| /* |
| * 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.cassandra.cache; |
| |
| import java.io.IOException; |
| import java.util.Iterator; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import com.googlecode.concurrentlinkedhashmap.ConcurrentLinkedHashMap; |
| import com.googlecode.concurrentlinkedhashmap.EvictionListener; |
| import com.googlecode.concurrentlinkedhashmap.Weigher; |
| |
| import org.apache.cassandra.io.ISerializer; |
| import org.apache.cassandra.io.util.MemoryInputStream; |
| import org.apache.cassandra.io.util.MemoryOutputStream; |
| import org.apache.cassandra.io.util.WrappedDataOutputStreamPlus; |
| import org.apache.cassandra.utils.FBUtilities; |
| |
| /** |
| * Serializes cache values off-heap. |
| */ |
| public class SerializingCache<K, V> implements ICache<K, V> |
| { |
| private static final Logger logger = LoggerFactory.getLogger(SerializingCache.class); |
| |
| private static final int DEFAULT_CONCURENCY_LEVEL = 64; |
| |
| private final ConcurrentLinkedHashMap<K, RefCountedMemory> map; |
| private final ISerializer<V> serializer; |
| |
| private SerializingCache(long capacity, Weigher<RefCountedMemory> weigher, ISerializer<V> serializer) |
| { |
| this.serializer = serializer; |
| |
| EvictionListener<K,RefCountedMemory> listener = new EvictionListener<K, RefCountedMemory>() |
| { |
| public void onEviction(K k, RefCountedMemory mem) |
| { |
| mem.unreference(); |
| } |
| }; |
| |
| this.map = new ConcurrentLinkedHashMap.Builder<K, RefCountedMemory>() |
| .weigher(weigher) |
| .maximumWeightedCapacity(capacity) |
| .concurrencyLevel(DEFAULT_CONCURENCY_LEVEL) |
| .listener(listener) |
| .build(); |
| } |
| |
| public static <K, V> SerializingCache<K, V> create(long weightedCapacity, Weigher<RefCountedMemory> weigher, ISerializer<V> serializer) |
| { |
| return new SerializingCache<>(weightedCapacity, weigher, serializer); |
| } |
| |
| public static <K, V> SerializingCache<K, V> create(long weightedCapacity, ISerializer<V> serializer) |
| { |
| return create(weightedCapacity, new Weigher<RefCountedMemory>() |
| { |
| public int weightOf(RefCountedMemory value) |
| { |
| long size = value.size(); |
| assert size < Integer.MAX_VALUE : "Serialized size cannot be more than 2GB"; |
| return (int) size; |
| } |
| }, serializer); |
| } |
| |
| private V deserialize(RefCountedMemory mem) |
| { |
| try |
| { |
| return serializer.deserialize(new MemoryInputStream(mem)); |
| } |
| catch (IOException e) |
| { |
| logger.trace("Cannot fetch in memory data, we will fallback to read from disk ", e); |
| return null; |
| } |
| } |
| |
| private RefCountedMemory serialize(V value) |
| { |
| long serializedSize = serializer.serializedSize(value); |
| if (serializedSize > Integer.MAX_VALUE) |
| throw new IllegalArgumentException(String.format("Unable to allocate %s", FBUtilities.prettyPrintMemory(serializedSize))); |
| |
| RefCountedMemory freeableMemory; |
| try |
| { |
| freeableMemory = new RefCountedMemory(serializedSize); |
| } |
| catch (OutOfMemoryError e) |
| { |
| return null; |
| } |
| |
| try |
| { |
| serializer.serialize(value, new WrappedDataOutputStreamPlus(new MemoryOutputStream(freeableMemory))); |
| } |
| catch (IOException e) |
| { |
| freeableMemory.unreference(); |
| throw new RuntimeException(e); |
| } |
| return freeableMemory; |
| } |
| |
| public long capacity() |
| { |
| return map.capacity(); |
| } |
| |
| public void setCapacity(long capacity) |
| { |
| map.setCapacity(capacity); |
| } |
| |
| public boolean isEmpty() |
| { |
| return map.isEmpty(); |
| } |
| |
| public int size() |
| { |
| return map.size(); |
| } |
| |
| public long weightedSize() |
| { |
| return map.weightedSize(); |
| } |
| |
| public void clear() |
| { |
| map.clear(); |
| } |
| |
| @SuppressWarnings("resource") |
| public V get(K key) |
| { |
| RefCountedMemory mem = map.get(key); |
| if (mem == null) |
| return null; |
| if (!mem.reference()) |
| return null; |
| try |
| { |
| return deserialize(mem); |
| } |
| finally |
| { |
| mem.unreference(); |
| } |
| } |
| |
| @SuppressWarnings("resource") |
| public void put(K key, V value) |
| { |
| RefCountedMemory mem = serialize(value); |
| if (mem == null) |
| return; // out of memory. never mind. |
| |
| RefCountedMemory old; |
| try |
| { |
| old = map.put(key, mem); |
| } |
| catch (Throwable t) |
| { |
| mem.unreference(); |
| throw t; |
| } |
| |
| if (old != null) |
| old.unreference(); |
| } |
| |
| @SuppressWarnings("resource") |
| public boolean putIfAbsent(K key, V value) |
| { |
| RefCountedMemory mem = serialize(value); |
| if (mem == null) |
| return false; // out of memory. never mind. |
| |
| RefCountedMemory old; |
| try |
| { |
| old = map.putIfAbsent(key, mem); |
| } |
| catch (Throwable t) |
| { |
| mem.unreference(); |
| throw t; |
| } |
| |
| if (old != null) |
| // the new value was not put, we've uselessly allocated some memory, free it |
| mem.unreference(); |
| return old == null; |
| } |
| |
| @SuppressWarnings("resource") |
| public boolean replace(K key, V oldToReplace, V value) |
| { |
| // if there is no old value in our map, we fail |
| RefCountedMemory old = map.get(key); |
| if (old == null) |
| return false; |
| |
| V oldValue; |
| // reference old guy before de-serializing |
| if (!old.reference()) |
| return false; // we have already freed hence noop. |
| |
| oldValue = deserialize(old); |
| old.unreference(); |
| |
| if (!oldValue.equals(oldToReplace)) |
| return false; |
| |
| // see if the old value matches the one we want to replace |
| RefCountedMemory mem = serialize(value); |
| if (mem == null) |
| return false; // out of memory. never mind. |
| |
| boolean success; |
| try |
| { |
| success = map.replace(key, old, mem); |
| } |
| catch (Throwable t) |
| { |
| mem.unreference(); |
| throw t; |
| } |
| |
| if (success) |
| old.unreference(); // so it will be eventually be cleaned |
| else |
| mem.unreference(); |
| return success; |
| } |
| |
| public void remove(K key) |
| { |
| @SuppressWarnings("resource") |
| RefCountedMemory mem = map.remove(key); |
| if (mem != null) |
| mem.unreference(); |
| } |
| |
| public Iterator<K> keyIterator() |
| { |
| return map.keySet().iterator(); |
| } |
| |
| public Iterator<K> hotKeyIterator(int n) |
| { |
| return map.descendingKeySetWithLimit(n).iterator(); |
| } |
| |
| public boolean containsKey(K key) |
| { |
| return map.containsKey(key); |
| } |
| } |