将托管Bean实例绑定到复合组件 [英] Binding a managed bean instance to composite component

问题描述

我有一个复合组件(collapsiblePanel).该组件使用可折叠" bean提供切换功能.当我在页面上多次使用同一组件时，该组件的每个实例都绑定到同一bean实例.如何实现类似组件范围的bean?

I have a composite component (collapsiblePanel). The component uses the "collapsible" bean to provide the toggle function. When I use the same component multiple times on a page, each instance of the component is bound to the same bean instance. How Can I achieve something like a component scoped bean?

collapsibleTemp.xhtml:

<cc:interface>
    <cc:attribute name="model" required="true">
        <cc:attribute name="collapsed" required="true" />
        <cc:attribute name="toggle" required="true"
            method-signature="java.lang.String f()" />
    </cc:attribute>
    <cc:actionSource name="toggle" />
    <cc:facet name="header" />
    <cc:facet name="body" />
</cc:interface>
<cc:implementation>
    <h:panelGroup layout="block" styleClass="collapsiblePanel-header">
        <h:commandButton id="toggle" action="#{cc.attrs.model.toggle}"
            styleClass="collapsiblePanel-img"
            image="#{cc.attrs.model.collapsed ? '/resources/images/plus.png' : '/resources/images/minus.png'}" />
        <cc:renderFacet name="header" />
    </h:panelGroup>
    <h:panelGroup layout="block" rendered="#{!cc.attrs.model.collapsed}">
        <cc:insertChildren />
        <cc:renderFacet name="body"></cc:renderFacet>
    </h:panelGroup>
    <h:outputStylesheet library="css" name="components.css" />
</cc:implementation>

后备豆:

@ManagedBean
@ViewScoped
public class Collapsible {

    private boolean collapsed = false;

    public boolean isCollapsed() {
        return collapsed;
    }

    public void setCollapsed(boolean collapsed) {
        this.collapsed = collapsed;
    }

    public String toggle() {
        collapsed = !collapsed;
        return null;
    }

}

使用页面

<h:form id="someid">
    <jl:collapsibletemp id="collapsiblePanel1" model="#{collapsible}">
        <f:facet name="header">
            <h3>
                <h:outputText value="Collapsible information" />
            </h3>
        </f:facet>
        <f:facet name="body">
            <h:outputText value="do something....." />
        </f:facet>
        <p />
    </jl:collapsibletemp>

    <jl:collapsibletemp id="collapsiblePanel2" model="#{collapsible}">
        <f:facet name="header">
            <h3>
                <h:outputText value="Collapsible information" />
            </h3>
        </f:facet>
        <f:facet name="body">
            <h:outputText value="do some tabbing" />
        </f:facet>
        <p />
    </jl:collapsibletemp>

    <jl:collapsibletemp id="collapsiblePanel3" model="#{collapsible}">
        <f:facet name="header">
            <h3>
                <h:outputText value="Collapsible information" />
            </h3>
        </f:facet>
        <f:facet name="body">
            <h:outputText value="notice board" />
        </f:facet>
        <p />
    </jl:collapsibletemp>
</h:form>

推荐答案

您可以使用<cc:interface>的componentType属性来定义支持组件".

You can use the componentType attribute of the <cc:interface> to define a "backing component".

例如

<cc:interface componentType="collapsiblePanel">
    ...
</cc:interface>
<cc:implementation>
    ...
    <h:commandButton action="#{cc.toggle}" ... />
    ...
    <h:panelGroup rendered="#{!cc.collapsed}" ...>
    ...
</cc:implementation>

只有一个com.example.components.CollapsiblePanel

@FacesComponent(value="collapsiblePanel") // To be specified in componentType attribute.
public class CollapsiblePanel extends UINamingContainer { // Important! Must extend UINamingContainer.

    private boolean collapsed;

    public void toggle() {
        collapsed = !collapsed;
    }

    public boolean isCollapsed() {
        collapsed;
    }

}

但是，当您希望拥有多个这些组件时，应在视图中声明它们的物理上独立的实例.如果这需要动态发生，那么您需要使用<c:forEach>生成物理上独立的实例，而不是使用单个组件生成<ui:repeat>.否则，您必须通过Map<String, Boolean>中的客户端ID映射所有collapsed状态.有关示例和更多背景信息，请参见获得每次使用时在复合组件中具有相同的componentType实例

However, when you want to have multiple of those components, then you should declare physically separate instances of them in the view. If this needs to happen dynamically, then you need to use <c:forEach> to generate physically separate instances of them instead of <ui:repeat> with a single component. Otherwise you have to map all collapsed states by the client ID inside a Map<String, Boolean>. See for an example and more background information also Getting same instance of `componentType` in composite component on every use

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