DZone
Java Zone
Thanks for visiting DZone today,
Edit Profile
  • Manage Email Subscriptions
  • How to Post to DZone
  • Article Submission Guidelines
Sign Out View Profile
  • Post an Article
  • Manage My Drafts
Over 2 million developers have joined DZone.
Log In / Join
  • Refcardz
  • Trend Reports
  • Webinars
  • Zones
  • |
    • Agile
    • AI
    • Big Data
    • Cloud
    • Database
    • DevOps
    • Integration
    • IoT
    • Java
    • Microservices
    • Open Source
    • Performance
    • Security
    • Web Dev
DZone > Java Zone > Working with multiple CDI qualifiers

Working with multiple CDI qualifiers

A. Programmer user avatar by
A. Programmer
·
Apr. 23, 11 · Java Zone · Interview
Like (0)
Save
Tweet
7.62K Views

Join the DZone community and get the full member experience.

Join For Free

An injection point may specify multiple qualifiers. When you specify multiple qualifiers, only the beans that annotated with those qualifiers will be injected - a bean can have multiple qualifiers and injection points only need to specify enough qualifiers to uniquely match a bean. Per example, let us suppose that you have the below two qualifiers – each qualifier represent a tennis player:

package com.racquets;

//imports here

@Qualifier
@Retention(RUNTIME)
@Target({METHOD, FIELD, PARAMETER, TYPE})
public @interface JoWilfriedTsonga {
}

package com.racquets;

//imports here

@Qualifier
@Retention(RUNTIME)
@Target({METHOD, FIELD, PARAMETER, TYPE})
public @interface RafaelNadal {
}

Both top players, Rafael Nadal and Jo-Wilfred Tonga play with the same racquet, a Babolat AeroPro Drive GT. Therefore, a possible implementation of RacquetType type can be annotated with both qualifiers from above:
package com.racquets;

@RafaelNadal @JoWilfriedTsonga
public class AeroProDriveGTRacquet implements RacquetType {

@Override
public String getRacquetType() {
return ("Babolat AeroPro Drive GT");
}
}


Now, at the injection point you must specify both qualifiers, like below:
package com.racquets;

import javax.enterprise.context.RequestScoped;
import javax.inject.Inject;
import javax.inject.Named;

@RequestScoped
@Named
public class AeroProDriveGTBean {

@Inject @RafaelNadal @JoWilfriedTsonga RacquetType aeroprodrivegtRacquet;
private String aeroprodrivegtRacquetName;

public String getAeroprodrivegtRacquetName() {
aeroprodrivegtRacquetName = aeroprodrivegtRacquet.getRacquetType();
return aeroprodrivegtRacquetName;
}
}


From a JSF page, you can test multiple qualifiers like this:
<br/><h3><b>Multiple qualifiers</b></h3>        
<b>Rafael Nadal and Jo-Wilfried Tsonga racquet:</b>
<h:outputText value="#{aeroProDriveGTBean.aeroprodrivegtRacquetName}" /><br/>


The output is in figure below:

 

From http://e-blog-java.blogspot.com/2011/04/working-with-multiple-cdi-qualifiers.html

CDI

Opinions expressed by DZone contributors are their own.

Popular on DZone

  • Ultra-Fast Microservices: When Microstream Meets Wildfly
  • Role of Development Team in an Agile Environment
  • Applying Kappa Architecture to Make Data Available Where It Matters
  • Maven Tutorial: Nice and Easy [Video]

Comments

Java Partner Resources

X

ABOUT US

  • About DZone
  • Send feedback
  • Careers
  • Sitemap

ADVERTISE

  • Advertise with DZone

CONTRIBUTE ON DZONE

  • Article Submission Guidelines
  • MVB Program
  • Become a Contributor
  • Visit the Writers' Zone

LEGAL

  • Terms of Service
  • Privacy Policy

CONTACT US

  • 600 Park Offices Drive
  • Suite 300
  • Durham, NC 27709
  • support@dzone.com
  • +1 (919) 678-0300

Let's be friends:

DZone.com is powered by 

AnswerHub logo