net.sf.ehcache.store.cachingtier.OnHeapCachingTier Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of ehcache Show documentation
Show all versions of ehcache Show documentation
Ehcache is an open source, standards-based cache used to boost performance,
offload the database and simplify scalability. Ehcache is robust, proven and full-featured and
this has made it the most widely-used Java-based cache.
/**
* Copyright Terracotta, Inc.
*
* 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 net.sf.ehcache.store.cachingtier;
import net.sf.ehcache.CacheException;
import net.sf.ehcache.Ehcache;
import net.sf.ehcache.Element;
import net.sf.ehcache.config.AbstractCacheConfigurationListener;
import net.sf.ehcache.config.PinningConfiguration;
import net.sf.ehcache.config.SizeOfPolicyConfiguration;
import net.sf.ehcache.pool.Pool;
import net.sf.ehcache.pool.Size;
import net.sf.ehcache.pool.SizeOfEngine;
import net.sf.ehcache.pool.SizeOfEngineLoader;
import net.sf.ehcache.pool.sizeof.annotations.IgnoreSizeOf;
import net.sf.ehcache.store.CachingTier;
import net.sf.ehcache.store.FifoPolicy;
import net.sf.ehcache.store.LfuPolicy;
import net.sf.ehcache.store.LruPolicy;
import net.sf.ehcache.store.MemoryStoreEvictionPolicy;
import net.sf.ehcache.store.Policy;
import java.util.List;
import java.util.Map;
import java.util.concurrent.Callable;
import java.util.concurrent.CopyOnWriteArrayList;
import net.sf.ehcache.store.StoreOperationOutcomes.GetOutcome;
import net.sf.ehcache.store.StoreOperationOutcomes.PutOutcome;
import net.sf.ehcache.store.StoreOperationOutcomes.RemoveOutcome;
import org.terracotta.context.annotations.ContextChild;
import org.terracotta.statistics.Statistic;
import org.terracotta.statistics.observer.OperationObserver;
import static net.sf.ehcache.statistics.StatisticBuilder.operation;
/**
* An instance of this class will delegate the storage to the backing HeapCacheBackEnd.
* Adding :
*
* - making sure only a single thread populates the cache for a given key at a time
* - translate calls to the eviction listeners
* - Add all the crap about sizing and stuff
*
*
* @param The key type
* @param the value type
* @author Alex Snaps
*/
public class OnHeapCachingTier implements CachingTier {
@ContextChild
private final HeapCacheBackEnd backEnd;
private final OperationObserver getObserver = operation(GetOutcome.class).named("get").of(this).tag("local-heap").build();
private final OperationObserver putObserver = operation(PutOutcome.class).named("put").of(this).tag("local-heap").build();
private final OperationObserver removeObserver = operation(RemoveOutcome.class).named("remove").of(this).tag("local-heap").build();
private volatile List> listeners = new CopyOnWriteArrayList>();
/**
* A Constructor
*
* @param backEnd the HeapCacheBackEnd that will back this CachingTier
*/
public OnHeapCachingTier(final HeapCacheBackEnd backEnd) {
this.backEnd = backEnd;
this.backEnd.registerEvictionCallback(new HeapCacheBackEnd.EvictionCallback() {
@Override
public void evicted(final K key, final Object value) {
final V v = getValue(value);
if (v != null) {
for (Listener listener : listeners) {
listener.evicted(key, v);
}
}
}
});
}
/**
* Factory method
* @param cache the cache we're planning to back
* @param onHeapPool the pool, if any, to use
* @return the OnHeapCachingTier properly configured for this cache
*/
public static OnHeapCachingTier createOnHeapCache(final Ehcache cache, final Pool onHeapPool) {
final HeapCacheBackEnd memCacheBackEnd;
final Policy memoryEvictionPolicy = determineEvictionPolicy(cache);
if (cache.getCacheConfiguration().isCountBasedTuned()) {
final long maxEntriesLocalHeap = getCachingTierMaxEntryCount(cache);
final CountBasedBackEnd countBasedBackEnd =
new CountBasedBackEnd(maxEntriesLocalHeap, memoryEvictionPolicy);
memCacheBackEnd = countBasedBackEnd;
cache.getCacheConfiguration().addConfigurationListener(new AbstractCacheConfigurationListener() {
@Override
public void memoryCapacityChanged(final int oldCapacity, final int newCapacity) {
countBasedBackEnd.setMaxEntriesLocalHeap(newCapacity);
}
});
} else {
final PooledBasedBackEnd pooledBasedBackEnd = new PooledBasedBackEnd(memoryEvictionPolicy);
pooledBasedBackEnd.registerAccessor(
onHeapPool.createPoolAccessor(new PooledBasedBackEnd.PoolParticipant(pooledBasedBackEnd),
SizeOfPolicyConfiguration.resolveMaxDepth(cache),
SizeOfPolicyConfiguration.resolveBehavior(cache)
.equals(SizeOfPolicyConfiguration.MaxDepthExceededBehavior.ABORT)));
memCacheBackEnd = pooledBasedBackEnd;
}
return new OnHeapCachingTier(
memCacheBackEnd);
}
/**
* Chooses the Policy from the cache configuration
*
* @param cache the cache
* @return the chosen eviction policy
*/
static Policy determineEvictionPolicy(Ehcache cache) {
MemoryStoreEvictionPolicy policySelection = cache.getCacheConfiguration().getMemoryStoreEvictionPolicy();
