Creating Custom Adaptive Tags

The Adaptive Tag Framework allows you to create custom tags for use in pagelets and gatewayed pages.

The ATag class is the base class used to write custom tags

To implement a custom tag, follow the steps below.

. To implement a new tag, you must have a tag library. A tag library is simply a .jar or .dll file with exactly one class that implements ITagLibraryMetaData.

Java

public static final TagLibraryMetaData LIBRARY = new TagLibraryMetaData
("Sample Tags", "sample", "This library provides sample tags.", 1.0);

.NET

public static readonly TagLibraryMetaData LIBRARY = new TagLibraryMetaData
("Sample Tags",  "sample", "This library provides sample tags.", 1.0);

Create one public static final ITagMetaData member variable that provides the name and description of the tag. Create a public static final RequiredTagAttribute or OptionalTagAttribute member variable for every attribute that the tag supports. You can also use standard HTML and XML attributes; see Accessing Attributes in Custom Adaptive Tags.

Java

public static final ITagMetaData TAG;
public static final RequiredTagAttribute MESSAGEATTRIBUTE;
public static final OptionalTagAttribute LOCATIONATTRIBUTE;

static
{
TAG = new TagMetaData("hellolocation", "This tag displays a hello message for the given location.");
MESSAGEATTRIBUTE = new RequiredTagAttribute( "message", "The message to display for hellolocation tag", AttributeType.STRING); 
LOCATIONATTRIBUTE = new OptionalTagAttribute("location", "The sample location attribute for hellolocation tag", AttributeType.STRING, "World");
}

.NET

public static readonly ITagMetaData TAG;
public static readonly RequiredTagAttribute MESSAGEATTRIBUTE;
public static readonly OptionalTagAttribute LOCATIONATTRIBUTE;

static HelloLocationTag()
{
TAG = new TagMetaData("hellolocation", "This tag displays a hello message for the given location.");
MESSAGEATTRIBUTE = new RequiredTagAttribute( "message", "The message to display for hellolocation tag", AttributeType.STRING); 
LOCATIONATTRIBUTE = new OptionalTagAttribute("location", "The sample location attribute for hellolocation tag", AttributeType.STRING, "World");
}

Type validation is performed by the tag framework automatically. If an optional attribute is not present in the HTML, the tag framework will use the default value. In the same code below, the optional attribute has a default value of "World.".

Implement the DisplayTag abstract method. Use this method to create and display HTML. To display any HTML and tags defined within the tag, call ProcessTagBody and return the resulting HTML. The sample code below adds the "Hello" string with a user-specified location to an HTMLElement and returns it to be displayed.

Java

public HTMLElement DisplayTag()
{
String strLocation = GetTagAttributeAsString(LOCATIONATTRIBUTE);
String strMessage = GetTagAttributeAsString(MESSAGEATTRIBUTE);
HTMLElementCollection result = new HTMLElementCollection();
result.AddInnerHTMLString(strMessage + strLocation + "!");
return result;
}

.NET

public override HTMLElement DisplayTag()
{
String strLocation = GetTagAttributeAsString(LOCATIONATTRIBUTE);
String strMessage = GetTagAttributeAsString(MESSAGEATTRIBUTE);
HTMLElementCollection result = new HTMLElementCollection();
result.ddInnerHTMLString(strMessage + strLocation + "!");
return result;
}

If the tag should not display any HTML contained within the tag, use the GetTagType method to return TagType.NO_BODY.
Java
```
public TagType GetTagType()
{
return TagType.NO_BODY;
}
```
.NET
```
public override TagType GetTagType()
{
return TagType.NO_BODY;
}
```

Implement the Create abstract method to return a new instance of the tag.

Java

public ATag Create()
{
return new HelloLocationTag();
}

.NET

public override ATag Create()
{
return new HelloLocationTag();
}

The ATag class allows you to include a wide range of functionality in custom tags. For a full list of interfaces and methods, see the tagdocs. For links to all tagdocs, see API Libraries. For details on deploying your custom tag, see Deploying Custom Adaptive Tags.

Accessing Browser Session Information in Custom Adaptive TagsTo access browser session information from a custom adaptive tag, use the IEnvironment class.
Accessing Attributes in Custom Adaptive TagsTo access attributes used in a custom tag, use one of the GetTagAttribute* methods.
Storing and Accessing Custom Data in Custom Adaptive TagsTo store custom data as member variables using a custom tag, use the SetStateVariable or SetStateSharedVariable methods. To retrieve it, use GetStateVariable or GetStateSharedVariable.
Including JavaScript in Custom Adaptive TagsTo include JavaScript in a tag, use the AddJavaScript method inside the DisplayTag method.
Using Nested Tags in Custom Adaptive TagsTags can be used within other tags. To implement nested tags, use the RequiredParentTag, RequiredChildTag and RelatedChildTag member variables.
Implementing Non-Standard Custom Adaptive Tag TypesTo implement non-standard tag types in custom adaptive tags, including 508-accessible, looping or singleton tags, override the associated method.
Deploying Custom Adaptive TagsTo deploy custom adaptive tags, follow these steps.

Parent topic: About Adaptive Tags

AquaLogic User Interaction Development Guide

Creating Custom Adaptive Tags