| /* |
| * Copyright (c) OSGi Alliance (2014, 2015). All Rights Reserved. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package org.osgi.util.promise; |
| |
| import org.osgi.annotation.versioning.ConsumerType; |
| |
| /** |
| * Success callback for a Promise. |
| * |
| * <p> |
| * A Success callback is registered with a {@link Promise} using the |
| * {@link Promise#then(Success)} method and is called if the Promise is resolved |
| * successfully. |
| * |
| * <p> |
| * This is a functional interface and can be used as the assignment target for a |
| * lambda expression or method reference. |
| * |
| * @param <T> The value type of the resolved Promise passed as input to this |
| * callback. |
| * @param <R> The value type of the returned Promise from this callback. |
| * |
| * @ThreadSafe |
| * @author $Id$ |
| */ |
| @ConsumerType |
| @FunctionalInterface |
| public interface Success<T, R> { |
| /** |
| * Success callback for a Promise. |
| * |
| * <p> |
| * This method is called if the Promise with which it is registered resolves |
| * successfully. |
| * |
| * <p> |
| * In the remainder of this description we will refer to the Promise |
| * returned by this method as the returned Promise and the Promise returned |
| * by {@link Promise#then(Success)} when this Success callback was |
| * registered as the chained Promise. |
| * |
| * <p> |
| * If the returned Promise is {@code null} then the chained Promise must |
| * resolve immediately with a successful value of {@code null}. If the |
| * returned Promise is not {@code null} then the chained Promise must be |
| * resolved when the returned Promise is resolved. |
| * |
| * @param resolved The successfully resolved {@link Promise}. |
| * @return The Promise to use to resolve the chained Promise, or |
| * {@code null} if the chained Promise is to be resolved immediately |
| * with the value {@code null}. |
| * @throws Exception The chained Promise must be failed with the thrown |
| * exception. |
| */ |
| Promise<R> call(Promise<T> resolved) throws Exception; |
| } |