/*
* Copyright (c) 2008-2013, Hazelcast, Inc. 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 com.hazelcast.client.nearcache;
import com.hazelcast.client.BaseClientRemoveListenerRequest;
import com.hazelcast.client.ClientRequest;
import com.hazelcast.client.spi.ClientContext;
import com.hazelcast.client.spi.EventHandler;
import com.hazelcast.client.util.ListenerUtil;
import com.hazelcast.config.InMemoryFormat;
import com.hazelcast.config.NearCacheConfig;
import com.hazelcast.logging.Logger;
import com.hazelcast.map.client.MapAddEntryListenerRequest;
import com.hazelcast.map.client.MapRemoveEntryListenerRequest;
import com.hazelcast.monitor.impl.NearCacheStatsImpl;
import com.hazelcast.nio.serialization.Data;
import com.hazelcast.spi.impl.PortableEntryEvent;
import com.hazelcast.util.Clock;
import com.hazelcast.util.ExceptionUtil;
import java.util.Comparator;
import java.util.Map;
import java.util.TreeSet;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.RejectedExecutionException;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;
/**
* @ali 7/18/13
*/
public class ClientNearCache<K> {
public static final int EVICTION_PERCENTAGE = 20;
public static final int TTL_CLEANUP_INTERVAL_MILLS = 5000;
final ClientNearCacheType cacheType;
final int maxSize;
volatile long lastCleanup;
final long maxIdleMillis;
final long timeToLiveMillis;
final boolean invalidateOnChange;
final EvictionPolicy evictionPolicy;
final InMemoryFormat inMemoryFormat;
final String mapName;
final ClientContext context;
final AtomicBoolean canCleanUp;
final AtomicBoolean canEvict;
final ConcurrentMap<K, CacheRecord<K>> cache;
public static final Object NULL_OBJECT = new Object();
String registrationId = null;
final NearCacheStatsImpl clientNearCacheStats;
private final Comparator<CacheRecord<K>> comparator = new Comparator<CacheRecord<K>>() {
public int compare(CacheRecord<K> o1, CacheRecord<K> o2) {
if (EvictionPolicy.LRU.equals(evictionPolicy))
return ((Long) o1.lastAccessTime).compareTo((o2.lastAccessTime));
else if (EvictionPolicy.LFU.equals(evictionPolicy))
return ((Integer) o1.hit.get()).compareTo((o2.hit.get()));
return 0;
}
};
public ClientNearCache(String mapName, ClientNearCacheType cacheType, ClientContext context, NearCacheConfig nearCacheConfig) {
this.mapName = mapName;
this.cacheType = cacheType;
this.context = context;
maxSize = nearCacheConfig.getMaxSize();
maxIdleMillis = nearCacheConfig.getMaxIdleSeconds() * 1000;
inMemoryFormat = nearCacheConfig.getInMemoryFormat();
timeToLiveMillis = nearCacheConfig.getTimeToLiveSeconds() * 1000;
invalidateOnChange = nearCacheConfig.isInvalidateOnChange();
evictionPolicy = EvictionPolicy.valueOf(nearCacheConfig.getEvictionPolicy());
cache = new ConcurrentHashMap<K, CacheRecord<K>>();
canCleanUp = new AtomicBoolean(true);
canEvict = new AtomicBoolean(true);
lastCleanup = Clock.currentTimeMillis();
clientNearCacheStats = new NearCacheStatsImpl();
if (invalidateOnChange) {
addInvalidateListener();
}
}
private void addInvalidateListener() {
try {
ClientRequest request;
EventHandler handler;
if (cacheType == ClientNearCacheType.Map) {
request = new MapAddEntryListenerRequest(mapName, false);
handler = new EventHandler<PortableEntryEvent>() {
public void handle(PortableEntryEvent event) {
cache.remove(event.getKey());
}
@Override
public void onListenerRegister() {
cache.clear();
}
};
} else {
throw new IllegalStateException("Near cache is not available for this type of data structure");
}
registrationId = ListenerUtil.listen(context, request, null, handler); //TODO callback
} catch (Exception e) {
Logger.getLogger(ClientNearCache.class).severe("-----------------\n Near Cache is not initialized!!! \n-----------------", e);
}
}
static enum EvictionPolicy {
NONE, LRU, LFU
}
public void put(K key, Object object) {
fireTtlCleanup();
if (evictionPolicy == EvictionPolicy.NONE && cache.size() >= maxSize) {
return;
}
