Enums 从Vaadin 7中的枚举生成OptionGroup(单选按钮)?
我有一个Java枚举,带有所需显示文本的getter。如何使用此选项填充Vaadin 7中的OptionGroup?以下是在Vaadin 7中执行此操作的三种方法:Enums 从Vaadin 7中的枚举生成OptionGroup(单选按钮)?,enums,vaadin,vaadin7,Enums,Vaadin,Vaadin7,我有一个Java枚举,带有所需显示文本的getter。如何使用此选项填充Vaadin 7中的OptionGroup?以下是在Vaadin 7中执行此操作的三种方法: 我构建的一个类,EnumBackedOptionGroup。Vaadin 7中的OptionGroup的一个子类 用你自己的短而甜美的方式滚动 以更灵活的方式推出您自己的产品 OptionGroup的子类 下面是我编写的OptionGroup的一个新子类的源代码 package com.basilbourque; import
- 我构建的一个类,
。Vaadin 7中的EnumBackedOptionGroup
的一个子类OptionGroup
- 用你自己的短而甜美的方式滚动
- 以更灵活的方式推出您自己的产品
OptionGroup的子类
下面是我编写的OptionGroup
的一个新子类的源代码
package com.basilbourque;
import com.vaadin.ui.OptionGroup;
import java.util.Arrays;
import java.util.Collection;
import java.util.function.Function;
import org.slf4j.LoggerFactory;
/**
* A subclass of the Vaadin 7 OptionGroup (radio buttons or bunch of checkboxes) widget, taking as its set of options
* the instances of an Enum.
*
* In canonical usage, pass the class of your Enum and a reference to the method to be called for obtaining a textual
* label for display to the user.
*
* Alternatively, if your Enum overrides the `toString` method, you may pass only the class of the Enum without a
* Function. This approach is not recommended per the class documentation which explains `toString` should only be used
* for debugging message. Nevertheless, some people override `toString` to provide a user-readable label, so we support
* this.
*
* Even if your Enum does not override `toString` you may choose to omit passing the Function argument. As a default,
* the Enum’s built-in `toString` method will be called, returning the "name" of the Enum’s instance. This is handy for
* quick-and-dirty prototyping. Again, neither I nor the class doc recommend this approach for serious work.
*
* If you want to display a subset of your enum’s instances rather than all, pass a Collection.
*
* This source code available under terms of ISC License. https://en.wikipedia.org/wiki/ISC_license
*
* Copyright (c) 2015, Basil Bourque
* Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby
* granted, provided that the above copyright notice and this permission notice appear in all copies. THE SOFTWARE IS
* PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT,
* OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
* SOFTWARE.
*
* @author Basil Bourque
* @version 2015-08-27T21:00:00Z
* @since 2015-08-27T21:00:00Z
*/
public class EnumBackedOptionGroup<T extends Enum> extends OptionGroup
{
final org.slf4j.Logger logger = LoggerFactory.getLogger( this.getClass() );
/**
* Constructor. The usual constructor for automatically detecting all the instances of an enum for use as the
* options in a Vaadin 7 OptionGroup. Pass a function to be called for providing each option’s displayed labeling.
*
* Example usage:
*
* myRadios = new EnumBackedOptionGroup<DogBreed>( "Choose breed:" , DogBreed.class , DogBreed :: getTitle );
*
* @param caption
* @param enumClass
* @param f
*/
public EnumBackedOptionGroup ( final String caption , final Class<T> enumClass , final Function<T , String> f ) {
super( caption );
Function<T , String> func = f;
// If passed a null for the Function, fallback to using 'toString'.
if ( func == null ) {
func = T -> T.toString();
}
this.buildAndAssignCaptions( enumClass , func );
}
/**
* Constructor. Similar to usual constructor, but here you may additionally pass a Collection of the subset of Enum
* instances.
*
* For use where business logic dictates that you give only some of the Enum values an options rather than all of
* them. The omitted options are effectively hidden from the user.
