The Java implementation of the toolkit is based on an abstract main class called DSETagSupport. This class extends TagSupport in the standard JSP libraries to work correctly with typed data and their element states in runtime. For example, if an input field must be read only, the browser renders it as read only even though it is not declare read only in the JSP. DSETagSupport uses JSPContextServices to get the information about the model required to set up the JSP PageContext.
Extending DSETagSupport are the following four groups of classes:
▪ Link classes that are used to create a hyperlink. This group consists of the following classes that extend the DSELinkTagSupport abstract class:
▪ FormTag
▪ URITag
▪ AnchorTag (extends URITag)
▪ List classes that are used to create a list. This group consists of the following classes that extend the DSEListTagSupport abstract class:
▪ ButtonGroupTag
▪ ComboBoxTag
▪ LabelListTag
▪ ListTag
▪ Table classes used to create any kind of table. This group consists of the following classes that extend the DSETableTagSupport abstract class:
▪ TableTag
▪ SelectTableTag
▪ EditTableTag
▪ The following classes that directly extend DSETagSupport:
▪ CheckBoxTag
▪ FieldDescriptionTag
▪ FieldErrorTag
▪ InputButtonTag
▪ LabelTag
▪ PageControlTag
▪ RadioButtonTag
▪ TextAreaTag
▪ TextFieldTag
▪ ValidationErrorsTag
The four abstract classes (DSETagSupport and the link, list, and table subgroups) have the set methods needed to initialize the JSP objects from the attributes of each tag declared in the JSP. All of the custom JSP tags have a doStartTag() method to implement the corresponding HTML tag, and the tag classes that need to close the HTML tag have a doEndTag() method. The classes that need to implement an action have do methods.