. On the other hand, the concrete architectural models identify the concrete components that have been selected as a solution for the types defined in the abstract architectural models. Furthermore, both types of architectural models identify the relationships and links which can be established among components, as described below. This article focuses on the concrete architecture models as discussed in the introduction. Therefore, hereafter, our discussion about component architectures refers to architectures of concrete components.