8.11. Conversational components and JSF component bindings

Conversational components have one minor limitation: they cannot be used to hold bindings to JSF components. (Generally we recommend avoiding this feature of JSF unless absolutely necessary, since it creates a hard dependency from application logic to the view.) On a postback request, component bindings are updated during the Restore View phase, before the Seam conversation context has been restored.

You can work around this by storing component bindings with an event-scoped component, and injecting this into the requiring conversation-scoped component.

@Name("grid") 
@Scope(ScopeType.EVENT) 
public class Grid { 
    private HtmlPanelGrid htmlPanelGrid; // getters and setters 
    ... 
}

@Name("grid") 
@Scope(ScopeType.EVENT) 
public class Grid { 
    private HtmlPanelGrid htmlPanelGrid; // getters and setters 
    ... 
}

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@Name("gridEditor") 
@Scope(ScopeType.CONVERSATION) 
public class GridEditor { 
    @In(required=false) 
    private Grid grid; 
    ... 
}

@Name("gridEditor") 
@Scope(ScopeType.CONVERSATION) 
public class GridEditor { 
    @In(required=false) 
    private Grid grid; 
    ... 
}

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You are also limited in that a conversation-scoped component cannot be injected into an event-scoped component with a JSF control bound to it. This includes Seam built-in components like facesMessages.

You can also access the JSF component tree with the implicit uiComponent handle. The following example accesses the getRowIndex() of the UIData component that backs the data table during iteration, and prints the current row number:

<h:dataTable id="lineItemTable" var="lineItem" 
   value="#{orderHome.lineItems}"> 
  <h:column> 
    Row: #{uiComponent[&#39;lineItemTable&#39;].rowIndex} 
  </h:column> 
  ... 
</h:dataTable>

<h:dataTable id="lineItemTable" var="lineItem" 
   value="#{orderHome.lineItems}"> 
  <h:column> 
    Row: #{uiComponent[&#39;lineItemTable&#39;].rowIndex} 
  </h:column> 
  ... 
</h:dataTable>

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In this map, JSF UI components are available with their client identifier.

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8.11. Conversational components and JSF component bindings

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