yeralin commented on a change in pull request #6592: URL: https://github.com/apache/kafka/pull/6592#discussion_r631339580
########## File path: clients/src/main/java/org/apache/kafka/common/serialization/ListDeserializer.java ########## @@ -0,0 +1,197 @@ +/* + * 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.kafka.common.serialization; + +import org.apache.kafka.clients.CommonClientConfigs; +import org.apache.kafka.common.KafkaException; +import org.apache.kafka.common.config.ConfigException; +import org.apache.kafka.common.errors.SerializationException; +import org.apache.kafka.common.utils.Utils; + +import java.io.ByteArrayInputStream; +import java.io.DataInputStream; +import java.io.IOException; +import java.lang.reflect.Constructor; +import java.lang.reflect.InvocationTargetException; +import java.util.ArrayList; +import java.util.List; +import java.util.Map; + +import static org.apache.kafka.common.serialization.Serdes.ListSerde.SerializationStrategy; +import static org.apache.kafka.common.utils.Utils.mkEntry; +import static org.apache.kafka.common.utils.Utils.mkMap; + +public class ListDeserializer<Inner> implements Deserializer<List<Inner>> { + + private static final Map<Class<? extends Deserializer<?>>, Integer> FIXED_LENGTH_DESERIALIZERS = mkMap( + mkEntry(ShortDeserializer.class, Short.BYTES), + mkEntry(IntegerDeserializer.class, Integer.BYTES), + mkEntry(FloatDeserializer.class, Float.BYTES), + mkEntry(LongDeserializer.class, Long.BYTES), + mkEntry(DoubleDeserializer.class, Double.BYTES), + mkEntry(UUIDDeserializer.class, 36) + ); + + private Deserializer<Inner> inner; + private Class<?> listClass; + private Integer primitiveSize; + + public ListDeserializer() {} + + public <L extends List<Inner>> ListDeserializer(Class<L> listClass, Deserializer<Inner> inner) { + if (listClass == null || inner == null) { + throw new IllegalArgumentException("ListDeserializer requires both \"listClass\" and \"innerDeserializer\" parameters to be provided during initialization"); + } + this.listClass = listClass; + this.inner = inner; + this.primitiveSize = FIXED_LENGTH_DESERIALIZERS.get(inner.getClass()); + } + + public Deserializer<Inner> getInnerDeserializer() { + return inner; + } + + @Override + public void configure(Map<String, ?> configs, boolean isKey) { + if (listClass != null || inner != null) { + throw new ConfigException("List deserializer was already initialized using a non-default constructor"); + } + configureListClass(configs, isKey); + configureInnerSerde(configs, isKey); + } + + private void configureListClass(Map<String, ?> configs, boolean isKey) { + String listTypePropertyName = isKey ? CommonClientConfigs.DEFAULT_LIST_KEY_SERDE_TYPE_CLASS : CommonClientConfigs.DEFAULT_LIST_VALUE_SERDE_TYPE_CLASS; + final Object listClassOrName = configs.get(listTypePropertyName); + if (listClassOrName == null) { + throw new ConfigException("Not able to determine the list class because it was neither passed via the constructor nor set in the config."); + } + try { + if (listClassOrName instanceof String) { + listClass = Utils.loadClass((String) listClassOrName, Object.class); + } else if (listClassOrName instanceof Class) { + listClass = (Class<?>) listClassOrName; + } else { + throw new KafkaException("Could not determine the list class instance using \"" + listTypePropertyName + "\" property."); + } + } catch (final ClassNotFoundException e) { + throw new ConfigException(listTypePropertyName, listClassOrName, "Deserializer's list class \"" + listClassOrName + "\" could not be found."); + } + } + + @SuppressWarnings("unchecked") + private void configureInnerSerde(Map<String, ?> configs, boolean isKey) { + String innerSerdePropertyName = isKey ? CommonClientConfigs.DEFAULT_LIST_KEY_SERDE_INNER_CLASS : CommonClientConfigs.DEFAULT_LIST_VALUE_SERDE_INNER_CLASS; + final Object innerSerdeClassOrName = configs.get(innerSerdePropertyName); + if (innerSerdeClassOrName == null) { + throw new ConfigException("Not able to determine the inner serde class because it was neither passed via the constructor nor set in the config."); + } + try { + if (innerSerdeClassOrName instanceof String) { + inner = Utils.newInstance((String) innerSerdeClassOrName, Serde.class).deserializer(); + } else if (innerSerdeClassOrName instanceof Class) { + inner = (Deserializer<Inner>) ((Serde) Utils.newInstance((Class) innerSerdeClassOrName)).deserializer(); + } else { + throw new KafkaException("Could not determine the inner serde class instance using \"" + innerSerdePropertyName + "\" property."); + } + inner.configure(configs, isKey); + primitiveSize = FIXED_LENGTH_DESERIALIZERS.get(inner.getClass()); + } catch (final ClassNotFoundException e) { + throw new ConfigException(innerSerdePropertyName, innerSerdeClassOrName, "Deserializer's inner serde class \"" + innerSerdeClassOrName + "\" could not be found."); + } + } + Review comment: Omg I am blind. 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