Package org.apache.tapestry5.annotations
Annotation Type Parameter
@Target(FIELD)
@Documented
@Retention(RUNTIME)
@UseWith({COMPONENT,MIXIN})
public @interface Parameter
Annotation placed on a field to indicate that it is, in fact, a component parameter. Parameters may be optional or
required. Required parameters must be bound.
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Optional Element Summary
Optional ElementsModifier and TypeOptional ElementDescriptionboolean
If false, and the parameter is bound, then the value for the parameter must not be null.boolean
Used to create a default binding, connecting the parameter to a property of the container whose property name matches the id of the component.boolean
If true (the default), then the value for the parameter is cached while the component is, itself, rendering.The default binding prefix for the parameter, if no specific binding prefix is provided with the binding.The name of the parameter.boolean
Used to mark a parameter as requiring earlier initialization than other parameters.boolean
If true, the parameter is required and and must be bound.The default value for the parameter if not bound.
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Element Details
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name
The name of the parameter. If not specified, the name of the parameter is derived from the name of the field (after stripping off leading and trailing punctuation).- Default:
- ""
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required
boolean requiredIf true, the parameter is required and and must be bound. If false (the default), then the parameter is optional.- Default:
- false
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allowNull
boolean allowNullIf false, and the parameter is bound, then the value for the parameter must not be null. The default is true, to allow nulls. This is different than required, in that the parameter may be bound, but bound to a null value.- Default:
- true
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cache
boolean cacheIf true (the default), then the value for the parameter is cached while the component is, itself, rendering. Values from invariant bindings (such as literal strings) are always cached, regardless of this setting. Set this attribute to false to force the parameter to be re-read every time the field is accessed, even while the component is rendering.- Default:
- true
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value
The default value for the parameter if not bound. This is a binding expression, typically the name of a property of the component to bind. The default value for this attribute is the empty string, indicating that there is no default default binding.- Default:
- ""
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defaultPrefix
The default binding prefix for the parameter, if no specific binding prefix is provided with the binding. There is rarely a reason to override this. Typically, non-standard default binding prefixes are paired with specificBindingFactory
implementations, and used with parameters whose name reflects the binding prefix.- See Also:
- Default:
- "prop"
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principal
boolean principalUsed to mark a parameter as requiring earlier initialization than other parameters. This is used when default bindings for secondary parameters rely on a principal parameter, which itself may have a default value. This ensures that the binding for the principal parameter(s) are initialized, possibly involving a defaulter method, before the secondary parameters are initialized (as they may need to know if the principal parameter is bound, and what type of value it is bound to). This is rarely used, and it is highly unlikely a single component would have more than a single principal parameter.- Default:
- false
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autoconnect
boolean autoconnectUsed to create a default binding, connecting the parameter to a property of the container whose property name matches the id of the component. This is frequently used for form element components. This default binding is only used if there is no matching container property.- Default:
- false
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