001/*-
002 * #%L
003 * HAPI FHIR - Core Library
004 * %%
005 * Copyright (C) 2014 - 2024 Smile CDR, Inc.
006 * %%
007 * Licensed under the Apache License, Version 2.0 (the "License");
008 * you may not use this file except in compliance with the License.
009 * You may obtain a copy of the License at
010 *
011 *      http://www.apache.org/licenses/LICENSE-2.0
012 *
013 * Unless required by applicable law or agreed to in writing, software
014 * distributed under the License is distributed on an "AS IS" BASIS,
015 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
016 * See the License for the specific language governing permissions and
017 * limitations under the License.
018 * #L%
019 */
020package ca.uhn.fhir.util.adapters;
021
022import jakarta.annotation.Nonnull;
023
024import java.util.HashSet;
025import java.util.Optional;
026import java.util.Set;
027import java.util.stream.Stream;
028
029public class AdapterManager implements IAdapterManager {
030        public static final AdapterManager INSTANCE = new AdapterManager();
031
032        Set<IAdapterFactory> myAdapterFactories = new HashSet<>();
033
034        /**
035         * Hidden to force shared use of the public INSTANCE.
036         */
037        AdapterManager() {}
038
039        public <T> @Nonnull Optional<T> getAdapter(Object theObject, Class<T> theTargetType) {
040                // todo this can be sped up with a cache of type->Factory.
041                return myAdapterFactories.stream()
042                                .filter(nextFactory -> nextFactory.getAdapters().stream().anyMatch(theTargetType::isAssignableFrom))
043                                .flatMap(nextFactory -> {
044                                        var adapter = nextFactory.getAdapter(theObject, theTargetType);
045                                        // can't use Optional.stream() because of our Android target is API level 26/JDK 8.
046                                        if (adapter.isPresent()) {
047                                                return Stream.of(adapter.get());
048                                        } else {
049                                                return Stream.empty();
050                                        }
051                                })
052                                .findFirst();
053        }
054
055        public void registerFactory(@Nonnull IAdapterFactory theFactory) {
056                myAdapterFactories.add(theFactory);
057        }
058
059        public void unregisterFactory(@Nonnull IAdapterFactory theFactory) {
060                myAdapterFactories.remove(theFactory);
061        }
062}