if (evictionPolicy != EvictionPolicy.NONE && cache.size() >= maxSize) {
fireEvictCache();
}
Object value;
if (object == null) {
value = NULL_OBJECT;
} else {
value = inMemoryFormat.equals(InMemoryFormat.BINARY) ? context.getSerializationService().toData(object) : object;
}
cache.put(key, new CacheRecord<K>(key, value));
}
private void fireEvictCache() {
if (canEvict.compareAndSet(true, false)) {
try {
context.getExecutionService().execute(new Runnable() {
public void run() {
try {
TreeSet<CacheRecord<K>> records = new TreeSet<CacheRecord<K>>(comparator);
records.addAll(cache.values());
int evictSize = cache.size() * EVICTION_PERCENTAGE / 100;
int i = 0;
for (CacheRecord<K> record : records) {
cache.remove(record.key);
if (++i > evictSize)
break;
}
} finally {
canEvict.set(true);
}
}
});
} catch (RejectedExecutionException e) {
canEvict.set(true);
} catch (Exception e) {
throw ExceptionUtil.rethrow(e);
}
}
}
private void fireTtlCleanup() {
if (Clock.currentTimeMillis() < (lastCleanup + TTL_CLEANUP_INTERVAL_MILLS))
return;
if (canCleanUp.compareAndSet(true, false)) {
try {
context.getExecutionService().execute(new Runnable() {
public void run() {
try {
lastCleanup = Clock.currentTimeMillis();
for (Map.Entry<K, CacheRecord<K>> entry : cache.entrySet()) {
if (entry.getValue().expired()) {
cache.remove(entry.getKey());
}
}
} finally {
canCleanUp.set(true);
}
}
});
} catch (RejectedExecutionException e) {
canCleanUp.set(true);
} catch (Exception e) {
throw ExceptionUtil.rethrow(e);
}
}
}
public void invalidate(K key) {
cache.remove(key);
}
public Object get(K key) {
fireTtlCleanup();
CacheRecord<K> record = cache.get(key);
if (record != null) {
if (record.expired()) {
cache.remove(key);
clientNearCacheStats.incrementMisses();
return null;
}
if (record.value.equals(NULL_OBJECT)) {
clientNearCacheStats.incrementMisses();
return NULL_OBJECT;
}
record.access();
return inMemoryFormat.equals(InMemoryFormat.BINARY) ? context.getSerializationService().toObject((Data) record.value) : record.value;
} else {
clientNearCacheStats.incrementMisses();
return null;
}
}
public NearCacheStatsImpl getNearCacheStats() {
return createNearCacheStats();
}
private NearCacheStatsImpl createNearCacheStats() {
long ownedEntryCount = cache.values().size();
long ownedEntryMemory = 0;
for (CacheRecord record : cache.values()) {
ownedEntryMemory += record.getCost();
}
clientNearCacheStats.setOwnedEntryCount(ownedEntryCount);
clientNearCacheStats.setOwnedEntryMemoryCost(ownedEntryMemory);
return clientNearCacheStats;
}
public void destroy() {
if (registrationId != null) {
BaseClientRemoveListenerRequest request;
if (cacheType == ClientNearCacheType.Map) {
request = new MapRemoveEntryListenerRequest(mapName, registrationId);
} else {
throw new IllegalStateException("Near cache is not available for this type of data structure");
}
ListenerUtil.stopListening(context, request, registrationId);
}
cache.clear();
}
class CacheRecord<K> {
final K key;
final Object value;
volatile long lastAccessTime;
final long creationTime;
final AtomicInteger hit;
CacheRecord(K key, Object value) {
this.key = key;
this.value = value;
long time = Clock.currentTimeMillis();
this.lastAccessTime = time;
this.creationTime = time;
this.hit = new AtomicInteger(0);
}
void access() {
hit.incrementAndGet();
clientNearCacheStats.incrementHits();
lastAccessTime = Clock.currentTimeMillis();
}
public long getCost() {
// todo find object size if not a Data instance.
if (!(value instanceof Data)) return 0;
if (!(key instanceof Data)) return 0;
// value is Data
return ((Data) key).getHeapCost()
+ ((Data) value).getHeapCost()
+ 2 * (Long.SIZE / Byte.SIZE)
// sizeof atomic integer
+ (Integer.SIZE / Byte.SIZE)
// object references (key, value, hit)
+ 3 * (Integer.SIZE / Byte.SIZE);
}
boolean expired() {
long time = Clock.currentTimeMillis();
return (maxIdleMillis > 0 && time > lastAccessTime + maxIdleMillis) || (timeToLiveMillis > 0 && time > creationTime + timeToLiveMillis);
}
}
}