*
* @param caption
* @param enumClass
* @param enumValues
* @param f
*/
public EnumBackedOptionGroup ( final String caption , final Class<T> enumClass , final Collection<T> enumValues , final Function<T , String> f ) {
super( caption );
Function<T , String> func = f;
// If passed a null for the Function, fallback to using 'toString'.
if ( func == null ) {
func = T -> T.toString();
}
Collection<T> ev = enumValues;
// Handle where calling method passed us a null or empty collection.
if ( ( ev == null ) || ev.isEmpty() ) {
this.buildAndAssignCaptions( enumClass , f ); // Fallback to assiging all the instances of enum as options in our OptionGroup.
} else {
this.addItems( enumValues ); // Add the passed subset of instances of the enum as items backing our OptionGroup.
this.assignCaptions( enumValues , f );
}
}
/**
* Constructor. Similar to the usual constructor, but omits the method for providing on-screen labeling. Instead
* uses the 'toString' method defined either explicitly in the Enum subclass or implicitly calls to the Enum class’
* own 'toString'.
*
* Not recommended, as the Enum documentation strongly suggests the 'toString' method on an Enum be used only for
* debugging. Nevertheless this is handy for quick-and-dirty prototyping.
*
* @param caption
* @param enumClass
*/
public EnumBackedOptionGroup ( final String caption , final Class<T> enumClass ) {
super( caption );
// User passed no Function to call for getting the title. So fallback to using 'toString'.
this.buildAndAssignCaptions( enumClass , T -> T.toString() );
}
// Helper method. (sub-routine)
// Extracts all the instances of the enum, and uses them as options in our OptionGroup.
// Also assigns each option a labeling using String returned by passed method to be called for each instance of enum.
private void buildAndAssignCaptions ( final Class<T> enumClass , final Function<T , String> f ) {
if ( enumClass.isEnum() ) { // This check may be unnecessary with Generics code "<T extends Enum>" at top of this class.
Collection<T> enumValues = Arrays.asList( enumClass.getEnumConstants() );
this.addItems( enumValues ); // Add all the instances of the enum as items backing our OptionGroup.
this.assignCaptions( enumValues , f );
} else {
// Else the passed class is not an enum.
// This case should not be possible because of the Generics marked on this class "<T extends Enum>".
logger.error( "Passed a class that is not a subclass of Enum. Message # f2098672-ab47-47fe-b720-fd411411052e." );
throw new IllegalArgumentException( "Passed a class that is not a subclass of Enum." );
}
}
// Helper method. (sub-routine)
// Assigns each option a labeling using String returned by passed method to be called for each instance of enum
private void assignCaptions ( Collection<T> enumValues , final Function<T , String> f ) {
for ( T option : enumValues ) {
// For each option in our OptionGroup, determine and set its title, the label displayed for the user next to each radio button or checkbox.
// To determine the label (the second argument), we invoke the passed method which must return a String. Using Lambda syntax.
