Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/3663#discussion_r113207820
--- Diff:
flink-connectors/flink-connector-kafka-base/src/main/java/org/apache/flink/streaming/connectors/kafka/KafkaAvroTableSource.java
---
@@ -0,0 +1,117 @@
+/*
+ * 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.streaming.connectors.kafka;
+
+import java.util.List;
+import java.util.Properties;
+import org.apache.avro.Schema;
+import org.apache.avro.specific.SpecificData;
+import org.apache.avro.specific.SpecificRecord;
+import org.apache.avro.specific.SpecificRecordBase;
+import org.apache.avro.util.Utf8;
+import org.apache.flink.api.common.typeinfo.BasicTypeInfo;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.api.java.typeutils.AvroTypeInfo;
+import org.apache.flink.api.java.typeutils.GenericTypeInfo;
+import org.apache.flink.api.java.typeutils.RowTypeInfo;
+import
org.apache.flink.streaming.util.serialization.AvroRowDeserializationSchema;
+import org.apache.flink.streaming.util.serialization.DeserializationSchema;
+import org.apache.flink.table.sources.StreamTableSource;
+
+/**
+ * A version-agnostic Kafka Avro {@link StreamTableSource}.
+ *
+ * <p>The version-specific Kafka consumers need to extend this class and
+ * override {@link #getKafkaConsumer(String, Properties,
DeserializationSchema)}}.
+ */
+public abstract class KafkaAvroTableSource extends KafkaTableSource {
+
+ /**
+ * Creates a generic Kafka Avro {@link StreamTableSource} using a given
{@link SpecificRecord}.
+ *
+ * @param topic Kafka topic to consume.
+ * @param properties Properties for the Kafka consumer.
+ * @param record Avro specific record.
+ */
+ KafkaAvroTableSource(
+ String topic,
+ Properties properties,
+ Class<? extends SpecificRecordBase> record) {
+
+ super(
+ topic,
+ properties,
+ createDeserializationSchema(record),
+ createFieldNames(record),
+ createFieldTypes(record));
+ }
+
+ private static AvroRowDeserializationSchema
createDeserializationSchema(Class<? extends SpecificRecordBase> record) {
+ return new AvroRowDeserializationSchema(record);
+ }
+
+ /**
+ * Converts the extracted AvroTypeInfo into a RowTypeInfo nested
structure with deterministic field order.
+ * Replaces generic Utf8 with basic String type information.
+ */
+ private static TypeInformation<?>
convertToRowTypeInformation(TypeInformation<?> extracted, Schema schema) {
+ if (schema.getType() == Schema.Type.RECORD) {
+ final List<Schema.Field> fields = schema.getFields();
+ final AvroTypeInfo<?> avroTypeInfo = (AvroTypeInfo<?>)
extracted;
+
+ final TypeInformation<?>[] types = new
TypeInformation<?>[fields.size()];
+ final String[] names = new String[fields.size()];
+ for (int i = 0; i < fields.size(); i++) {
+ final Schema.Field field = fields.get(i);
+ types[i] =
convertToRowTypeInformation(avroTypeInfo.getTypeAt(field.name()),
field.schema());
+ names[i] = field.name();
+ }
+ return new RowTypeInfo(types, names);
+ } else if (extracted instanceof GenericTypeInfo<?>) {
+ final GenericTypeInfo<?> genericTypeInfo =
(GenericTypeInfo<?>) extracted;
+ if (genericTypeInfo.getTypeClass() == Utf8.class) {
+ return BasicTypeInfo.STRING_TYPE_INFO;
+ }
+ }
+ return extracted;
+ }
+
+ private static <T extends SpecificRecordBase> TypeInformation<?>[]
createFieldTypes(Class<T> record) {
--- End diff --
This method can be removed as well, if we refactor `KafkaTableSource` as
described below.
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