Is it possible to disable f:event type=“preRenderV

问题:

Is it possible to "disable" triggering of this action when doing postback?

<f:metadata>
    <f:event listener="#{defaultNewQuestionHandler.init}" type="preRenderView" />
</f:metadata>

回答1:

That's not possible with <f:event>. You need to manually check FacesContext#isPostback() inside the listener method.

public void init() {
    if (!FacesContext.getCurrentInstance().isPostback()) {
        // ...
    }
}

In the upcoming JSF 2.2 <f:viewAction> tag, which is supposed to replace this <f:event type="preRenderView"> "workaround", it will however be possible with the onPostback attribute:

<f:viewAction action="#{defaultNewQuestionHandler.init}" onPostback="false" />

Snapshot releases of JSF 2.2 are already available.

See also:

• What's new in JSF 2.2?