this.setItemCaption( option , f.apply( option ) );
}
}
}
我之所以能完成这门课,是因为我的问题是由
要使用此EnumBackedGroupOption
类,请传递其类和该标题呈现方法的方法引用。这需要Java 8中的新版本。但是不需要掌握你对Lambda的理解,只需遵循你在这里看到的模式
OptionGroup optionGroup = new EnumBackedOptionGroup<DogBreed>( "Choose Breed:" , DogBreed.class , DogBreed :: getTitle );
有时,您可能不希望在OptionGroup中使用所有枚举实例值。如果是,请使用中介绍的隐式方法values
提取这些实例的集合。去掉不需要的。请注意,我们如何从Arrays.asList
的输出实例化一个新的ArrayList
,以允许此修改。然后将该集合传递给EnumBackedOptionGroup
的另一个构造函数
您可以使用toString
作为表示标签,将null作为最后一个参数传递
您可能可以使用或而不是.values
,但我没有这方面的经验
Collection<T> enumValues = new ArrayList( Arrays.asList( SaySo.values() ) );
enumValues.remove( SaySo.MAYBE );
OptionGroup optionGroup = new EnumBackedOptionGroup<SaySo>( "Says you:" , SaySo.class , null );
通过添加构造函数,我们可以向每个枚举实例传递所需的显示文本,然后将该文本存储在私有成员字符串变量中
简捷的方法
如果在确定显示文本时没有特别的工作要做,只需重写该方法以返回存储的显示文本
我不推荐这种方法。仅当要创建特殊值以在调试工作中显示给程序员时,建议重写toString
。然而,我确实尝试过这种方法,它确实有效
公共字符串toString()
…此方法可能会被重写,尽管它通常不是必需的或可取的。当存在更“程序员友好”的字符串形式时,枚举类型应重写此方法
toString
方法的完整示例
带有嵌套枚举的Person
类
package com.example.vaadinradiobuttons;
import java.util.ArrayList;
import java.util.List;
/**
*
* @author Basil Bourque
*/
public class Person {
// Members
String name;
Person.VITAL_STATUS vitalStatus;
public enum VITAL_STATUS {
LIVING( "Alive and Kicking" ),
DECEASED( "Dead" ),
UNKNOWN( "DUNNO" );
private String captionText;
VITAL_STATUS ( String t ) {
this.captionText = t;
}
@Override
public String toString () {
return this.captionText;
}
}
// Constructor
public Person ( String nameArg , VITAL_STATUS vitalStatusArg ) {
this.name = nameArg;
this.vitalStatus = vitalStatusArg;
}
}
还有一个小小的Vaadin 7.4.3应用程序,它使用嵌套枚举填充选项组。查找示例的注释//核心。
以查看重要的行
package com.example.vaadinradiobuttons;
import javax.servlet.annotation.WebServlet;
import com.vaadin.annotations.Theme;
import com.vaadin.annotations.VaadinServletConfiguration;
import com.vaadin.annotations.Widgetset;
import com.vaadin.data.Property;
import com.vaadin.server.VaadinRequest;
import com.vaadin.server.VaadinServlet;
import com.vaadin.ui.OptionGroup;
import com.vaadin.ui.UI;
import com.vaadin.ui.VerticalLayout;
import java.util.Arrays;
import java.util.Collection;
/**
*
*/
@Theme ( "mytheme" )
@Widgetset ( "com.example.vaadinradiobuttons.MyAppWidgetset" )
public class MyUI extends UI {
@Override
protected void init ( VaadinRequest vaadinRequest ) {
final VerticalLayout layout = new VerticalLayout();
layout.setMargin( true );
setContent( layout );
// Core of example.
Collection<Person.VITAL_STATUS> v = Arrays.asList( Person.VITAL_STATUS.values() );
OptionGroup radios = new OptionGroup( "Vital Status :" , v );
radios.setImmediate( true );
radios.addValueChangeListener( ( Property.ValueChangeEvent event ) -> {
Person.VITAL_STATUS vitalStatus = ( Person.VITAL_STATUS ) event.getProperty().getValue();
System.out.println( "User selected a vital status name: " + vitalStatus.name() + ", labeled: " + vitalStatus.toString() );
} );
layout.addComponent( radios );
}
@WebServlet ( urlPatterns = "/*" , name = "MyUIServlet" , asyncSupported = true )
@VaadinServletConfiguration ( ui = MyUI.class , productionMode = false )
public static class MyUIServlet extends VaadinServlet {
}
}
这很有效。我希望它在瓦丁6号和7号都能用
BeanItemContainer
方法的完整示例
让我们调整上面部分所示的示例Person
和Vaadin应用程序
在Person
类中,将toString
方法替换为JavaBeans属性getter,getCaptionText
。此方法的名称可以是任何名称,只要它与下面Vaadin应用程序中看到的对setItemCaptionPropertyId
的调用相匹配
package com.example.vaadinradiobuttons;
import java.util.ArrayList;
import java.util.List;
/**
*
* @author Basil Bourque
*/
public class Person {
// Members
String name;
Person.VITAL_STATUS vitalStatus;
public enum VITAL_STATUS {
LIVING( "Alive and Kicking" ),
DECEASED( "Dead" ),
UNKNOWN( "DUNNO" );
private String captionText;
static public String CAPTION_TEXT_PROPERTY_NAME = "captionText"; //
VITAL_STATUS ( String t ) {
this.captionText = t;
}
// JavaBeans Property getter.
