/*
* Copyright 2015 Petr Bouda
*
* 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.joyrest.examples.combiner.manager;
import java.io.Serializable;
import java.util.Collection;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import org.joyrest.examples.combiner.model.CombinedFeed;
import org.joyrest.examples.combiner.store.DataStoreObserver;
import org.joyrest.examples.combiner.store.InMemoryDataStore;
/**
* This class is used for purposes of processing and listening a new saved or removed entities in {@link InMemoryDataStore} and
* according to
* its {@link CombinedFeed#getRefreshPeriod()} property is able to give an entity into the queue for another processing which
* is dedicated
* to consumers.
*
* @author Petr Bouda
* */
public class FeedDataStoreManager implements DataStoreObserver {
private static final long START_DELAY = 0L;
private final static TimeUnit DEFAULT_TIME_UNIT = TimeUnit.SECONDS;
private final ScheduledExecutorService scheduler;
private final FeedTaskFactory taskFactory;
// Concurrent Map used for purposes of cancellation tasks in the given executor
private Map<String, ScheduledFuture<?>> scheduledTasks = new ConcurrentHashMap<>();
public FeedDataStoreManager(FeedTaskFactory taskFactory) {
this(taskFactory, Executors.newScheduledThreadPool(1));
}
public FeedDataStoreManager(FeedTaskFactory taskFactory, ScheduledExecutorService scheduler) {
this.taskFactory = taskFactory;
this.scheduler = scheduler;
}
@Override
public void save(Serializable entity) {
createTask(entity);
}
@Override
public void saveAll(Collection<Serializable> entities) {
entities.forEach(this::createTask);
}
private void createTask(Serializable serializableEntity) {
if (serializableEntity instanceof CombinedFeed) {
CombinedFeed feed = (CombinedFeed) serializableEntity;
ScheduledFuture<?> scheduledTask = scheduler.scheduleAtFixedRate
(taskFactory.get(feed), START_DELAY, feed.getRefreshPeriod(), DEFAULT_TIME_UNIT);
scheduledTasks.put(feed.getId(), scheduledTask);
}
}
@Override
public void remove(String key) {
removeTask(key);
}
@Override
public void removeAll(Collection<String> keys) {
keys.forEach(this::removeTask);
}
private void removeTask(String key) {
ScheduledFuture<?> scheduledTask = scheduledTasks.get(key);
if (scheduledTask != null) {
scheduledTask.cancel(true);
scheduledTasks.remove(key);
}
}
}