How to make a grid of JSF composite component?

2023-02-27 03:34 问答作者：

I have lot's of outputLabel and inputText pairs in panelGrids

<h:panelGrid columns="2">
  <h:outputLabel value="label1" for="inputId1"/>
  <h:inputText id="i开发者_运维知识库nputId1/>

  <h:outputLabel value="label2" for="inputId2"/>
  <h:inputText id="inputId2/>

  ...
</h:panelGrid>

I want to have some behaviour for all of them: like same validation or same size for every inputText. So I have created a composite component which just includes an outputLabel and and an inputText

<my:editField value="field1"/>
<my:editField value="field2"/>

But now when I put them in a gridPanel, they do not get aligned depending on the length of the label text. I understand why, but I don't know how to work around.

A composite component gets indeed rendered as a single component. You want to use a Facelet tag file instead. It gets rendered exactly as whatever its output renders. Here's a kickoff example assuming that you want a 3-column form with a message field in the third column.

Create tag file in /WEB-INF/tags/input.xhtml (or in /META-INF when you want to provide tags in a JAR file which is to be included in /WEB-INF/lib).

<ui:composition
    xmlns:c="http://java.sun.com/jsp/jstl/core"
    xmlns:f="http://java.sun.com/jsf/core"
    xmlns:h="http://java.sun.com/jsf/html"
    xmlns:ui="http://java.sun.com/jsf/facelets">

    <c:set var="id" value="#{not empty id ? id : (not empty property ? property : action)}" />
    <c:set var="required" value="#{not empty required and required}" />

    <c:choose>
        <c:when test="#{type != 'submit'}">
            <h:outputLabel for="#{id}" value="#{label}&#160;#{required ? '*&#160;' : ''}" />
        </c:when>
        <c:otherwise>
            <h:panelGroup />
        </c:otherwise>
    </c:choose>

    <c:choose>
        <c:when test="#{type == 'text'}">
            <h:inputText id="#{id}" value="#{bean[property]}" label="#{label}" required="#{required}">
                <f:ajax event="blur" render="#{id}-message" />
            </h:inputText>
            <h:message id="#{id}-message" for="#{id}" />
        </c:when>
        <c:when test="#{type == 'password'}">
            <h:inputSecret id="#{id}" value="#{bean[property]}" label="#{label}" required="#{required}">
                <f:ajax event="blur" render="#{id}-message" />
            </h:inputSecret>
            <h:message id="#{id}-message" for="#{id}" />
        </c:when>
        <c:when test="#{type == 'select'}">
            <h:selectOneMenu id="#{id}" value="#{bean[property]}" label="#{label}" required="#{required}">
                <f:selectItems value="#{options.entrySet()}" var="entry" itemValue="#{entry.key}" itemLabel="#{entry.value}" />
                <f:ajax event="change" render="#{id}-message" />
            </h:selectOneMenu>
            <h:message id="#{id}-message" for="#{id}" />
        </c:when>
        <c:when test="#{type == 'submit'}">
            <h:commandButton id="#{id}" value="#{label}" action="#{bean[action]}" />
            <h:message id="#{id}-message" for="#{id}" />
        </c:when>
        <c:otherwise>
            <h:panelGroup />
            <h:panelGroup />
        </c:otherwise>            
    </c:choose>
</ui:composition>

Define it in /WEB-INF/example.taglib.xml (or in /META-INF when you want to provide tags in a JAR file which is to be included in /WEB-INF/lib):

<?xml version="1.0" encoding="UTF-8"?>
<facelet-taglib 
    xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-facelettaglibrary_2_0.xsd"
    version="2.0">
    <namespace>http://example.com/jsf/facelets</namespace>
    <tag>
        <tag-name>input</tag-name>
        <source>tags/input.xhtml</source>
    </tag>
</facelet-taglib>

Declare the taglib usage in /WEB-INF/web.xml (this is not needed when the tags are provided by a JAR file which is included in /WEB-INF/lib! JSF will auto-load all *.taglib.xml files from /META-INF).

<context-param>
    <param-name>javax.faces.FACELETS_LIBRARIES</param-name>
    <param-value>/WEB-INF/example.taglib.xml</param-value>
</context-param>

(multiple taglib files can be separated by semicolon ;)

Finally just declare it in your main page templates.

<!DOCTYPE html>
<html lang="en"
    xmlns="http://www.w3.org/1999/xhtml"
    xmlns:f="http://java.sun.com/jsf/core"
    xmlns:h="http://java.sun.com/jsf/html"
    xmlns:ui="http://java.sun.com/jsf/facelets"
    xmlns:my="http://example.com/jsf/facelets"
>
    <h:head>
        <title>Facelet tag file demo</title>
    </h:head>
    <h:body>
        <h:form>
            <h:panelGrid columns="3">
                <my:input type="text" label="Username" bean="#{bean}" property="username" required="true" />
                <my:input type="password" label="Password" bean="#{bean}" property="password" required="true" />
                <my:input type="select" label="Country" bean="#{bean}" property="country" options="#{bean.countries}" />
                <my:input type="submit" label="Submit" bean="#{bean}" action="submit" />
            </h:panelGrid>
        </h:form>
    </h:body>
</html>

(the #{bean.countries} should return a Map<String, String> with country codes as keys and country names as values)