Java JSF 2 - 如何将 Ajax 侦听器方法添加到复合组件接口？
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JSF 2 - How can I add an Ajax listener method to composite component interface?
提问by Jim Tough
I have a JSF 2 composite component that employs some Ajax behavior. I want to add a listenermethod to the <f:ajax>tag inside my composite component, but the listenermethod should be provided as a <composite:attribute>in the <composite:interface>.
我有一个 JSF 2 复合组件，它采用了一些 Ajax 行为。我想添加一个listener方法到<f:ajax>标签我复合组件内部，但listener方法应为提供<composite:attribute>的<composite:interface>。
The <f:ajax>tag inside my composite component is currently hard-coded to a listener like this:
<f:ajax>我的复合组件中的标签目前硬编码到一个监听器，如下所示：
<f:ajax
event="valueChange"
execute="@this"
listener="#{controller.genericAjaxEventLogger}"
render="#{cc.attrs.ajaxRenderTargets}" />
The listener method on the bean has this signature:
bean 上的侦听器方法具有以下签名：
public void genericAjaxEventLogger(AjaxBehaviorEvent event)
throws AbortProcessingException {
// implementation code...
}
I want the composite component to be something like this so the page can supply its own event method, but I can't figure out the correct syntax for the interface.
我希望复合组件是这样的，这样页面就可以提供自己的事件方法，但我无法弄清楚接口的正确语法。
<f:ajax
event="valueChange"
execute="@this"
listener="#{cc.attrs.ajaxEventListener}"
render="#{cc.attrs.ajaxRenderTargets}" />
How can I do this?
我怎样才能做到这一点？
UPDATED WITH SOLUTION:
更新解决方案：
I took the approach suggested by BalusC and it works great. The relevant snippets are:
我采用了 BalusC 建议的方法，效果很好。相关的片段是：
The interface declaration in the composite component
复合组件中的接口声明
<composite:interface>
<composite:attribute
name="myattributeUpdatedEventListener"
method-signature="void listener()"
required="true" />
...
</composite:interface>
The Ajax tag used in my composite component
我的复合组件中使用的 Ajax 标记
<f:ajax
event="valueChange"
execute="@this"
listener="#{cc.attrs.myattributeUpdatedEventListener}"
render="#{cc.attrs.ajaxRenderTargets}" />
The place in my page where I use the composite component
我在页面中使用复合组件的地方
<h:form>
<compcomp:myCompositeComponent
myattributeUpdatedEventListener="#{myBackingBean.updatedEventListenerXYZ}" />
</h:form>
And the method on my backing bean
以及我的支持 bean 上的方法
public void updatedEventListenerXYZ() {
// do something here...
}
采纳答案by BalusC
If you canget rid of the AjaxBehaviorEventargument,
如果你能摆脱AjaxBehaviorEvent争论，
public void genericAjaxEventLogger() {
// ...
}
then you can use
然后你可以使用
<cc:attribute name="ajaxEventListener" method-signature="void listener()" />
If the argument is mandatory (for logging?), then you need to re-specify the attribute as follows
如果参数是强制性的（用于日志记录？），那么您需要重新指定属性如下
<cc:attribute name="ajaxEventListener" method-signature="void listener(javax.faces.event.AjaxBehaviorEvent)" />
However, this does here not work as expected with
但是，这在这里不能按预期工作
<f:ajax listener="#{cc.attrs.ajaxEventListener}" />
on GF 3.1 + Mojarra 2.1.1:
在 GF 3.1 + Mojarra 2.1.1 上：
SEVERE: javax.faces.FacesException: wrong number of arguments
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:89)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:409)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1534)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:281)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:98)
at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:91)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:162)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:326)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:227)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:170)
at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:822)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:719)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1013)
at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:225)
at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.IllegalArgumentException: wrong number of arguments
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.sun.el.parser.AstValue.invoke(AstValue.java:234)
at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:297)
at com.sun.faces.facelets.el.ContextualCompositeMethodExpression.invoke(ContextualCompositeMethodExpression.java:177)
at com.sun.faces.facelets.tag.TagAttributeImpl$AttributeLookupMethodExpression.invoke(TagAttributeImpl.java:450)
at com.sun.faces.facelets.tag.jsf.core.AjaxBehaviorListenerImpl.processAjaxBehavior(AjaxHandler.java:447)
at javax.faces.event.AjaxBehaviorEvent.processListener(AjaxBehaviorEvent.java:113)
at javax.faces.component.behavior.BehaviorBase.broadcast(BehaviorBase.java:102)
at javax.faces.component.UIComponentBase.broadcast(UIComponentBase.java:760)
at javax.faces.component.UICommand.broadcast(UICommand.java:300)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:794)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1259)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
... 28 more
I'm not sure if this is a bug or not. For that I'd need to invest some more time to naildown it. However, it was workaroundable by creating a backing component which gets the MethodExpressionfrom the attributes and invokes with the right number of arguments. Here's a complete kickoff example:
我不确定这是否是一个错误。为此，我需要投入更多时间来确定它。但是，它可以通过创建一个MethodExpression从属性中获取并使用正确数量的参数调用的支持组件来解决。这是一个完整的启动示例：
<ui:component
xmlns:f="http://java.sun.com/jsf/core"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:cc="http://java.sun.com/jsf/composite"
xmlns:ui="http://java.sun.com/jsf/facelets"
>
<cc:interface componentType="testCC">
<cc:attribute name="ajaxEventListener" method-signature="void listener(javax.faces.event.AjaxBehaviorEvent)" />
</cc:interface>
<cc:implementation>
<h:commandButton value="Submit">
<f:ajax listener="#{cc.ajaxEventListener}" />
</h:commandButton>
</cc:implementation>
</ui:component>
with
和
package com.example;
import javax.el.MethodExpression;
import javax.faces.component.FacesComponent;
import javax.faces.component.UINamingContainer;
import javax.faces.context.FacesContext;
import javax.faces.event.AjaxBehaviorEvent;
@FacesComponent(value="testCC")
public class TestCC extends UINamingContainer {
public void ajaxEventListener(AjaxBehaviorEvent event) {
FacesContext context = FacesContext.getCurrentInstance();
MethodExpression ajaxEventListener = (MethodExpression) getAttributes().get("ajaxEventListener");
ajaxEventListener.invoke(context.getELContext(), new Object[] { event });
}
}
Regardless, I believe that the backing component puts doors open for new ways to achieve the functional requirement you have had in mind anyway ;)
无论如何，我相信支持组件为新方法打开了大门，以实现您所想到的功能需求；)
回答by Jason
Here is an example on how to use the interface to set an attribute and reference it within the implementation. You must define the method-signature of the method that will be called. This informs the composite component handler that there is a method value, rather than a value expression, contained in the #{cc.attrs.ajaxEventListener} expression.
下面是一个关于如何使用接口设置属性并在实现中引用它的示例。您必须定义将被调用的方法的方法签名。这会通知复合组件处理程序，#{cc.attrs.ajaxEventListener} 表达式中包含一个方法值，而不是一个值表达式。
<cc:interface name="composite-comp"
<cc:attribute required="true" name="ajaxEventListener"
method-signature="void f1(javax.faces.event.AjaxBehaviorEvent)" />
<cc:attribute required="true" name="ajaxRenderTargets" />
</cc:interface>
<cc:implementation>
.
.
.
<f:ajax event="valueChange" execute="@this"
listener="#{cc.attrs.ajaxEventListener}"
render="#{cc.attrs.ajaxRenderTargets}" />
</cc:implementation>
