| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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.apache.rya.streams.querymanager; |
| |
| import org.apache.rya.streams.api.queries.QueryChangeLog; |
| |
| import com.google.common.util.concurrent.Service; |
| |
| import edu.umd.cs.findbugs.annotations.DefaultAnnotation; |
| import edu.umd.cs.findbugs.annotations.NonNull; |
| |
| /** |
| * A {@link QueryChangeLog} source represents a storage where the change logs reside, but it |
| * does not provide a way to create or remove them. Instead, subscribed {@link SourceListener}s |
| * are notified whenever a change log is created or removed from the storage. |
| */ |
| @DefaultAnnotation(NonNull.class) |
| public interface QueryChangeLogSource extends Service { |
| |
| /** |
| * Adds a {@link SourceListener} to be notified when {@link QueryChangeLog}s |
| * have been found. |
| * <p> |
| * When a new subscriber is added, it will be notified with the existing {@link QueryChangeLog}s. |
| * |
| * @param listener - The {@link SourceListener} to add. (not null) |
| */ |
| public void subscribe(final SourceListener listener); |
| |
| /** |
| * Removes a {@link SourceListener}. |
| * |
| * @param listener - The {@link SourceListener} to remove. (not null) |
| */ |
| public void unsubscribe(final SourceListener listener); |
| |
| /** |
| * A listener that is notified when a {@link QueryChangeLog} has been added or |
| * removed from a {@link QueryChangeLogSource}. The listener receives the only |
| * copy of the change log and is responsible for shutting it down. |
| */ |
| @DefaultAnnotation(NonNull.class) |
| public interface SourceListener { |
| /** |
| * Notifies the subscriber that there is a new {@link QueryChangeLog} in the |
| * {@link QueryChangeLogSource}. |
| * |
| * @param ryaInstanceName - The Rya Instance name the {@link QueryChangeLog} belongs to. (not null) |
| * @param log - The new {@link QueryChangeLog}. (not null) |
| */ |
| public void notifyCreate(final String ryaInstanceName, final QueryChangeLog log); |
| |
| /** |
| * Notifies the subscriber that a {@link QueryChangeLog} has been deleted |
| * from the {@link QueryChangeLogSource}. |
| * |
| * @param ryaInstanceName - The rya instance whose {@link QueryChangeLog} was removed. (not null) |
| */ |
| public void notifyDelete(final String ryaInstanceName); |
| } |
| } |