Data Binding

In the following sections, we'll cover ZK Bind's annotations used on a ZUL. They are all used in component's attribute and have general format described in Annotate in ZUML:

@AnnotationName(attr-name1=attr-value1, attr-name2=attr-value2)

@AnnotationName(attr-name1={attr-value1-1, attr-value1-2}, attr-name2=attr-value2)

Basically, the syntax consists of an annotation name with comma-separated key-value pairs. The binder treats an annotation's attribute value as an EL expression, and sets an EL expression without a attribute name to default attribute name "value". All annotations must define default attribute's value.

• @[AnnotationName]( [EvaluateOnce EL-expression] )

[AnnotationName]

It could be one of [ id | init ]

[EvaluateOnce EL-expression]

The EL expression will only be evaluated once when parsing.

When using with @id, we strongly suggest you to use string literal to give ViewModel's id.

• @[AnnotationName]( [EL-expression] )

[AnnotationName]

It could be one of [ bind | template | ref ]

[EL-expression]

It could be any ZK allowed EL expression (an internal link to EL) without ${ } enclosed.

• @[AnnotationName]( [EL-expression], [conditionKeyword]=[EvaluateOnce EL-expression] )

[AnnotationName]

It could be one of [ load | save ]

[conditionKeyword]=[EvaluateOnce EL-expression]

This expression is optional unless you want to save or load upon a command.

[conditionKeyword]

It could be one of [ before | after ]

[EvaluateOnce EL-expression]

The evaluation result must be one or more command name.

Command name must correspond to the name specified in Java annotation @Command in a ViewModel.

• @[AnnotationName]( [EL-expression], [arbitraryKey]=[EL-expression] )

[AnnotationName]

It could be one of [ command | global-command | validator | converter ]

[arbitraryKey]=[EL-expression]

It's key-value pairs basically. You can write multiple key-value pairs with different key names.

An EL expression without key is set to a default key named "value" implicitly.

Due to each annotation has different functions, some annotations may ignore key-value pair expression other than default key, e.g.@id.

[arbitraryKey]

It could be any name, it's used as a key for parameter related Java annotation in a ViewModel.