public String getCaptionText () {
return this.captionText;
}
}
// Constructor
public Person ( String nameArg , VITAL_STATUS vitalStatusArg ) {
this.name = nameArg;
this.vitalStatus = vitalStatusArg;
}
}
Vaadin应用程序更改为使用BeanItemContainer
。通过调用setItemCaptionPropertyId
,您可以指定该容器中的哪些属性应用作要显示的文本
package com.example.vaadinradiobuttons;
import javax.servlet.annotation.WebServlet;
import com.vaadin.annotations.Theme;
import com.vaadin.annotations.VaadinServletConfiguration;
import com.vaadin.annotations.Widgetset;
import com.vaadin.data.Property;
import com.vaadin.data.util.BeanItemContainer;
import com.vaadin.server.VaadinRequest;
import com.vaadin.server.VaadinServlet;
import com.vaadin.ui.OptionGroup;
import com.vaadin.ui.UI;
import com.vaadin.ui.VerticalLayout;
import java.util.Arrays;
import java.util.Collection;
/**
*
*/
@Theme ( "mytheme" )
@Widgetset ( "com.example.vaadinradiobuttons.MyAppWidgetset" )
public class MyUI extends UI {
@Override
protected void init ( VaadinRequest vaadinRequest ) {
final VerticalLayout layout = new VerticalLayout();
layout.setMargin( true );
setContent( layout );
// Core of example.
Collection<Person.VITAL_STATUS> v = Arrays.asList( Person.VITAL_STATUS.values() );
BeanItemContainer<Person.VITAL_STATUS> bic = new BeanItemContainer<>( Person.VITAL_STATUS.class , v );
OptionGroup radios = new OptionGroup( "Vital Status :" , bic );
radios.setItemCaptionPropertyId(Person.VITAL_STATUS.CAPTION_TEXT_PROPERTY_NAME ); // …or… ( "captionText" );
radios.setImmediate( true );
radios.addValueChangeListener( ( Property.ValueChangeEvent event ) -> {
Person.VITAL_STATUS vitalStatus = ( Person.VITAL_STATUS ) event.getProperty().getValue();
System.out.println( "User selected a vital status name: " + vitalStatus.name() + ", labeled: " + vitalStatus.toString() );
} );
layout.addComponent( radios );
}
@WebServlet ( urlPatterns = "/*" , name = "MyUIServlet" , asyncSupported = true )
@VaadinServletConfiguration ( ui = MyUI.class , productionMode = false )
public static class MyUIServlet extends VaadinServlet {
}
}
package com.example.vaadinradiobuttons;
导入javax.servlet.annotation.WebServlet;
导入com.vaadin.annotations.Theme;
导入com.vaadin.annotations.VaadinServletConfiguration;
导入com.vaadin.annotations.Widgetset;
导入com.vaadin.data.Property;
导入com.vaadin.data.util.BeanItemContainer;
导入com.vaadin.server.vaadin请求;
导入com.vaadin.server.VaadinServlet;
导入com.vaadin.ui.OptionGroup;
导入com.vaadin.ui.ui;
导入com.vaadin.ui.VerticalLayout;
导入java.util.array;
导入java.util.Collection;
/**
*
*/
@主题(“神话主题”)
@Widgetset(“com.example.vaadinradiobuttons.MyAppWidgetset”)
公共类MyUI扩展了MyUI{
@凌驾
受保护的void init(VaadinRequest VaadinRequest){
最终垂直布局=新建垂直布局();
布局。设置页边距(真);
设置内容(布局);
//榜样的核心。
Collection v=Arrays.asList(Person.VITAL_STATUS.values());
BeanItemContainer bic=新的BeanItemContainer(Person.VITAL_STATUS.class,v);
OptionGroup无线电=新的OptionGroup(“生命状态:”,bic);
radios.setItemCaptionPropertyId(Person.VITAL_STATUS.CAPTION_TEXT_PROPERTY_NAME);/…或…(“captionText”);
无线电。设置立即(真);
radios.addValueChangeListener((Property.ValueChangeEvent事件)->{
