Tag Name: <a2:param />

Description

Parametrize other tags

This tag can be used to parameterize other tags.

The parameters can be added with or without a name as key. If the tag provides a name attribute the parameters are added using the {@link Component#addParameter(String, Object) addParamter} method. For unnamed parameters the Tag must implement the {@link UnnamedParametric} interface defined in this class (e.g. The TextTag does this).

This tag has the following two paramters.

• name (String) - the name of the parameter
• value (Object) - the value of the parameter

Note: When you declare the param tag, the value can be defined in either a value attribute or as text between the start and end tag. Struts behaves a bit different according to these two situations. This is best illustrated using an example:
<param name="color">blue</param> <-- (A) -->
<param name="color" value="blue"/> <-- (B) -->
In the first situation (A) the value would be evaluated to the stack as a java.lang.String object. And in situation (B) the value would be evaluated to the stack as a java.lang.Object object.
For more information see WW-808.

Examples

 <ui:component> <ui:param name="key" value="[0]"/> <ui:param name="value" value="[1]"/> <ui:param name="context" value="[2]"/> </ui:component> 

where the key will be the identifier and the value the result of an OGNL expression run against the current OgnlValueStack.

This second example demonstrates how the text tag can use parameters from this param tag.

 <a:text name="cart.total.cost"> <a:param value="#session.cartTotal"/> </a:text> 

Attributes

Name	Required	Default	Type	Description
name	false		String	Name of Parameter to set
value	false	The value of evaluating provided name against stack	Object/String	Value expression for Parameter to set
id	false		Object/String	id for referencing element. For UI and form tags it will be used as HTML id attribute