Java tutorial
/* * 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.bookkeeper.statelib.impl.kv; import io.netty.buffer.ByteBuf; import io.netty.buffer.ByteBufUtil; import io.netty.buffer.Unpooled; import java.io.IOException; import java.util.concurrent.CompletableFuture; import java.util.function.Supplier; import org.apache.bookkeeper.common.coder.Coder; import org.apache.bookkeeper.common.concurrent.FutureUtils; import org.apache.bookkeeper.proto.statestore.kv.Command; import org.apache.bookkeeper.statelib.api.StateStoreSpec; import org.apache.bookkeeper.statelib.api.exceptions.InvalidStateStoreException; import org.apache.bookkeeper.statelib.api.kv.KVAsyncStore; import org.apache.bookkeeper.statelib.impl.journal.AbstractStateStoreWithJournal; import org.apache.bookkeeper.statelib.impl.journal.CommandProcessor; import org.apache.distributedlog.api.namespace.Namespace; /** * A async kv store implementation. */ public class RocksdbKVAsyncStore<K, V> extends AbstractStateStoreWithJournal<RocksdbKVStore<byte[], byte[]>> implements KVAsyncStore<K, V> { private static final byte[] CATCHUP_MARKER = new byte[0]; private Coder<K> keyCoder; private Coder<V> valCoder; public RocksdbKVAsyncStore(Supplier<RocksdbKVStore<byte[], byte[]>> localStateStoreSupplier, Supplier<Namespace> namespaceSupplier) { super(localStateStoreSupplier, namespaceSupplier); } @SuppressWarnings("unchecked") @Override public CompletableFuture<Void> init(StateStoreSpec spec) { this.keyCoder = (Coder<K>) spec.getKeyCoder(); this.valCoder = (Coder<V>) spec.getValCoder(); return super.init(spec); } @Override public CompletableFuture<V> get(K key) { synchronized (this) { if (!isInitialized) { return uninitializedException(); } } return executeReadIO(() -> { byte[] keyBytes = keyCoder.encode(key); byte[] valBytes = localStore.get(keyBytes); if (null == valBytes) { return null; } else { return KVUtils.deserialize(valCoder, Unpooled.wrappedBuffer(valBytes)); } }); } @Override public CompletableFuture<Void> put(K key, V value) { synchronized (this) { if (!isInitialized) { return uninitializedException(); } } byte[] keyBytes = keyCoder.encode(key); byte[] valBytes = valCoder.encode(value); Command command = Command.newBuilder().setPutReq(KVUtils.newPutRequest(keyBytes, valBytes)).build(); return writeCommandReturnTxId(command).thenApplyAsync((revision) -> { ByteBuf serializedBuf = KVUtils.serialize(valBytes, revision); try { byte[] serializedBytes = ByteBufUtil.getBytes(serializedBuf); localStore.put(keyBytes, serializedBytes, revision); } finally { serializedBuf.release(); } return null; }, writeIOScheduler); } @Override public CompletableFuture<V> putIfAbsent(K key, V value) { byte[] keyBytes = keyCoder.encode(key); byte[] valBytes = valCoder.encode(value); Command command = Command.newBuilder().setPutIfAbsentReq(KVUtils.newPutIfAbsentRequest(keyBytes, valBytes)) .build(); return writeCommandReturnTxId(command).thenApplyAsync((revision) -> { ByteBuf serializedBuf = KVUtils.serialize(valBytes, revision); try { byte[] serializedBytes = ByteBufUtil.getBytes(serializedBuf); byte[] prevValue = localStore.putIfAbsent(keyBytes, serializedBytes, revision); if (null == prevValue) { return null; } else { return KVUtils.deserialize(valCoder, Unpooled.wrappedBuffer(prevValue)); } } finally { serializedBuf.release(); } }, writeIOScheduler); } @Override public CompletableFuture<V> delete(K key) { byte[] keyBytes = keyCoder.encode(key); Command command = Command.newBuilder().setDelReq(KVUtils.newDeleteRequest(keyBytes)).build(); return writeCommandReturnTxId(command).thenApplyAsync((revision) -> { byte[] prevValue = localStore.delete(keyBytes, revision); if (null == prevValue) { return null; } else { return KVUtils.deserialize(valCoder, Unpooled.wrappedBuffer(prevValue)); } }, writeIOScheduler); } private <AnyT> CompletableFuture<AnyT> uninitializedException() { return FutureUtils .exception(new InvalidStateStoreException("State store " + name() + " is not initialized yet.")); } // // Journaled State Store interfaces // @Override protected ByteBuf newCatchupMarker() { return Unpooled.wrappedBuffer(CATCHUP_MARKER); } @Override protected CommandProcessor<RocksdbKVStore<byte[], byte[]>> newCommandProcessor() { return KVCommandProcessor.of(); } private CompletableFuture<Long> writeCommandReturnTxId(Command command) { try { ByteBuf cmdBuf = KVUtils.newCommandBuf(command); return writeCommandBufReturnTxId(cmdBuf); } catch (IOException e) { return FutureUtils.exception(e); } } }