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org.apache.tapestry5.annotations
public class: Parameter [javadoc | source]
org.apache.tapestry5.annotations.Parameter
Annotation placed on a field to indicate that it is, in fact, an parameter. Parameters may be optional or required. Required parameters must be bound.
Method from org.apache.tapestry5.annotations.Parameter Summary:
allowNull,   autoconnect,   cache,   defaultPrefix,   name,   principal,   required,   value
Method from org.apache.tapestry5.annotations.Parameter Detail:
 boolean allowNull() 
    If true, and the parameter is bound, then the value for the parameter must not be null. The default is to allow nulls. This is different than required, in that the parameter may be bound, but bound to a null value.
 boolean autoconnect() 
    Used 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 parameter is not bound.
 boolean cache() 
    If 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.
 String 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 specific org.apache.tapestry5.services.BindingFactory implementations, and used with parameters whose name reflects the binding prefix.
 String 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 punctuation) from the field name.
 boolean principal() 
    Used 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.
 boolean required() 
    If true, the parameter is required and and must be bound. If false (the default), then the parameter is optional.
 String value() 
    The default value for the parameter if not bound (at not the empty string). This is a binding expression, typically the name of a property of the component to bind.