| /* |
| * 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 |
| * |
| * https://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.avro.hadoop.io; |
| |
| import java.lang.reflect.Constructor; |
| import java.util.Collection; |
| |
| import org.apache.avro.Schema; |
| import org.apache.avro.generic.GenericData; |
| import org.apache.avro.io.DatumReader; |
| import org.apache.avro.io.DatumWriter; |
| import org.apache.avro.mapred.AvroKey; |
| import org.apache.avro.mapred.AvroValue; |
| import org.apache.avro.mapred.AvroWrapper; |
| import org.apache.avro.reflect.ReflectData; |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.hadoop.conf.Configured; |
| import org.apache.hadoop.io.serializer.Deserializer; |
| import org.apache.hadoop.io.serializer.Serialization; |
| import org.apache.hadoop.io.serializer.Serializer; |
| import org.apache.hadoop.util.ReflectionUtils; |
| |
| /** |
| * The {@link org.apache.hadoop.io.serializer.Serialization} used by jobs |
| * configured with {@link org.apache.avro.mapreduce.AvroJob}. |
| * |
| * @param <T> The Java type of the Avro data to serialize. |
| */ |
| public class AvroSerialization<T> extends Configured implements Serialization<AvroWrapper<T>> { |
| /** |
| * Conf key for the writer schema of the AvroKey datum being |
| * serialized/deserialized. |
| */ |
| private static final String CONF_KEY_WRITER_SCHEMA = "avro.serialization.key.writer.schema"; |
| |
| /** |
| * Conf key for the reader schema of the AvroKey datum being |
| * serialized/deserialized. |
| */ |
| private static final String CONF_KEY_READER_SCHEMA = "avro.serialization.key.reader.schema"; |
| |
| /** |
| * Conf key for the writer schema of the AvroValue datum being |
| * serialized/deserialized. |
| */ |
| private static final String CONF_VALUE_WRITER_SCHEMA = "avro.serialization.value.writer.schema"; |
| |
| /** |
| * Conf key for the reader schema of the AvroValue datum being |
| * serialized/deserialized. |
| */ |
| private static final String CONF_VALUE_READER_SCHEMA = "avro.serialization.value.reader.schema"; |
| |
| /** Conf key for the data model implementation class. */ |
| private static final String CONF_DATA_MODEL = "avro.serialization.data.model"; |
| |
| /** {@inheritDoc} */ |
| @Override |
| public boolean accept(Class<?> c) { |
| return AvroKey.class.isAssignableFrom(c) || AvroValue.class.isAssignableFrom(c); |
| } |
| |
| /** |
| * Gets an object capable of deserializing the output from a Mapper. |
| * |
| * @param c The class to get a deserializer for. |
| * @return A deserializer for objects of class <code>c</code>. |
| */ |
| @Override |
| public Deserializer<AvroWrapper<T>> getDeserializer(Class<AvroWrapper<T>> c) { |
| Configuration conf = getConf(); |
| GenericData dataModel = createDataModel(conf); |
| if (AvroKey.class.isAssignableFrom(c)) { |
| Schema writerSchema = getKeyWriterSchema(conf); |
| Schema readerSchema = getKeyReaderSchema(conf); |
| DatumReader<T> datumReader = (readerSchema != null) ? dataModel.createDatumReader(writerSchema, readerSchema) |
| : dataModel.createDatumReader(writerSchema); |
| return new AvroKeyDeserializer<>(writerSchema, readerSchema, datumReader); |
| } else if (AvroValue.class.isAssignableFrom(c)) { |
| Schema writerSchema = getValueWriterSchema(conf); |
| Schema readerSchema = getValueReaderSchema(conf); |
| DatumReader<T> datumReader = (readerSchema != null) ? dataModel.createDatumReader(writerSchema, readerSchema) |
| : dataModel.createDatumReader(writerSchema); |
| return new AvroValueDeserializer<>(writerSchema, readerSchema, datumReader); |
| } else { |
| throw new IllegalStateException("Only AvroKey and AvroValue are supported."); |
| } |
| } |
| |
| /** |
| * Gets an object capable of serializing output from a Mapper. |
| * |
| * @param c The class to get a serializer for. |
| * @return A serializer for objects of class <code>c</code>. |
| */ |
| @Override |
| public Serializer<AvroWrapper<T>> getSerializer(Class<AvroWrapper<T>> c) { |
| Configuration conf = getConf(); |
| Schema schema; |
| if (AvroKey.class.isAssignableFrom(c)) { |
| schema = getKeyWriterSchema(conf); |
| } else if (AvroValue.class.isAssignableFrom(c)) { |
| schema = getValueWriterSchema(conf); |
| } else { |
| throw new IllegalStateException("Only AvroKey and AvroValue are supported."); |
| } |
| GenericData dataModel = createDataModel(conf); |
| DatumWriter<T> datumWriter = dataModel.createDatumWriter(schema); |
| return new AvroSerializer<>(schema, datumWriter); |
| } |
| |
| /** |
| * Adds the AvroSerialization scheme to the configuration, so |
| * SerializationFactory instances constructed from the given configuration will |
| * be aware of it. |
| * |
| * @param conf The configuration to add AvroSerialization to. |
| */ |
| public static void addToConfiguration(Configuration conf) { |
| Collection<String> serializations = conf.getStringCollection("io.serializations"); |
| if (!serializations.contains(AvroSerialization.class.getName())) { |