Person.VITAL_STATUS vitalStatus=(Person.VITAL_STATUS)event.getProperty().getValue();
System.out.println(“用户选择了一个重要状态名称:+vitalStatus.name()+”,标记为:+vitalStatus.toString());
} );
布局。添加组件(无线电);
}
@WebServlet(urlPatterns=“/*”,name=“MyUIServlet”,asyncSupported=true)
@VaadinServletConfiguration(ui=MyUI.class,productionMode=false)
公共静态类MyUIServlet扩展了VaadinServlet{
}
}
Viritin
,用于Vaadin,有一个非常方便的字段,名为EnumSelect
。它可以从编辑的特性中自动检测可用特性。您也可以只传递一个策略,在UI上显示为标题
基本用法
EnumSelect<AddressType> select = new EnumSelect<AddressType>()
.withSelectType(OptionGroup.class);
select.setStyleName(ValoTheme.OPTIONGROUP_HORIZONTAL);
// The Enum type is detected when the edited property is bound to select
// This typically happens via basic bean binding, but here done manually.
ObjectProperty objectProperty = new ObjectProperty(AddressType.Home);
select.setPropertyDataSource(objectProperty);
// Alternatively, if not using databinding at all, you could just use
// basic TypedSelect, or the method from it
// select.setOptions(AddressType.values());
EnumSelect=newenumselect()
.带有SelectType(OptionGroup.class);
选择.setStyleName(ValoTheme.OPTIONGROUP_水平);
//当已编辑的属性绑定到“选择”时,将检测枚举类型
//这通常是通过基本bean绑定实现的,但这里是手动完成的。
ObjectProperty=新的ObjectProperty(AddressType.Home);
select.setPropertyDataSource(objectProperty);
//交替
package com.example.vaadinradiobuttons;
import javax.servlet.annotation.WebServlet;
import com.vaadin.annotations.Theme;
import com.vaadin.annotations.VaadinServletConfiguration;
import com.vaadin.annotations.Widgetset;
import com.vaadin.data.Property;
import com.vaadin.server.VaadinRequest;
import com.vaadin.server.VaadinServlet;
import com.vaadin.ui.OptionGroup;
import com.vaadin.ui.UI;
import com.vaadin.ui.VerticalLayout;
import java.util.Arrays;
import java.util.Collection;
/**
*
*/
@Theme ( "mytheme" )
@Widgetset ( "com.example.vaadinradiobuttons.MyAppWidgetset" )
public class MyUI extends UI {
@Override
protected void init ( VaadinRequest vaadinRequest ) {
final VerticalLayout layout = new VerticalLayout();
layout.setMargin( true );
setContent( layout );
// Core of example.
Collection<Person.VITAL_STATUS> v = Arrays.asList( Person.VITAL_STATUS.values() );
OptionGroup radios = new OptionGroup( "Vital Status :" , v );
radios.setImmediate( true );
radios.addValueChangeListener( ( Property.ValueChangeEvent event ) -> {
Person.VITAL_STATUS vitalStatus = ( Person.VITAL_STATUS ) event.getProperty().getValue();
System.out.println( "User selected a vital status name: " + vitalStatus.name() + ", labeled: " + vitalStatus.toString() );
} );
layout.addComponent( radios );
}
@WebServlet ( urlPatterns = "/*" , name = "MyUIServlet" , asyncSupported = true )
@VaadinServletConfiguration ( ui = MyUI.class , productionMode = false )
public static class MyUIServlet extends VaadinServlet {
}
}
BeanItemContainer<SomeClass.CRITTER_FILTER> radiosBic = new BeanItemContainer<SomeClass.CRITTER_FILTER>( SomeClass.CRITTER_FILTER.class );
radiosBic.addAll( Arrays.asList( SomeClass.CRITTER_FILTER.values() ) ); // Convert array of values to a `Collection` object.
