package api;

import java.util.ArrayList;

import java.util.Collection;

import java.util.Iterator;

import java.util.Set;

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

 *

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

 * @version 2.0

 */

public final class Lookups {

    private Lookups() {

    }

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

        return new Lookup() {

            @Override

            <T> Iterator<T> doLookup(Class<T> clazz) {

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

                for (Object obj : instances) {

                    if (clazz.isInstance(obj)) {

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

                    }

                }

                return result.iterator();

            }

        };

    }

    public static Lookup dynamic(final Dynamic provider) {

        return new Lookup() {

            @Override

            <T> Iterator<T> doLookup(Class<T> clazz) {

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

                provider.computeInstances(clazz, result);

                return result.iterator();

            }

        };

    }

    public interface Dynamic {

        public <T> void computeInstances(Class<T> requestedType, Collection<? super T> addInstancesTo);

    }

}