| serializations.add(AvroSerialization.class.getName()); |
| conf.setStrings("io.serializations", serializations.toArray(new String[0])); |
| } |
| } |
| |
| /** |
| * Sets the writer schema of the AvroKey datum that is being |
| * serialized/deserialized. |
| * |
| * @param conf The configuration. |
| * @param schema The Avro key schema. |
| */ |
| public static void setKeyWriterSchema(Configuration conf, Schema schema) { |
| if (null == schema) { |
| throw new IllegalArgumentException("Writer schema may not be null"); |
| } |
| conf.set(CONF_KEY_WRITER_SCHEMA, schema.toString()); |
| } |
| |
| /** |
| * Sets the reader schema of the AvroKey datum that is being |
| * serialized/deserialized. |
| * |
| * @param conf The configuration. |
| * @param schema The Avro key schema. |
| */ |
| public static void setKeyReaderSchema(Configuration conf, Schema schema) { |
| conf.set(CONF_KEY_READER_SCHEMA, schema.toString()); |
| } |
| |
| /** |
| * Sets the writer schema of the AvroValue datum that is being |
| * serialized/deserialized. |
| * |
| * @param conf The configuration. |
| * @param schema The Avro value schema. |
| */ |
| public static void setValueWriterSchema(Configuration conf, Schema schema) { |
| if (null == schema) { |
| throw new IllegalArgumentException("Writer schema may not be null"); |
| } |
| conf.set(CONF_VALUE_WRITER_SCHEMA, schema.toString()); |
| } |
| |
| /** |
| * Sets the reader schema of the AvroValue datum that is being |
| * serialized/deserialized. |
| * |
| * @param conf The configuration. |
| * @param schema The Avro value schema. |
| */ |
| public static void setValueReaderSchema(Configuration conf, Schema schema) { |
| conf.set(CONF_VALUE_READER_SCHEMA, schema.toString()); |
| } |
| |
| /** |
| * Sets the data model class for de/serialization. |
| * |
| * @param conf The configuration. |
| * @param modelClass The data model class. |
| */ |
| public static void setDataModelClass(Configuration conf, Class<? extends GenericData> modelClass) { |
| conf.setClass(CONF_DATA_MODEL, modelClass, GenericData.class); |
| } |
| |
| /** |
| * Gets the writer schema of the AvroKey datum that is being |
| * serialized/deserialized. |
| * |
| * @param conf The configuration. |
| * @return The Avro key writer schema, or null if none was set. |
| */ |
| public static Schema getKeyWriterSchema(Configuration conf) { |
| String json = conf.get(CONF_KEY_WRITER_SCHEMA); |
| return null == json ? null : new Schema.Parser().parse(json); |
| } |
| |
| /** |
| * Gets the reader schema of the AvroKey datum that is being |
| * serialized/deserialized. |
| * |
| * @param conf The configuration. |
| * @return The Avro key reader schema, or null if none was set. |
| */ |
| public static Schema getKeyReaderSchema(Configuration conf) { |
| String json = conf.get(CONF_KEY_READER_SCHEMA); |
| return null == json ? null : new Schema.Parser().parse(json); |
| } |
| |
| /** |
| * Gets the writer schema of the AvroValue datum that is being |
| * serialized/deserialized. |
| * |
| * @param conf The configuration. |
| * @return The Avro value writer schema, or null if none was set. |
| */ |
| public static Schema getValueWriterSchema(Configuration conf) { |
| String json = conf.get(CONF_VALUE_WRITER_SCHEMA); |
| return null == json ? null : new Schema.Parser().parse(json); |
| } |
| |
| /** |
| * Gets the reader schema of the AvroValue datum that is being |
| * serialized/deserialized. |
| * |
| * @param conf The configuration. |
| * @return The Avro value reader schema, or null if none was set. |
| */ |
| public static Schema getValueReaderSchema(Configuration conf) { |
| String json = conf.get(CONF_VALUE_READER_SCHEMA); |
| return null == json ? null : new Schema.Parser().parse(json); |
| } |
| |
| /** |
| * Gets the data model class for de/serialization. |
| * |
| * @param conf The configuration. |
| */ |
| public static Class<? extends GenericData> getDataModelClass(Configuration conf) { |
| return conf.getClass(CONF_DATA_MODEL, ReflectData.class, GenericData.class); |
| } |
| |
| private static GenericData newDataModelInstance(Class<? extends GenericData> modelClass, Configuration conf) { |
| GenericData dataModel; |
| try { |
| Constructor<? extends GenericData> ctor = modelClass.getDeclaredConstructor(ClassLoader.class); |
| ctor.setAccessible(true); |
| dataModel = ctor.newInstance(conf.getClassLoader()); |
| } catch (Exception e) { |
| throw new RuntimeException(e); |
| } |
| ReflectionUtils.setConf(dataModel, conf); |
| return dataModel; |
| } |
| |
| /** |
| * Gets an instance of data model implementation, defaulting to |
| * {@link ReflectData} if not explicitly specified. |
| * |
| * @param conf The job configuration. |
| * @return Instance of the job data model implementation. |
| */ |
| public static GenericData createDataModel(Configuration conf) { |
| Class<? extends GenericData> modelClass = getDataModelClass(conf); |
| return newDataModelInstance(modelClass, conf); |
| } |
| } |