| /* |
| * 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.nifi.distributed.cache.client.adapter; |
| |
| import io.netty.buffer.ByteBuf; |
| import io.netty.buffer.Unpooled; |
| import org.apache.nifi.distributed.cache.client.AtomicCacheEntry; |
| import org.apache.nifi.distributed.cache.client.Deserializer; |
| |
| import java.io.IOException; |
| |
| /** |
| * Implementation of {@link InboundAdapter} where the service response payload is expected to be |
| * an {@link AtomicCacheEntry}, allowing for synchronized access to a given service cache entry. |
| * |
| * @param <K> the expected type of the service response key |
| * @param <V> the expected type of the service response value |
| */ |
| |
| public class AtomicCacheEntryInboundAdapter<K, V> implements InboundAdapter { |
| |
| /** |
| * The key of the requested service map entry. |
| */ |
| private final K key; |
| |
| /** |
| * The deserializer to be used to construct the value from the service response object. |
| */ |
| private final Deserializer<V> deserializer; |
| |
| /** |
| * Container for bytes queued from the service response {@link io.netty.channel.Channel}. |
| */ |
| private final ByteBuf byteBuf; |
| |
| /** |
| * The state of receipt of an individual service response token. |
| */ |
| private final InboundToken<V> inboundToken; |
| |
| /** |
| * The cache revision of the requested object. |
| */ |
| private Long revision; |
| |
| /** |
| * The cache entry reassembled from the service response. |
| */ |
| private AtomicCacheEntry<K, V, Long> result; |
| |
| /** |
| * Constructor. |
| * |
| * @param key the key of the requested service cache map entry |
| * @param deserializer the deserializer to be used to construct the service response map value |
| */ |
| public AtomicCacheEntryInboundAdapter(final K key, final Deserializer<V> deserializer) { |
| this.key = key; |
| this.deserializer = deserializer; |
| this.byteBuf = Unpooled.buffer(); |
| this.inboundToken = new InboundToken<>(); |
| this.revision = null; |
| this.result = null; |
| } |
| |
| /** |
| * @return the service method response value |
| */ |
| public AtomicCacheEntry<K, V, Long> getResult() { |
| return result; |
| } |
| |
| @Override |
| public boolean isComplete() { |
| return inboundToken.isComplete(); |
| } |
| |
| @Override |
| public void queue(final byte[] bytes) { |
| byteBuf.writeBytes(bytes); |
| } |
| |
| @Override |
| public void dequeue() throws IOException { |
| if ((revision == null) && (byteBuf.readableBytes() >= Long.BYTES)) { |
| revision = byteBuf.readLong(); |
| } |
| if (revision != null) { |
| inboundToken.update(byteBuf, deserializer); |
| if (inboundToken.isComplete()) { |
| result = (revision < 0) ? null : new AtomicCacheEntry<>(key, inboundToken.getValue(), revision); |
| } |
| } |
| } |
| } |