<bean> element

`<bean>` element
	Appendix C. Tapestry Specification DTDs

`<bean>` element

Appears in: <component-specification> and <page-specification>

A <bean> is used to add behaviors to a page or component via aggregation. Each <bean> defines a named JavaBean that is instantiated on demand. Beans are accessed through the OGNL expression beans.name.

Once a bean is instantiated and initialized, it will be retained by the page or component for some period of time, specified by the bean's lifecycle.

bean lifecycle

none: The bean is not retained, a new bean will be created on each access.
page: The bean is retained for the lifecycle of the page itself.
render: The bean is retained until the current render operation completes. This will discard the bean when a page or form finishes rewinding.
request: The bean is retained until the end of the current request.

Caution should be taken when using lifeycle page. A bean is associated with a particular instance of a page within a particular JVM. Consecutive requests may be processed using different instances of the page, possibly in different JVMs (if the application is operating in a clustered environment). No state particular to a single client session should be stored in a page.

Beans must be public classes with a default (no arguments) constructor. Properties of the bean may be configured using the <set-property> and <set-message-property> elements.

Figure C.3. <bean> Attributes

Name	Type	Required ?	Default Value	Description
name	string	yes		The name of the bean, which must be a valid Java identifier.
class	string	yes		The name of the class to instantiate.
lifecycle	`none\|page\|render\|request`	no	`request`	As described above; duration that bean is retained.

Figure C.4. <bean> Elements

<description> ?, <property> *,
(<set-property> | <set-message-property>) *


`<application>` element		`<binding>` element