跳至主要内容

JSF 2.3 : Injection supports in Converter, Validator and Behavior

Injection supports in Converter, Validator and Behavior

In JSF 2.3, Converter, Validator and Behavior are refactored to generic interfaces.
Have a look at the Converter interface.
public interface Converter<T> {

    public T getAsObject(FacesContext context, UIComponent component,
                              String value);

    public String getAsString(FacesContext context, UIComponent component,
                              T value);  
}
And these interfaces also support @Inject and also can be injected into other beans, which are originally planned in JSF 2.2, but delayed to be implemented in JSF 2.3.
Let's create a simple sample to taste it. TagsConverter is used to convert tag string to a tag list in backing bean.
@FacesConverter(value = "tagsConverter", managed = true)
public class TagsConverter implements Converter<List<String>> {
    
    @Inject
    ConverterUtils utils;

    @Override
    public List<String> getAsObject(FacesContext context, UIComponent component, String value) {
       return utils.stringToList(value);
    }

    @Override
    public String getAsString(FacesContext context, UIComponent component, List<String> value) {
       return utils.listToString(value);
    }

}
managed = true indicates the converter is a CDI managed converter.
To demonstrate @Inject supports in Converter, I extracted the conversion handling process into a CDI bean ConverterUtils, and inject it in TagsConverter.
@ApplicationScoped
public class ConverterUtils {

    @Inject
    Logger LOG;

    public String listToString(List<String> value) {
        LOG.log(Level.INFO, "listToString:{0}", value);
        return value != null ? join(",", value) : "";
    }

    public List<String> stringToList(String value) {
        LOG.log(Level.INFO, "stringToList:{0}", value);
        return value != null ? Arrays.asList(value.split(",")) : Collections.<String>emptyList();
    }

}
Now you can apply this converter on an input field in a facelets template.
 <div>
 <h:outputLabel for="tags" value="Tags" />
 <h:inputText 
  id="tags" 
  value="#{backingBean.tags}">
  <f:converter converterId="tagsConverter" />
 </h:inputText>    
</div>
The backingBean code is:
@RequestScoped
@Named
public class BackingBean {


    List<String> tags = new ArrayList<>();


    public List<String> getTags() {
        return tags;
    }

    public void setTags(List<String> tags) {
        this.tags = tags;
    }

   

}
And the TagsConverter can be injected into other beans like other generic CDI beans.
@RequestScoped
@Named
public class BackingBean {

    @Inject
    @FacesConverter(value="tagsConverter", managed = true)
    TagsConverter mytagsConverter;
 
 List<String> mytags = new ArrayList<>();
 
 public List<String> getMytags() {
        return mytags;
    }

    public void setMytags(List<String> mytags) {
        this.mytags = mytags;
    }

//...

}
In the facelets template, we can bind it to the converter directly.
<div>
 <h:outputLabel for="mytags" value="My Tags" />
 <h:inputText 
  id="mytags" 
  value="#{backingBean.mytags}">
  <f:converter binding="#{backingBean.mytagsConverter}"/>
 </h:inputText>     
</div>
Let's run this sample on Glassfish v5, open browser and navigate to http://localhost:8080/jsf-converter/converter.faces.
jsf converter
Grab the source codes from my github account, and have a try.
发表评论

此博客中的热门博文

JPA 2.1: Attribute Converter

JPA 2.1: Attribute Converter If you are using Hibernate, and want a customized type is supported in your Entity class, you could have to write a custom Hibernate Type. JPA 2.1 brings a new feature named attribute converter, which can help you convert your custom class type to JPA supported type. Create an Entity Reuse thePostentity class as example. @Entity @Table(name="POSTS") public class Post implements Serializable { private static final long serialVersionUID = 1L; @Id @GeneratedValue(strategy = GenerationType.AUTO) @Column(name="ID") private Long id; @Column(name="TITLE") private String title; @Column(name="BODY") private String body; @Temporal(javax.persistence.TemporalType.DATE) @Column(name="CREATED") private Date created; @Column(name="TAGS") private List<String> tags=new ArrayList<>(); } Create an attribute converter In this example…

Auditing with Hibernate Envers

Auditing with Hibernate Envers The approaches provided in JPA lifecyle hook and Spring Data auditing only track the creation and last modification info of an Entity, but all the modification history are not tracked. Hibernate Envers fills the blank table. Since Hibernate 3.5, Envers is part of Hibernate core project. Configuration Configure Hibernate Envers in your project is very simple, just need to addhibernate-enversas project dependency. <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-envers</artifactId> </dependency> Done. No need extra Event listeners configuration as the early version. Basic Usage Hibernate Envers provides a simple@Auditedannotation, you can place it on an Entity class or property of an Entity. @Audited private String description; If@Auditedannotation is placed on a property, this property can be tracked.

Spring Data Mongo: bridge MongoDB and Spring

Spring Data Mongo: bridge MongoDB and SpringMongoDBis one of the most popular NoSQL products, Spring Data Mongo(Maven archetype id is spring-data-mongodb) tries to provides a simple approach to access MongoDB. Configuration Add the following code fragments in your Spring configuration. <!-- Mongo config --> <mongo:db-factory id="mongoDbFactory" host="localhost" port="27017" dbname="conference-db" /> <bean id="mongoTemplate" class="org.springframework.data.mongodb.core.MongoTemplate"> <constructor-arg ref="mongoDbFactory" /> </bean> <mongo:repositories base-package="com.hantsylabs.example.spring.mongo" /> Firstly, declare aDbFactorywhich is responsible for connecting to the MongoDB server. Then, register theMongoTemplateobject which envelop the data operations on MongoDB. Lastly addmongo:repositorieswith an essentialbase-packageattribute, Spring will discovery your d…