tzulitai commented on a change in pull request #17: [FLINK-15954] Add a PersistedTable to the SDK URL: https://github.com/apache/flink-statefun/pull/17#discussion_r376679741
########## File path: statefun-flink/statefun-flink-core/src/main/java/org/apache/flink/statefun/flink/core/state/MultiplexedTableStateAccessor.java ########## @@ -0,0 +1,141 @@ +/* + * 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.flink.statefun.flink.core.state; + +import com.google.protobuf.ByteString; +import java.io.IOException; +import java.util.Objects; +import javax.annotation.Nonnull; +import javax.annotation.Nullable; +import org.apache.flink.api.common.state.MapState; +import org.apache.flink.api.common.typeutils.TypeSerializer; +import org.apache.flink.core.memory.DataInputDeserializer; +import org.apache.flink.core.memory.DataOutputSerializer; +import org.apache.flink.statefun.flink.core.cache.SingleThreadedLruCache; +import org.apache.flink.statefun.flink.core.generated.MultiplexedStateKey; +import org.apache.flink.statefun.sdk.state.TableAccessor; + +final class MultiplexedTableStateAccessor<K, V> implements TableAccessor<K, V> { + private final MapState<MultiplexedStateKey, byte[]> mapStateHandle; + private final MultiplexedStateKey accessorMapKeyPrefix; + private final TaggedRawSerializer<K> keySerializer; + private final TaggedRawSerializer<V> valueSerializer; + + private final SingleThreadedLruCache<K, MultiplexedStateKey> commonKeysCache = + new SingleThreadedLruCache<>(128); + + MultiplexedTableStateAccessor( + MapState<MultiplexedStateKey, byte[]> handle, + MultiplexedStateKey accessorMapKeyPrefix, + TypeSerializer<K> subKeySerializer, + TypeSerializer<V> subValueSerializer) { + this.mapStateHandle = Objects.requireNonNull(handle); + this.keySerializer = new TaggedRawSerializer<>(new byte[0], subKeySerializer); + this.valueSerializer = new TaggedRawSerializer<>(new byte[0], subValueSerializer); + this.accessorMapKeyPrefix = accessorMapKeyPrefix; + } + + @Override + public void set(K key, V value) { + try { + MultiplexedStateKey keyBytes = stateKey(key); + if (value == null) { + mapStateHandle.remove(keyBytes); + } else { + byte[] bytes = valueSerializer.serialize(value); + mapStateHandle.put(keyBytes, bytes); + } + } catch (Exception e) { + throw new RuntimeException(e); + } + } + + @Override + public V get(K userKey) { + try { + final MultiplexedStateKey stateKey = stateKey(userKey); + final byte[] bytes = mapStateHandle.get(stateKey); + if (bytes == null) { + return null; + } + return valueSerializer.deserialize(bytes); + } catch (Exception e) { + throw new RuntimeException(e); + } + } + + @Override + public void remove(K userKey) { + try { + mapStateHandle.remove(stateKey(userKey)); + } catch (Exception e) { + throw new RuntimeException(e); + } + } + + @Nonnull + private MultiplexedStateKey stateKey(final K userKey) { + Objects.requireNonNull(userKey, "Key can not be NULL"); + @Nullable MultiplexedStateKey stateKey = commonKeysCache.get(userKey); + if (stateKey != null) { + return stateKey; + } + try { + commonKeysCache.put(userKey, stateKey = computeStateKeyFromUserKey(userKey)); + return stateKey; + } catch (IOException e) { + throw new RuntimeException("Unable to serialize the key " + userKey, e); + } + } + + private MultiplexedStateKey computeStateKeyFromUserKey(K userKey) throws IOException { + byte[] userKeyBytes = keySerializer.serialize(userKey); + ByteString userKeyByteString = ByteString.copyFrom(userKeyBytes); + return accessorMapKeyPrefix.toBuilder().addUserKeys(userKeyByteString).build(); + } + + private static final class TaggedRawSerializer<T> { + + private final TypeSerializer<T> delegate; + private final DataOutputSerializer output; + private final DataInputDeserializer input; + private final byte[] tag; + + TaggedRawSerializer(byte[] tag, TypeSerializer<T> delegate) { + this.tag = Objects.requireNonNull(tag); + this.delegate = Objects.requireNonNull(delegate); + this.output = new DataOutputSerializer(32 + tag.length); + this.input = new DataInputDeserializer(); + } + + byte[] serialize(T value) throws IOException { + output.clear(); + output.write(tag); + delegate.serialize(value, output); + return output.getCopyOfBuffer(); // TODO: consider avoiding buffer copying Review comment: If we want this TODO to be merged, we should probably open a JIRA for it. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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