Github user StephanEwen commented on a diff in the pull request:
https://github.com/apache/flink/pull/5995#discussion_r188321914
--- Diff:
flink-formats/flink-avro-confluent-registry/src/main/java/org/apache/flink/formats/avro/registry/confluent/ConfluentRegistryAvroDeserializationSchema.java
---
@@ -0,0 +1,137 @@
+/*
+ * 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.formats.avro.registry.confluent;
+
+import org.apache.flink.formats.avro.AvroDeserializationSchema;
+import org.apache.flink.formats.avro.RegistryAvroDeserializationSchema;
+import org.apache.flink.formats.avro.SchemaCoder;
+
+import io.confluent.kafka.schemaregistry.client.CachedSchemaRegistryClient;
+import org.apache.avro.Schema;
+import org.apache.avro.generic.GenericRecord;
+import org.apache.avro.specific.SpecificRecord;
+
+import javax.annotation.Nullable;
+
+/**
+ * Deserialization schema that deserializes from Avro binary format using
{@link SchemaCoder} that uses
+ * Confluent Schema Registry.
+ *
+ * @param <T> type of record it produces
+ */
+public class ConfluentRegistryAvroDeserializationSchema<T>
+ extends RegistryAvroDeserializationSchema<T> {
+
+ private static final int DEFAULT_IDENTITY_MAP_CAPACITY = 1000;
+
+ /**
+ * Creates a Avro deserialization schema.
+ *
+ * @param recordClazz class to which deserialize. Should be
either
+ * {@link SpecificRecord} or {@link
GenericRecord}.
+ * @param reader reader's Avro schema. Should be provided
if recordClazz is
+ * {@link GenericRecord}
+ * @param schemaCoderProvider provider for schema coder that reads
writer schema from Confluent Schema Registry
+ */
+ private ConfluentRegistryAvroDeserializationSchema(
+ Class<T> recordClazz,
+ @Nullable Schema reader,
+ SchemaCoder.SchemaCoderProvider schemaCoderProvider) {
+ super(recordClazz, reader, schemaCoderProvider);
+ }
+
+ /**
+ * Creates {@link ConfluentRegistryAvroDeserializationSchema} that
produces {@link GenericRecord}
+ * using provided reader schema and looks up writer schema in Confluent
Schema Registry.
+ *
+ * @param schema schema of produced records
+ * @param url url of schema registry to connect
+ * @return deserialized record in form of {@link GenericRecord}
+ */
+ public static ConfluentRegistryAvroDeserializationSchema<GenericRecord>
forGeneric(
+ Schema schema, String url) {
+ return forGeneric(schema, url, DEFAULT_IDENTITY_MAP_CAPACITY);
+ }
+
+ /**
+ * Creates {@link ConfluentRegistryAvroDeserializationSchema} that
produces {@link GenericRecord}
+ * using provided reader schema and looks up writer schema in Confluent
Schema Registry.
+ *
+ * @param schema schema of produced records
+ * @param url url of schema registry to connect
+ * @param identityMapCapacity maximum number of cached schema versions
(default: 1000)
+ * @return deserialized record in form of {@link GenericRecord}
+ */
+ public static ConfluentRegistryAvroDeserializationSchema<GenericRecord>
forGeneric(
+ Schema schema, String url, int identityMapCapacity) {
+ return new ConfluentRegistryAvroDeserializationSchema<>(
+ GenericRecord.class,
+ schema,
+ new CachedSchemaCoderProvider(url,
identityMapCapacity));
+ }
+
+ /**
+ * Creates {@link AvroDeserializationSchema} that produces classes that
were generated from avro
+ * schema and looks up writer schema in Confluent Schema Registry.
+ *
+ * @param tClass class of record to be produced
+ * @param url url of schema registry to connect
+ * @return deserialized record
+ */
+ public static <T extends SpecificRecord>
ConfluentRegistryAvroDeserializationSchema<T> forSpecific(
+ Class<T> tClass, String url) {
+ return forSpecific(tClass, url, DEFAULT_IDENTITY_MAP_CAPACITY);
+ }
+
+ /**
+ * Creates {@link AvroDeserializationSchema} that produces classes that
were generated from avro
+ * schema and looks up writer schema in Confluent Schema Registry.
+ *
+ * @param tClass class of record to be produced
+ * @param url url of schema registry to connect
+ * @param identityMapCapacity maximum number of cached schema versions
(default: 1000)
+ * @return deserialized record
+ */
+ public static <T extends SpecificRecord>
ConfluentRegistryAvroDeserializationSchema<T> forSpecific(
+ Class<T> tClass, String url, int identityMapCapacity) {
+ return new ConfluentRegistryAvroDeserializationSchema<>(
+ tClass,
+ null,
+ new CachedSchemaCoderProvider(url, identityMapCapacity)
+ );
+ }
+
+ private static class CachedSchemaCoderProvider implements
SchemaCoder.SchemaCoderProvider {
+
+ private final String url;
+ private final int identityMapCapacity;
+
+ private CachedSchemaCoderProvider(String url, int
identityMapCapacity) {
--- End diff --
Private constructor in an inner class requires a bridge constructor or the
compiler needs to change the visibility. I think it is good practice to give
inner classes package-private constructors.
---
