Yuta HIGUCHI | b5df76d | 2014-09-27 20:54:00 -0700 | [diff] [blame] | 1 | package org.onlab.onos.store.common; |
Yuta HIGUCHI | 951e790 | 2014-09-23 14:45:11 -0700 | [diff] [blame] | 2 | |
| 3 | import static com.google.common.base.Preconditions.checkNotNull; |
| 4 | |
Yuta HIGUCHI | 672488d | 2014-10-07 09:23:43 -0700 | [diff] [blame] | 5 | import org.onlab.onos.store.serializers.Serializer; |
Yuta HIGUCHI | ad4c218 | 2014-09-29 11:16:23 -0700 | [diff] [blame] | 6 | |
Yuta HIGUCHI | 951e790 | 2014-09-23 14:45:11 -0700 | [diff] [blame] | 7 | import com.google.common.base.Optional; |
| 8 | import com.google.common.cache.CacheLoader; |
| 9 | import com.hazelcast.core.IMap; |
| 10 | |
| 11 | /** |
| 12 | * CacheLoader to wrap Map value with Optional, |
| 13 | * to handle negative hit on underlying IMap. |
| 14 | * |
| 15 | * @param <K> IMap key type after deserialization |
| 16 | * @param <V> IMap value type after deserialization |
| 17 | */ |
| 18 | public final class OptionalCacheLoader<K, V> extends |
| 19 | CacheLoader<K, Optional<V>> { |
| 20 | |
Yuta HIGUCHI | 672488d | 2014-10-07 09:23:43 -0700 | [diff] [blame] | 21 | private final Serializer serializer; |
Yuta HIGUCHI | 951e790 | 2014-09-23 14:45:11 -0700 | [diff] [blame] | 22 | private IMap<byte[], byte[]> rawMap; |
| 23 | |
| 24 | /** |
| 25 | * Constructor. |
| 26 | * |
Yuta HIGUCHI | 672488d | 2014-10-07 09:23:43 -0700 | [diff] [blame] | 27 | * @param serializer to use for serialization |
Yuta HIGUCHI | 951e790 | 2014-09-23 14:45:11 -0700 | [diff] [blame] | 28 | * @param rawMap underlying IMap |
| 29 | */ |
Yuta HIGUCHI | 672488d | 2014-10-07 09:23:43 -0700 | [diff] [blame] | 30 | public OptionalCacheLoader(Serializer serializer, IMap<byte[], byte[]> rawMap) { |
| 31 | this.serializer = checkNotNull(serializer); |
Yuta HIGUCHI | 951e790 | 2014-09-23 14:45:11 -0700 | [diff] [blame] | 32 | this.rawMap = checkNotNull(rawMap); |
| 33 | } |
| 34 | |
| 35 | @Override |
| 36 | public Optional<V> load(K key) throws Exception { |
Yuta HIGUCHI | 672488d | 2014-10-07 09:23:43 -0700 | [diff] [blame] | 37 | byte[] keyBytes = serializer.encode(key); |
Yuta HIGUCHI | 951e790 | 2014-09-23 14:45:11 -0700 | [diff] [blame] | 38 | byte[] valBytes = rawMap.get(keyBytes); |
| 39 | if (valBytes == null) { |
| 40 | return Optional.absent(); |
| 41 | } |
Yuta HIGUCHI | 672488d | 2014-10-07 09:23:43 -0700 | [diff] [blame] | 42 | V dev = serializer.decode(valBytes); |
Yuta HIGUCHI | 951e790 | 2014-09-23 14:45:11 -0700 | [diff] [blame] | 43 | return Optional.of(dev); |
| 44 | } |
| 45 | } |