/*
* ModeShape (http://www.modeshape.org)
*
* 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.modeshape.jcr;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import java.util.concurrent.CancellationException;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import org.infinispan.Cache;
import org.infinispan.configuration.cache.StoreConfiguration;
import org.infinispan.distexec.DefaultExecutorService;
import org.infinispan.distexec.DistributedCallable;
import org.infinispan.distexec.DistributedExecutorService;
import org.infinispan.tasks.GlobalKeySetTask;
import org.modeshape.common.logging.Logger;
/**
* A set of utility methods for Infinispan caches.
*/
public class InfinispanUtil {
protected static final Logger LOGGER = Logger.getLogger(InfinispanUtil.class);
private InfinispanUtil() {
// prevent instantiation ...
}
public static enum Location {
/** In all processes */
EVERYWHERE,
/** In the local process only, even if the cache is distributed */
LOCALLY;
}
/**
* Utility to run the supplied callable in all the processes where the cache is being run.
*
* @param <K> the type of key used in the cache
* @param <V> the type of value used in the cache
* @param <T> the type of result
* @param cache the cache
* @param location the location where the callable should be run; if null, {@link Location#LOCALLY} is used
* @param callable the callable
* @param combiner the component that can combine multiple results of type <i>T</i> into a single result
* @return the result of the operation
* @throws InterruptedException if the process is interrupted
* @throws ExecutionException if there is an error while getting executing the operation
*/
public static <K, V, T> T execute( Cache<K, V> cache,
Location location,
DistributedCallable<K, V, T> callable,
Combiner<T> combiner ) throws InterruptedException, ExecutionException {
if (location == null) location = Location.LOCALLY;
DistributedExecutorService distributedExecutor = new DefaultExecutorService(cache);
List<StoreConfiguration> stores = cache.getCacheConfiguration().persistence().stores();
boolean shared = (stores != null) && !stores.isEmpty() && stores.get(0).shared();
T result = null;
if (!shared) {
// store is not shared so every node must return key list of the store
List<Future<T>> futures = null;
switch (location) {
case EVERYWHERE:
futures = distributedExecutor.submitEverywhere(callable);
break;
case LOCALLY:
futures = Collections.singletonList(distributedExecutor.submit(callable));
break;
}
while (futures != null && !futures.isEmpty()) {
// Get the next future that is ready ...
Iterator<Future<T>> futureIter = futures.iterator();
while (futureIter.hasNext()) {
Future<T> future = futureIter.next();
try {
// But done't wait too long for this future ...
T value = future.get(100, TimeUnit.MILLISECONDS);
// We got some keys, so this future is done and should be removed from our list ...
futureIter.remove();
result = combiner.combine(result, value);
} catch (TimeoutException e) {
// continue;
}
}
if (futures.isEmpty()) break;
}
} else {
// store is shared, so we can short-circuit the logic and just run locally; otherwise, if distributed
// each process will see the all of the keys ...
result = distributedExecutor.submit(callable).get();
}
return result;
}
/**
* The interface that defines how the results should be merged
*
* @param <T>
*/
public static interface Combiner<T> {
T combine( T priorResult,
T newResult ) throws InterruptedException, ExecutionException;
}
/**
* Get all of the keys in the cache.
*
* @param <K> the type of key
* @param <V> the type of value
* @param cache the cache
* @return the sequence that can be used to obtain the keys; never null
* @throws InterruptedException if the process is interrupted
* @throws ExecutionException if there is an error while getting all keys
*/
public static <K, V> Sequence<K> getAllKeys( Cache<K, V> cache )
throws InterruptedException, ExecutionException {
LOGGER.debug("getAllKeys of {0}", cache.getName());
Set<K> cacheKeys = GlobalKeySetTask.getGlobalKeySet(cache);
return new IteratorSequence<K>(cacheKeys.iterator());
}
/**
* A sequence of values. This abstracts how the values are obtained.
*
* @param <T> the key type
*/
public static interface Sequence<T> {
/**
* Get the next values.
*
* @return the next value, or null if there are no more values.
* @throws ExecutionException if there is an exception obtaining the next value
* @throws CancellationException if the operation finding the values has been cancelled
* @throws InterruptedException if the operation finding the values has been interrupted
*/
T next() throws ExecutionException, CancellationException, InterruptedException;
boolean hasNext();
}
private static final class IteratorSequence<T> implements Sequence<T> {
private final Iterator<T> iterator;
public IteratorSequence( Iterator<T> iterator ) {
this.iterator = iterator;
}
@Override
public T next() {
return iterator.hasNext() ? iterator.next() : null;
}
@Override
public boolean hasNext() {
return iterator.hasNext();
}
}
}