Examples of org.zkoss.zkplus.databind.AnnotateDataBinder

koss.org/2005/zk/annotation" first. Then declare <a:bind> before component to make the annotation.

We suggest annotating directly on the component property with intuitive @{...} expression because it is more readable.

For example, the following annotation associates the attribute "value" of the component "textbox" to the bean's value "person.address.city".

@{...} way:

 <textbox value="@{person.address.city}"/>

The @{...} pattern tells the ZUML parser that this is for annotation.

<a:bind> way:

 <a:bind value="person.address.city"/> <textbox/>

You can put more metainfo inside the @{...} or <a:bind> so this DataBinder knows what to do. The complete format is like this:

@{...} way:

 <componentX attrY="@{bean's value,[tag='expression']...}"/>

<a:bind> way:

 <a:bind attrY="bean's value;[tag:expression]..."/> <componentX/>

This associates the componentX's attribute attrY to the bean's value. The bean's value is something in the form of beanid.field1.field2... You can either call {@link DataBinder#bindBean} to bind the beanid to areal bean object or you can neglect it and this DataBinder would try to find it from the variables map via {@link org.zkoss.zk.ui.Page#getZScriptVariable} then {@link org.zkoss.zk.ui.Component#getVariable} method. That is, all those variables defined in zscript are also accessible by this DataBinder. Note that you can choose either two formats of annotations as your will and you can even hybrid them together though it is not generally a good practice.

The tag='expression' or tag:expression is a generic form to bind more metainfo to the attrY of the componentX. The currently supported tags includes "load-when", "save-when", "access", "converter", "load-after"(since 3.6.1), and "save-after"(since 3.6.1).

load-when. You can specify the events concerned when to load the attribute of the component from the bean. Multiple definition is allowed and would be called one by one. Note that binding is executed BEFORE other event listeners you defined. (If you want the loading to be executed AFTER your event listener, use load-after). For example, the following code snip tells DataBinder that the attribute "value" of Label "fullName" will load from "person.fullName" when the Textbox "firstName" or "lastName" fire "onChange" event.
The @{...} way that specify directly on the Component's attribute:
```
 <textbox id="firstname" value="@{person.firstName}"/> <textbox id="lastname" value="@{person.lastName}"/> <label id="fullname" value="@{person.fullName, load-when='firstname.onChange,lastname.onChange'}"/> 
```
Or the <a:bind> way that declare in front of the Component:
```
 <a:bind value="person.firstName"/> <textbox id="firstname"/> <a:bind value="person.lastName"/> <textbox id="lastname"/> <a:bind value="person.fullName; load-when:firstname.onChange; load-when:lastname.onChange"/> <label id="fullname"/> 
```
(Since 3.6.1) load-after. Similar to load-when. You can specify the events concerned when to load the attribute of the component from the bean. The only difference is that the loading is done AFTER other event listeners listening to the same event are processed; while in load-when the loading is done BEFORE other event listeners listening to the same event are processed.
save-when. You can specify the events concerned when to save the attribute of the component into the bean. Since ZK version 3.0.0, you can specify multiple events in save-when tag (i.e. before ZK 3.0.0, you can specify only one event). The events specified, if fired, will trigger this DataBinder to save the attribute of the component into the specified bean. Note that binding is executed BEFORE other event listeners you defined. (If you want the saving to be executed AFTER your event listener, use save-after). For example, the following code snip tells DataBinder that the property "value" of Textbox "firstName" will save into "person.firstName" when the Textbox itself fire "onChange" event.
The @{...} way that specify directly on the Component's attribute:
```
 <textbox id="firstName" value="@{person.firstName, save-when='self.onChange'}"/> 
```
Or the <a:bind> way that declare in front of the Component:
```
 <a:bind value="person.firstName; save-when:self.onChange"/> <textbox id="firstName"/> 
```
However, you don't generally specify the save-when tag. If you don't specify it, the default events are used depends on the natural characteristic of the component's property as defined in lang-addon.xml. For example, the save-when of Label.value is default to "none" while that of Textbox.value is default to "self.onChange". That is, the following example is the same as the above one.

