ClientId.java

package org.jboss.seam.faces.component;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import javax.enterprise.util.Nonbinding;
import javax.inject.Qualifier;

/**
 * @author Dan Allen
 */
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD, ElementType.FIELD, ElementType.PARAMETER})
@Qualifier
public @interface ClientId {
   /**
    * The search expression that matches one or more UIComponent instances by its clientId.
    */
   @Nonbinding String value() default "";
}

ExampleController.java

public class ExampleController
{
   @Inject @ClientId("registerButton") UICommand registerButton;

   public void action()
   {
      System.out.println(registerButton);
   }
}

UIComponentProducer.java

package org.jboss.seam.faces.component;

import java.lang.annotation.Annotation;
import java.util.Set;
import javax.enterprise.inject.Produces;
import javax.enterprise.inject.Typed;
import javax.enterprise.inject.spi.InjectionPoint;
import javax.faces.component.EditableValueHolder;
import javax.faces.component.UICommand;
import javax.faces.component.UIComponent;
import javax.faces.component.UIData;
import javax.faces.component.UIForm;
import javax.faces.component.UIInput;
import javax.faces.component.UIPanel;
import javax.faces.context.FacesContext;

/**
 * @author Dan Allen
 */
public class UIComponentProducer
{
   public @Produces @ClientId UIComponent findComponent(InjectionPoint ip, FacesContext ctx)
   {
      return findComponentWithType(ip, ctx, UIComponent.class);
   }

   public @Produces @ClientId @Typed(UIForm.class) UIForm findFormComponent(InjectionPoint ip, FacesContext ctx)
   {
      return findComponentWithType(ip, ctx, UIForm.class);
   }

   public @Produces @ClientId @Typed(UICommand.class) UICommand findCommandComponent(InjectionPoint ip, FacesContext ctx)
   {
      return findComponentWithType(ip, ctx, UICommand.class);
   }

   public @Produces @ClientId @Typed(UIInput.class) UIInput findInputComponent(InjectionPoint ip, FacesContext ctx)
   {
      return findComponentWithType(ip, ctx, UIInput.class);
   }

   public @Produces @ClientId @Typed(UIPanel.class) UIPanel findPanelComponent(InjectionPoint ip, FacesContext ctx)
   {
      return findComponentWithType(ip, ctx, UIPanel.class);
   }

   public @Produces @ClientId @Typed(UIData.class) UIData findDataComponent(InjectionPoint ip, FacesContext ctx)
   {
      return findComponentWithType(ip, ctx, UIData.class);
   }

   private <T extends UIComponent> T findComponentWithType(InjectionPoint ip, FacesContext ctx, Class<T> expectedType)
   {
      UIComponent candidate = ctx.getViewRoot().findComponent(getSearchExpression(ip));
      if (candidate != null && expectedType.isAssignableFrom(candidate.getClass()))
      {
         return expectedType.cast(candidate);
      }
      return null;
   }

   private String getSearchExpression(InjectionPoint ip)
   {
      for (Annotation candidate : ip.getQualifiers())
      {
         if (candidate.annotationType().equals(ClientId.class))
         {
            String expr = ((ClientId) candidate).value().trim();
            if (expr.length() == 0)
            {
               throw new IllegalArgumentException("Client id value cannot be empty at " + ip);
            }
            return expr;
         }
      }
      throw new IllegalArgumentException("Injection point " + ip + " does not have " + ClientId.class + " qualifier");
   }
}