| /* |
| * Copyright (c) OSGi Alliance (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.pushstream; |
| |
| import org.osgi.annotation.versioning.ConsumerType; |
| |
| /** |
| * An Async Event Consumer asynchronously receives Data events until it receives |
| * either a Close or Error event. |
| * |
| * @param <T> |
| * The type for the event payload |
| */ |
| @ConsumerType |
| @FunctionalInterface |
| public interface PushEventConsumer<T> { |
| |
| /** |
| * If ABORT is used as return value, the sender should close the channel all |
| * the way to the upstream source. The ABORT will not guarantee that no |
| * more events are delivered since this is impossible in a concurrent |
| * environment. The consumer should accept subsequent events and close/clean |
| * up when the Close or Error event is received. |
| * |
| * Though ABORT has the value -1, any value less than 0 will act as an |
| * abort. |
| */ |
| long ABORT = -1; |
| |
| /** |
| * A 0 indicates that the consumer is willing to receive subsequent events |
| * at full speeds. |
| * |
| * Any value more than 0 will indicate that the consumer is becoming |
| * overloaded and wants a delay of the given milliseconds before the next |
| * event is sent. This allows the consumer to pushback the event delivery |
| * speed. |
| */ |
| long CONTINUE = 0; |
| |
| /** |
| * Accept an event from a source. Events can be delivered on multiple |
| * threads simultaneously. However, Close and Error events are the last |
| * events received, no more events must be sent after them. |
| * |
| * @param event The event |
| * @return less than 0 means abort, 0 means continue, more than 0 means |
| * delay ms |
| * @throws Exception to indicate that an error has occured and that no |
| * further events should be delivered to this |
| * {@link PushEventConsumer} |
| */ |
| long accept(PushEvent<? extends T> event) throws Exception; |
| |
| } |