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Foglight Evolve 9.0 - Web Component Guide

Introducing the Web Component Framework The Web Component Framework Configuring Views and Context Queries Functions Bindings Additional Components

Views Tab

The Views tab is used in the Iterator (where it is called an Iterator View), PDF Layout, Switch, Tab Container, Topology, and Type containers. The tab incorporates an editor for setting views for the container.

Context Tab

Context is the term used for the information available at a given point in time to the various components used by the Web Component Framework. Context in the Web Component Framework is similar to a collection of variables that are used in programming languages or an operating system’s environment variables.

Context Inputs are defined in the Context tab when editing the definition of a component.

Figure 27. Context Inputs

Every element of the context has a key (name), a corresponding type, and a run time value in an active Foglight instance.

The key used to reference the object in other dialog boxes or scripts.

Note that the timeRange key should be kept in the list of defined keys even if the page is not dependent on the time range.

A more descriptive name for the key.

Choices are Required, Optional, or Internal.

True if the key is associated with a list, False if it is associated with a single item, and Unknown if it might be either.

The data type of the object and the source of the data object referenced by the key. The choices are in the Select Type dialog box.

A fallback value must be set if the Usage is Optional or Internal. The value is set using the binding editor.

For example, a view that is configured to display alarm data for any one host must be provided with a specific host to give it context. Similarly, a Memory Usage page, which displays memory data for a specific host given a time range, must be provided with two context inputs. In the first example, the host is the context. In the second example the host and the time range together comprise the context.

Pages and views can be compared to forms whose fields are filled in at run time. The context definitions determine the actual data that is specified by the Context, which is set in the following ways:

For example, a page is designed to display information for a selected host. When you click a link, the host object is passed to a detail page. The detail page uses that information as its initial context settings. The Context tab is where you set up the list of required context data. Using a required Context setting means that the page or view is dependent for its data on that context value being available.

Context Tab

Context allows you to define the list of information that is required for a particular view to display the data that the page is designed to show. When a context element is defined it is given a name key and it is assigned a data type.

In any application there is global or application level context, which is the information that is available throughout the application. An example of this type of context is timeRange. Each application can decide to make arbitrary information available to all views.

Context is implemented so that changes to one context element affect other elements in a hierarchy. If a context element changes in a nested level, the change traverses up the hierarchy to the parent level, assuming that an uninterrupted chain of key definitions exists.

When a user interacts with views the interaction can cause changes to the context. For example, when selecting a particular item in a drop down list, by default the Web Component Framework saves the last known values so that when you return to the page, it displays with that same item selected.

Context Types

See also Context tab .

There are three types of context entries:

If a view has only one context input other than timeRange or only one required context input (and zero or more optional inputs), it becomes its primary context input. The primary context input and its priority controls whether it appears in data browsers when a node of that type is selected.

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