SmartObjects used in the Order Tracking System
In Chapter 2 "Working with the Sample Application" and Chapter 3, "Assembling the Order Tracking System," you examined the design of the SportsPro sample application and learned to use the AppBuilder to create an application from prebuilt SmartObjects. Figure 4–1 shows the main window of the SportsPro Order Tracking System as it appears when you run it.
Figure 4–1 shows the main window of the sample application and identifies some of the SmartObjects in this window.
Some SmartObjects used in the Order Tracking System above include:
- SmartDataObjects (SDOs) — Sources for Data SmartLinks that target SmartDataViewers and other SDOs.
- SmartFolder — Source for a Page SmartLink that is targeted to a SmartWindow to control paging in that window.
- SmartDataLinks — Establish a communication link from SDOs to SDOs and SDVs.
- SmartDataViewer (SDV) — Displays data from SDOs.
- SmartDataBrowser (SDB) — Displays data from SDOs and allows a user to scroll through the data.
- SmartPanel — Contains buttons that control navigation as a source of a Navigation SmartLink through a SDO’s query.
- Navigation SmartLink — Establishes a navigation SmartLink from a SmartPanel to a SDO.
In addition to the objects listed above, the main window uses a SmartContainer. A SmartContainer is a special kind of SmartObject designed to contain other SmartObjects (including possibly other SmartContainers). OpenEdge supplies three types of SmartContainers:
Each SmartContainer type keeps track of all of the information required to create running instances of the SmartObjects it contains. This information includes the positions of the SmartObjects and how they are linked.
The main window contains different classes of SmartObjects. How a SmartObject functions in an application depends on its class and the SmartLinks defined for the class. SmartLinks are pathways used to send messages among SmartObjects. The set of SmartLinks defined for each class of SmartObject predetermines how that class can interact with other SmartObject classes.
The Progress Advisor that you saw in Chapter 3, "Assembling the Order Tracking System," uses these sets of possible interactions to make suggestions on how to link the SmartObjects in your application. This eases the task of creating complex applications. However, you get the most benefit from it when you know exactly what pathways you want between the SmartObjects before you begin building your application.
Figure 4–2 shows the SmartObjects and the pathways between them in the main window of the Order Tracking System.
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A SmartObject does not know how it relates to other SmartObjects until you create the links. You determine the relationship by using a particular SmartLink type and by specifying which end of the link each object is on (Source or Target). For all SmartLink types, a Source initiates some action or passes some data to one or more Targets. In general, a Source can have numerous Targets simultaneously, but a Target has only one Source at a time. For more information about SmartLinks, see the OpenEdge Development: AppBuilder .
SmartLinks provide direct communication pathways between pairs of SmartObjects. A single SmartObject can relate to other SmartObjects in a variety of ways. For example, a SDO relates to a SDV differently than it relates to a Navigation SmartPanel. Most SmartObjects support a variety of SmartLink types. Some, like the Navigation SmartPanel, supportonly one SmartLink type (Navigation).
SmartLinks are directional in nature. Each SmartLink is directed from a source SmartObject to a target SmartObject. There are several types of SmartLinks. For example, a Data SmartLink sends the contents of a database record, while a Navigation SmartLink sends navigation instructions.
The following figures group the SmartObjects shown in Figure 4–2 based on their SmartLinks. The figures describe the types of SmartLinks and the different types of SmartObjects.
Figure 4–3 shows that the SmartFolder, folder, is the source for a Page SmartLink targeted to the SmartWindow, worder. The Page SmartLink tells the main window which logical page to display.
Figure 4–4 shows that the SDO, dcust, is the source for two Data SmartLinks targeted to the SDV, vcust, and the SDO, dorder.
Figure 4–5 shows that the SDO, dorder, is the source for two Data SmartLinks targeted to the SDV, vorder, and the SDO, dordlne.
Figure 4–6 shows that the SDO, dordlne, is the source for two Data SmartLinks targeted to the SDB, bordlne2, and the SDV, vordlne. The SmartPanel, pnavico, is the source for a Navigation SmartLink to the SDO, dordlne.