if (policySelection.equals(MemoryStoreEvictionPolicy.LRU)) {
return new LruPolicy();
} else if (policySelection.equals(MemoryStoreEvictionPolicy.FIFO)) {
return new FifoPolicy();
} else if (policySelection.equals(MemoryStoreEvictionPolicy.LFU)) {
return new LfuPolicy();
} else if (policySelection.equals(MemoryStoreEvictionPolicy.CLOCK)) {
return new LruPolicy();
}
throw new IllegalArgumentException(policySelection + " isn't a valid eviction policy");
}
private static long getCachingTierMaxEntryCount(final Ehcache cache) {
final PinningConfiguration pinningConfiguration = cache.getCacheConfiguration().getPinningConfiguration();
if (pinningConfiguration != null && pinningConfiguration.getStore() != PinningConfiguration.Store.INCACHE) {
return 0;
}
return cache.getCacheConfiguration().getMaxEntriesLocalHeap();
}
@Override
public boolean loadOnPut() {
return backEnd.hasSpace();
}
@Override
public V get(final K key, final Callable source, final boolean updateStats) {
if (updateStats) { getObserver.begin(); }
Object cachedValue = backEnd.get(key);
if (cachedValue == null) {
if (updateStats) { getObserver.end(GetOutcome.MISS); }
Fault f = new Fault(source);
cachedValue = backEnd.putIfAbsent(key, f);
if (cachedValue == null) {
try {
V value = f.get();
putObserver.begin();
if (value == null) {
backEnd.remove(key, f);
} else if (backEnd.replace(key, f, value)) {
putObserver.end(PutOutcome.ADDED);
} else {
V p = getValue(backEnd.remove(key));
return p == null ? value : p;
}
return value;
} catch (Throwable e) {
backEnd.remove(key, f);
if (e instanceof RuntimeException) {
throw (RuntimeException)e;
} else {
throw new CacheException(e);
}
}
}
} else {
if (updateStats) { getObserver.end(GetOutcome.HIT); }
}
return getValue(cachedValue);
}
@Override
public V remove(final K key) {
removeObserver.begin();
try {
return getValue(backEnd.remove(key));
} finally {
removeObserver.end(RemoveOutcome.SUCCESS);
}
}
@Override
public void clear() {
backEnd.clear(false);
}
@Override
public void clearAndNotify() {
backEnd.clear(true);
}
@Override
public void addListener(final Listener listener) {
if (listener == null) {
throw new NullPointerException("Listener can't be null!");
}
listeners.add(listener);
}
@Statistic(name = "size", tags = "local-heap")
@Override
public int getInMemorySize() {
return backEnd.size();
}
@Override
public int getOffHeapSize() {
return 0;
}
@Override
public boolean contains(final K key) {
return backEnd.get(key) != null;
}
@Statistic(name = "size-in-bytes", tags = "local-heap")
@Override
public long getInMemorySizeInBytes() {
long sizeInBytes;
if (backEnd instanceof PooledBasedBackEnd) {
sizeInBytes = ((PooledBasedBackEnd)backEnd).getSizeInBytes();
} else {
SizeOfEngine defaultSizeOfEngine = SizeOfEngineLoader.newSizeOfEngine(
SizeOfPolicyConfiguration.DEFAULT_MAX_SIZEOF_DEPTH,
SizeOfPolicyConfiguration.DEFAULT_MAX_DEPTH_EXCEEDED_BEHAVIOR == SizeOfPolicyConfiguration.MaxDepthExceededBehavior.ABORT,
true
);
sizeInBytes = 0;
for (Map.Entry entry : backEnd.entrySet()) {
// This could leak Fault values... We ignore these entirely
if (entry.getValue() != null && entry.getValue() instanceof Element) {
Element element = (Element)entry.getValue();
// TODO this is a lie here! Should we add a dedicated method to BackEnd to return a container ?
Size size = defaultSizeOfEngine.sizeOf(element.getObjectKey(), element, null);
sizeInBytes += size.getCalculated();
}
}
}
return sizeInBytes;
}
@Override
public long getOffHeapSizeInBytes() {
return 0;
}
@Override
public long getOnDiskSizeInBytes() {
return 0;
}
@Override
public void recalculateSize(final K key) {
backEnd.recalculateSize(key);
}
@Override
public Policy getEvictionPolicy() {
return backEnd.getPolicy();
}
@Override
public void setEvictionPolicy(final Policy policy) {
backEnd.setPolicy(policy);
}
private V getValue(final Object cachedValue) {
if (cachedValue instanceof Fault) {
return ((Fault)cachedValue).get();
} else {
return (V)cachedValue;
}
}
/**
* Document me
*
* @param
*/
@IgnoreSizeOf
private static class Fault {
private final Callable source;
private V value;
private Throwable throwable;
private boolean complete;
public Fault(final Callable source) {
this.source = source;
}
private void complete(V value) {
synchronized (this) {
this.value = value;
this.complete = true;
notifyAll();
}
}
private V get() {
synchronized (this) {
if (!complete) {
try {
complete(source.call());
} catch (Throwable e) {
fail(e);
}
}
}
return throwOrReturn();
}
private V throwOrReturn() {
if (throwable != null) {
if (throwable instanceof RuntimeException) {
throw (RuntimeException) throwable;
}
throw new CacheException("Faulting from repository failed", throwable);
}
return value;
}
private void fail(final Throwable t) {
synchronized (this) {
this.throwable = t;
this.complete = true;
notifyAll();
}
throwOrReturn();
}
}
}