Question

我需要验证我的复合组件中是否传递了可选属性。我怎样才能做到这一点？

<composite:interface>
    <composite:attribute name="attr1" />
    <composite:attribute name="attr2" required="false" /> <!-- means OPTIONAL -->
</composite:interface>
<composite:implementation>
    <!-- How I can verify here whether attr2 is present or not whenever this component is used? -->
</composite:implementation>

为default设置xxx属性为<composite:attribute>并不是我想要的。

Answer 1

您只需检查#{not empty cc.attrs.attr2}是否评估为true。

E.g。在任意组件的rendered属性中：

<composite:implementation>
    <h:panelGroup rendered="#{not empty cc.attrs.attr2}">
        Attribute attr2 is not empty!
    </h:panelGroup>
</composite:implementation>

Answer 2

您可以使用以下方法检查表达式是否存在：

cc.getValueExpression（＆＃39; someAttribute＆＃39）

CpG.T.Test  <- function(betam, pheno){
  R = 50000
  t = numeric(R)
  p = numeric(R)

  for (i in 1:R){
    beta.v <- betam[i, ]
    pheno.v <- pheno

    test <- t.test (beta.v ~ pheno.v)
    t[i] = test$statistic
    p[i] = test$p.value
  }
}

Answer 3

您可以通过以下方式有条件地向组件添加属性：

<c:if><f:attribute>

样品：

<composite:interface>
    <composite:attribute name="label" />
    <composite:attribute name="required" default="false" />
    <composite:attribute name="readonly" default="false" />
    <composite:attribute name="value" />
    <composite:attribute name="title" />
    <composite:attribute name="placeholder" />
    <composite:attribute name="maxlength" type="java.lang.Integer"/>
</composite:interface>
<composite:implementation>
    <p:inputText
      id="field"
      value="#{cc.attrs.value}">
        <c:if test="#{empty cc.attrs.maxLength}">
           <f:attribute name="maxlength" value="#{cc.attrs.maxlength}" />
        </c:if>
    </p:inputText>
</composite:implementation>

我找到了答案：

How not to set an attribute of a component inside a composite component if it is empty?

如何检查复合组件中是否存在可选属性

3 个答案: