<rt id="bn8ez"></rt>
<label id="bn8ez"></label>

  • <span id="bn8ez"></span>

    <label id="bn8ez"><meter id="bn8ez"></meter></label>

    Knight of the round table

    wansong

    Selecting from a list of entities

    <rich:pickList value="#{manageCountryGroup.selectedCountries}" sourceListWidth="200" targetListWidth="200">
                  <s:selectItems value="#{availableCountriesQuery.resultList}" var="c" label="#{c.name}" itemValue="#{c}" >       
                    </s:selectItems>
                    <s:convertEntity/>
                  <a4j:support action="#" event="onlistchanged" reRender="cgManagementPanel" ajaxSingle="true" />
                </rich:pickList>


    Selecting from a list of entities

    See http://docs.jboss.org/seam/latest/reference/en/html/controls.html

    • Use <s:selectItems> to produce a list of labeled select items from a list of entities.
    • Use <s:convertEntity> to map back and forth between the select items and the actual entity values. This is what allows you to map the value of the <h:selectOneMenu> directly to the property of the referencing entity (e.g. a property that is a many-to-one).
    <h:selectOneMenu value="#{person.continent}" required="true">                        (1)

    <s:selectItems value="#{continents.resultList}" var="continent" (2)

    label="#{continent.name}" noSelectionLabel="Please Select..."/>

    <s:convertEntity /> (3)

    </h:selectOneMenu>

    1. person is an entity that has been outjected into the conversation. It has a 'continent' property which is many-to-one association with another entity.
    2. continents is a Seam application framework 'query' object. This 'query' object should probably use a Seam-managed EntityManager because we want have the Hibernate session-in-view behavior so we don't get lazy initialization exceptions when rendering the labels, etc.
    3. s:convertEntity will convert the Continent entities into values for the HTML select, and vice versa.

    Tips

    1. To avoid LazyInitializationExceptions and/or writing extra code in your EJB/Controller bean to initialize objects, use session in view.
    2. For required fields, put required="true" on the selectOneMenu and override javax.faces.component.UIInput.REQUIRED in messages.properties (see Standard Faces Error Messages).

    Select from an enum

    This works just like selecting an entity, but <s:convertEnum/> is used instead.


    XHTML:

    <h:selectOneMenu id="marketStatus" value="#{person.status}"         (1)

    required="true">

    <s:selectItems value="#{enumLists.statusArray}" var="status" (2)

    label="#{status}"

    noSelectionLabel="Select a status..."/>

    <s:convertEnum/>

    </h:selectOneMenu>

    EnumLists.java:

    @Name("enumLists")

    @Scope(ScopeType.STATELESS)

    public class EnumLists

    {

    public Status[] getStatusArray()

    {

    return Status.values();

    }

    }

    1. person is an entity that has been outjected into the conversation. It has a 'status' property which is an enum.
    2. We need to expose the values of the enum as a list or an array, so we make a stateless POJO component with getters that returns arrays for various enums called enumLists.

    Multi-select from an enum

    Here we use a selectManyCheckbox.


    <h:selectManyCheckbox id="roles" 

    layout="pageDirection" value="#{person.roles}"

    required="true">

    <s:selectItems value="#{enumLists.roleArray}" var="role"

    label="#{role}"/>

    <s:convertEnum/>

    </h:selectManyCheckbox>

    Unfortunately, Seam's convertEnum can't handle multi selects yet. This example will yeild a strange exception:

    java.lang.IllegalArgumentException: java.util.List is not an enum type

    Luckily, it's very easy to create custom converter tags with Facelets. Here is the converter class that handles both ordinary enums and multi-selects:

    package eg;



    import javax.faces.component.*;

    import javax.faces.context.*;

    import javax.faces.convert.*;

    import javax.faces.el.ValueBinding;

    import java.util.List;

    import java.util.Collection;



    /**

    * Converter for enum multi-selects.

    * <br>User: Joshua Davis

    * Date: May 16, 2007

    * Time: 7:25:58 AM

    */

    public class EnumListConverter implements Converter

    {

    @SuppressWarnings({"unchecked"})

    public Object getAsObject(FacesContext context,

    UIComponent comp,

    String value)

    throws ConverterException

    {

    ValueBinding binding = comp.getValueBinding("value");

    Class enumType = binding.getType(context);

    if (enumType.isEnum()) // Single enum?

    return Enum.valueOf(enumType, value);

    else // List of enums.

    {

    // Find the s:selectItems so we can get the enum.

    List children = comp.getChildren();

    for (Object child : children)

    {

    if (child instanceof UIComponent)

    {

    UIComponent c = (UIComponent) child;

    ValueBinding b = c.getValueBinding("value");

    Class t = b.getType(context);

    // Array of enums: use the component type.

    if (t.isArray() && t.getComponentType().isEnum())

    {

    t = t.getComponentType();

    return Enum.valueOf(t,value);

    }

    else

    {

    Object v = b.getValue(context);

    // Collection of enum values, get the type of the first element.

    if (v instanceof Collection)

    {

    t = ((Collection) v).iterator().next().getClass();

    return Enum.valueOf(t,value);

    }

    }

    }

    }

    throw new ConverterException("Unable to find selectItems with enum values!");

    }

    }



    public String getAsString(FacesContext context,

    UIComponent component,

    Object object)

    throws ConverterException

    {

    if (object == null) {

    return null;

    }



    return ((Enum) object).name();

    }



    }

    Retrieved from "


    posted on 2009-04-14 11:01 w@ns0ng 閱讀(994) 評論(0)  編輯  收藏 所屬分類: Jboss Seam

    主站蜘蛛池模板: 日本高清免费中文在线看| 久久精品a亚洲国产v高清不卡| 亚洲AV无码一区二区三区人 | 欧洲亚洲综合一区二区三区| 欧洲精品成人免费视频在线观看| 亚洲精品影院久久久久久| 8x网站免费入口在线观看| 国产亚洲蜜芽精品久久| 日日夜夜精品免费视频| 国产精品国产亚洲区艳妇糸列短篇 | 免费在线观看毛片| 免费在线观看自拍性爱视频| 亚洲国产精品综合久久网络| 久久亚洲精品成人| 日韩内射激情视频在线播放免费 | 免费无码午夜福利片 | XXX2高清在线观看免费视频| 91免费在线播放| 亚洲人成图片网站| 日本黄色免费观看| 国产精品成人免费观看| 亚洲午夜精品一区二区| 欧美在线看片A免费观看| 美女扒开屁股让男人桶爽免费| 中文字幕亚洲日本岛国片| 一级成人a毛片免费播放| 亚洲夂夂婷婷色拍WW47| 亚洲精品无码99在线观看| 亚洲色偷偷色噜噜狠狠99| 可以免费观看一级毛片黄a| 中文字幕免费在线看电影大全| 久久精品国产亚洲AV嫖农村妇女| 色se01短视频永久免费| 免费的黄网站男人的天堂| 亚洲成人中文字幕| 精品久久洲久久久久护士免费| 中文字幕免费观看全部电影| 亚洲一区二区三区在线观看蜜桃| 亚洲国产高清在线一区二区三区| 日韩精品内射视频免费观看 | 日韩亚洲一区二区三区|