package api;

 import java.util.ArrayList;

 import java.util.Collection;

 import java.util.HashSet;

 import java.util.List;

 import java.util.Set;

 /** Factory to create various types of lookup instances.

  *

  * @author Jaroslav Tulach <jtulach@netbeans.org>

  * @version 1.0

  */

 public final class Lookups {

     private Lookups() {

     }

     public static Lookup fixed(final Object... instances) {

         return new Lookup() {

             @Override

             public <T> T lookup(Class<T> clazz) {

                 for (Object obj : instances) {

                     if (clazz.isInstance(obj)) {

                         return clazz.cast(obj);

                     }

                 }

                 return null;

             }

             @Override

             public <T> Collection<? extends T> lookupAll(Class<T> clazz) {

                 List<T> result = new ArrayList<T>();

                 for (Object obj : instances) {

                     if (clazz.isInstance(obj)) {

                         result.add(clazz.cast(obj));

                     }

                 }

                 return result;

             }

             @Override

             public <T> Set<Class<? extends T>> lookupAllClasses(Class<T> clazz) {

                 Set<Class<? extends T>> result = new HashSet<Class<? extends T>>();

                 for (Object obj : instances) {

                     if (clazz.isInstance(obj)) {

                         result.add(obj.getClass().asSubclass(clazz));

                     }

                 }

                 return result;

             }

         };

     }

 }