public class If extends AbstractConditional
Component Parameters | ||||||
---|---|---|---|---|---|---|
Name | Description | Type | Flags | Default | Default Prefix | Since |
else | An alternate org.apache.tapestry5.Block to render if org.apache.tapestry5.corelib.base.AbstractConditional#test() is false. The default, null, means render nothing in that situation. | org. | literal | |||
negate | Optional parameter to invert the test. If true, then the body is rendered when the test parameter is false (not true). | boolean | prop | |||
test | If true, then the body of the If component is rendered. If false, the body is omitted. | boolean | Required | prop |
<html xmlns:t="http://tapestry.apache.org/schema/tapestry_5_1_0.xsd" xmlns:p="tapestry:parameter"> <body> <h1>Welcome!</h1> <t:if test="user"> Welcome back, ${user.firstName} <p:else> <t:pagelink name="login">Login</t:pagelink> / <t:pagelink name="register">Register</t:pagelink> </p:else> </t:if> . . . </html>
Here, the main text is rendered if the user is logged in (the user property will be non-null after the user logs in). Otherwise, links to a login and register page are rendered.
Note the use of the
p:
namespace (new in Tapestry 5.1). In 5.0, this would be
.
Tapestry has many built in coercions to boolean:
public If()
protected boolean test()
AbstractConditional
test
in class AbstractConditional
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