this.filterRadios = new OptionGroup( "Critter Filter:" , radiosBic );
this.filterRadios.setMultiSelect( false ); // Radio buttons are single-select.
this.filterRadios.setItemCaptionMode( AbstractSelect.ItemCaptionMode.PROPERTY );
this.filterRadios.setItemCaptionPropertyId( "title" ); // Matches the getter method defined as part of the enum.
package com.example.vaadinradiobuttons;
import java.util.ArrayList;
import java.util.List;
/**
*
* @author Basil Bourque
*/
public class Person {
// Members
String name;
Person.VITAL_STATUS vitalStatus;
public enum VITAL_STATUS {
LIVING( "Alive and Kicking" ),
DECEASED( "Dead" ),
UNKNOWN( "DUNNO" );
private String captionText;
static public String CAPTION_TEXT_PROPERTY_NAME = "captionText"; //
VITAL_STATUS ( String t ) {
this.captionText = t;
}
// JavaBeans Property getter.
public String getCaptionText () {
return this.captionText;
}
}
// Constructor
public Person ( String nameArg , VITAL_STATUS vitalStatusArg ) {
this.name = nameArg;
this.vitalStatus = vitalStatusArg;
}
}
package com.example.vaadinradiobuttons;
import javax.servlet.annotation.WebServlet;
import com.vaadin.annotations.Theme;
import com.vaadin.annotations.VaadinServletConfiguration;
import com.vaadin.annotations.Widgetset;
import com.vaadin.data.Property;
import com.vaadin.data.util.BeanItemContainer;
import com.vaadin.server.VaadinRequest;
import com.vaadin.server.VaadinServlet;
import com.vaadin.ui.OptionGroup;
import com.vaadin.ui.UI;
import com.vaadin.ui.VerticalLayout;
import java.util.Arrays;
import java.util.Collection;
/**
*
*/
@Theme ( "mytheme" )
@Widgetset ( "com.example.vaadinradiobuttons.MyAppWidgetset" )
public class MyUI extends UI {
@Override
protected void init ( VaadinRequest vaadinRequest ) {
final VerticalLayout layout = new VerticalLayout();
layout.setMargin( true );
setContent( layout );
// Core of example.
Collection<Person.VITAL_STATUS> v = Arrays.asList( Person.VITAL_STATUS.values() );
BeanItemContainer<Person.VITAL_STATUS> bic = new BeanItemContainer<>( Person.VITAL_STATUS.class , v );
OptionGroup radios = new OptionGroup( "Vital Status :" , bic );
radios.setItemCaptionPropertyId(Person.VITAL_STATUS.CAPTION_TEXT_PROPERTY_NAME ); // …or… ( "captionText" );
radios.setImmediate( true );
radios.addValueChangeListener( ( Property.ValueChangeEvent event ) -> {
Person.VITAL_STATUS vitalStatus = ( Person.VITAL_STATUS ) event.getProperty().getValue();
System.out.println( "User selected a vital status name: " + vitalStatus.name() + ", labeled: " + vitalStatus.toString() );
} );
layout.addComponent( radios );
}
@WebServlet ( urlPatterns = "/*" , name = "MyUIServlet" , asyncSupported = true )
@VaadinServletConfiguration ( ui = MyUI.class , productionMode = false )
public static class MyUIServlet extends VaadinServlet {
}
}
EnumSelect<AddressType> select = new EnumSelect<AddressType>()
.withSelectType(OptionGroup.class);
select.setStyleName(ValoTheme.OPTIONGROUP_HORIZONTAL);
// The Enum type is detected when the edited property is bound to select
// This typically happens via basic bean binding, but here done manually.
ObjectProperty objectProperty = new ObjectProperty(AddressType.Home);
select.setPropertyDataSource(objectProperty);
// Alternatively, if not using databinding at all, you could just use
// basic TypedSelect, or the method from it
// select.setOptions(AddressType.values());