Common JET Tags

JET includes four tag libraries, which are collections of related tags. These are:

Although there are many tags available, only a few are needed to get started. These tags are either control or workspace tags

Most common control tags

Control tags usually access the input model, and either produce a value, or cause an action based on the information extracted from the input model. The control tags access the input model via XPath expressions. (See Essential XPath). Three control tags are used frequently:

Most common workspace tags

Three workspace tags are used frequently:

Accessing model elements within tag attributes

Frequently, templates must use a model value in a tag's attribute. For example, the name of a generated file might depend on a value from the input model. To do this, the main.jet template would require a ws:file that looks like:

    <ws:file template="..." path="... value from the model..."/>

Because JET does not permit one XML tag to be embedded in an attribute value of another, JET provides Dynamic XPath Expressions, which can be used only in tag attribute values. The format of a dynamic XPath expression is:

    {XPath expression}

So, the ws:file tag above would be written as:

    <ws:file template="..." path="{XPath expression}"/>