The @{...} way that specify directly on the Component's attribute:
```
 <textbox id="firstName" value="@{person.firstName}"/> 
```
Or the <a:bind> way that declare in front of the Component:
```
 <a:bind value="person.firstName"/> <textbox id="firstName"/> 
```
On the other hand, you might not specify the save-when tag nor you want the default events to be used. Then you can specify a "none" keyword or simply leave empty to indicate such cases.
```
 <textbox id="firstName" value="@{person.firstName, save-when='none'}"/> 
```
or
```
 <textbox id="firstName" value="@{person.firstName, save-when=''}"/> 
```
or
```
 <a:bind value="person.firstName; save-when:none;"/> <textbox id="firstName"/> 
```
or
```
 <a:bind value="person.firstName; save-when: ;"/> <textbox id="firstName"/> 
```
(Since 3.6.1) save-after. Similar to save-when. You can specify the events concerned when to save the attribute of the component to the bean. The only difference is that the saving is done AFTER other event listeners listening to the same event are processed; while in save-when the saving is done BEFORE other event listeners listening to the same event are processed.
access. You can set the access mode of the attrY of the componentX to be "both"(load/save), "load"(load Only), "save"(save Only), or "none"(neither). Multiple definition is NOT allowed and the later defined would override the previous defined one. The access mode would affects the behavior of the DataBinder's loadXxx and saveXxx methods. The {@link DataBinder#loadAll} and {@link DataBinder#loadComponent} would load only those attributeswith "both" or "load" access mode. The {@link DataBinder#saveAll} and {@link DataBinder#saveComponent} would save only those attributes with "both" or "save" access mode. If youdon't specify it, the default access mode depends on the natural characteristic of the component's attribute as defined in lang-addon.xml. For example, Label.value is default to "load" access mode while Textbox.value is default to "both" access mode. For example, the following code snips tells DataBinder that Textbox "firstName" would allowing doing save into bean only not the other way.
The @{...} way that specify directly on the Component's attribute:
```
 <textbox id="firstName" value="@{person.firstName, access='save'}"/> 
```
Or the <a:bind> way that declare in front of the Component:
```
 <a:bind value="person.firstName;access:save;"/> <textbox id="firstName"/> 
```
converter. You can specify the class name of the converter that implments the {@link TypeConverter} interface.It is used to convert the value between component attribute and bean field. Multiple definition is NOT allowed and the later defined would override the previous defined one. Most of the time you don't have to specify this since this DataBinder supports converting most commonly used types. However, if you specify the TypeConverter class name, this DataBinder will new an instance and use it to cast the class.

(Since 3.1) If you specify some tags other than the supported tags, they will be put into an argument Map and is stored as a component's custom attribute (componentScope) with key name "bindingArgs" (no matter annotated in which attribute of the component). e.g. <label id="mylabel" value="@{person.name, answer='yes'}" style="@{person.mystyle, question='no'}">

Then mylabel.getAttribute("bindingArgs") will return a Map with {answer=yes, question=no} two entries

(Since 3.1) We support the "distinct" concept for collection components with "model" attribute(i.e. Grid, Listbox, Comobobox, etc.). You can specify as follows to tell the Data Binder that there might be one same object in multiple entries.

 <grid model="@{persons, distinct=false}" ...> ... </grid>

 <a:bind model="persons; distinct:false"/> <grid ...> ... </grid>

The default value for distinct is "true". However, if you specify distinct=false, the DataBinder will scan the whole ListModel to find out all items with the specified objects (thus worse performance if a big ListModel).

(Since 3.6.2) if you specify some tags other than the supported tags, they will be put into an argument Map and is stored as a component's custom attribute(componentScope) with key name "Xxx_bindingArgs" where the Xxx is the name of the annotated component attribute. e.g.

 <label id="mylabel" value="@{person.name, answer='yes'}" style="@{person.mystyle, question='no'}">

Then mylabel.getAttribute("value_bindingArgs") will return a Map with {answer=yes} entry and mylabel.getAttribute("style_bindingArgs") will return another Map with {question=no} entry.

Since 3.0.0, DataBinder supports validation phase before doing a save. Note that a DataBinder "save" is triggered by a component event as specified on the "save-when" or "save-after" tag. Before doing a save, it first fires an onBindingSave event to each data-binding component and then it fires an onBindingValidate event to the event triggering component before really saving component property contents into bean's property. So application developers get the chance to handle the value validation before saving. In the following example when end user click the "savebtn" button, an "onBindingSave" is first fired to "firtName" and "lastName" textboxes and then an "onBindingValidate" is fired to "savebtn" button. Application developers can register proper event handlers to do what they want to do.

 <textbox id="firstName" value="@{person.firstName, save-when="savebtn.onClick"}" onBindingSave="..."/> <textbox id="lastName" value="@{person.lastName, save-when="savebtn.onClick"}" onBindingSave="..."/> <button id="savebtn" label="save" onBindingValidate="..."/>

Note that the original textbox constraint mechanism is still there. This DataBinder validation phase is an add-on feature that can be applied to all components and attributes that use data binding mechanism.

@since 2.4.0 Supporting @{...} annotations. @since 3.0.0 Supporting multiple events of save-when tag and validation phase. @since 3.1.0 Supporting bidningArgs; suport "distinct" on collection data binding. @since 3.6.1 Support load-after, save-after @since 3.6.2 Support Xxx_bindingArgs @author Henri Chen @see AnnotateDataBinderInit @see DataBinder

Examples of org.zkoss.zkplus.databind.AnnotateDataBinder

Related Classes of org.zkoss.zkplus.databind.AnnotateDataBinder