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https://issues.apache.org/jira/browse/FLINK-8240?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16334946#comment-16334946
]
ASF GitHub Bot commented on FLINK-8240:
---------------------------------------
Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/5240#discussion_r163012442
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/descriptors/StreamTableSourceDescriptor.scala
---
@@ -0,0 +1,95 @@
+/*
+ * 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.table.descriptors
+
+import org.apache.flink.table.api.{StreamTableEnvironment, Table,
TableException}
+import org.apache.flink.table.sources.{StreamTableSource, TableSource,
TableSourceFactoryService}
+
+/**
+ * Descriptor for specifying a table source in a streaming environment.
+ */
+class StreamTableSourceDescriptor(
+ tableEnv: StreamTableEnvironment,
+ schema: Schema)
+ extends TableSourceDescriptor {
+
+ schemaDescriptor = Some(schema)
+
+ /**
+ * Searches for the specified table source, configures it accordingly,
and returns it.
+ */
+ def toTableSource: TableSource[_] = {
+ val source = TableSourceFactoryService.findTableSourceFactory(this)
+ source match {
+ case _: StreamTableSource[_] => source
+ case _ => throw new TableException(
+ s"Found table source '${source.getClass.getCanonicalName}' is not
applicable " +
+ s"in a streaming environment.")
+ }
+ }
+
+ /**
+ * Searches for the specified table source, configures it accordingly,
and returns it as a table.
+ */
+ def toTable: Table = {
+ tableEnv.fromTableSource(toTableSource)
+ }
+
+ /**
+ * Searches for the specified table source, configures it accordingly,
and registers it as
+ * a table under the given name.
+ *
+ * @param name table name to be registered in the table environment
+ */
+ def register(name: String): Unit = {
+ tableEnv.registerTableSource(name, toTableSource)
+ }
+
+ /**
+ * Specifies an connector for reading data from a connector.
+ */
+ def withConnector(connector: ConnectorDescriptor):
StreamTableSourceDescriptor = {
+ connectorDescriptor = Some(connector)
+ this
+ }
+
+ /**
+ * Specifies an encoding that defines how to read data from a connector.
+ */
+ def withEncoding(encoding: EncodingDescriptor):
StreamTableSourceDescriptor = {
+ encodingDescriptor = Some(encoding)
--- End diff --
check if the connector requires an encoding?
> Create unified interfaces to configure and instatiate TableSources
> ------------------------------------------------------------------
>
> Key: FLINK-8240
> URL: https://issues.apache.org/jira/browse/FLINK-8240
> Project: Flink
> Issue Type: New Feature
> Components: Table API & SQL
> Reporter: Timo Walther
> Assignee: Timo Walther
> Priority: Major
>
> At the moment every table source has different ways for configuration and
> instantiation. Some table source are tailored to a specific encoding (e.g.,
> {{KafkaAvroTableSource}}, {{KafkaJsonTableSource}}) or only support one
> encoding for reading (e.g., {{CsvTableSource}}). Each of them might implement
> a builder or support table source converters for external catalogs.
> The table sources should have a unified interface for discovery, defining
> common properties, and instantiation. The {{TableSourceConverters}} provide a
> similar functionality but use an external catalog. We might generialize this
> interface.
> In general a table source declaration depends on the following parts:
> {code}
> - Source
> - Type (e.g. Kafka, Custom)
> - Properties (e.g. topic, connection info)
> - Encoding
> - Type (e.g. Avro, JSON, CSV)
> - Schema (e.g. Avro class, JSON field names/types)
> - Rowtime descriptor/Proctime
> - Watermark strategy and Watermark properties
> - Time attribute info
> - Bucketization
> {code}
> This issue needs a design document before implementation. Any discussion is
> very welcome.
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