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https://issues.apache.org/jira/browse/FLINK-8240?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16334936#comment-16334936
]
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_r163007563
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/descriptors/JSON.scala
---
@@ -0,0 +1,140 @@
+/*
+ * 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 java.util
+
+import org.apache.flink.api.common.typeinfo.TypeInformation
+import org.apache.flink.table.api.TableSchema
+
+import scala.collection.mutable
+import scala.collection.JavaConverters._
+
+/**
+ * Encoding descriptor for JSON.
+ */
+class JSON extends EncodingDescriptor("json") {
+
+ private val encodingSchema: mutable.LinkedHashMap[String, String] =
+ mutable.LinkedHashMap[String, String]()
+ private var fieldMapping: Option[util.Map[String, String]] = None
+ private var failOnMissingField: Option[Boolean] = None
+
+ /**
+ * Sets the JSON schema with field names and the types for the
JSON-encoded input.
+ * The JSON schema must not contain nested fields.
+ *
+ * This method overwrites existing fields added with [[field()]].
+ *
+ * @param schema the table schema
+ */
+ def schema(schema: TableSchema): JSON = {
+ this.encodingSchema.clear()
+ NormalizedProperties.normalizeTableSchema(schema).foreach {
+ case (n, t) => field(n, t)
+ }
+ this
+ }
+
+ /**
+ * Adds a JSON field with the field name and the type information for
the JSON-encoding.
+ * This method can be called multiple times. The call order of this
method defines
+ * also the order of the fields in the JSON-encoding.
+ *
+ * @param fieldName the field name
+ * @param fieldType the type information of the field
+ */
+ def field(fieldName: String, fieldType: TypeInformation[_]): JSON = {
+ field(fieldName, NormalizedProperties.normalizeTypeInfo(fieldType))
+ this
+ }
+
+ /**
+ * Adds a JSON field with the field name and the type string for the
JSON-encoding.
+ * This method can be called multiple times. The call order of this
method defines
+ * also the order of the fields in the JSON-encoding.
+ *
+ * @param fieldName the field name
+ * @param fieldType the type string of the field
+ */
+ def field(fieldName: String, fieldType: String): JSON = {
+ if (encodingSchema.contains(fieldName)) {
+ throw new IllegalArgumentException(s"Duplicate field name
$fieldName.")
+ }
+ encodingSchema += (fieldName -> fieldType)
+ this
+ }
+
+ /**
+ * Sets a mapping from schema fields to fields of the JSON schema.
+ *
+ * A field mapping is required if the fields of produced tables should
be named different than
+ * the fields of the JSON records.
+ * The key of the provided Map refers to the field of the table schema,
+ * the value to the field in the JSON schema.
+ *
+ * @param tableToJsonMapping A mapping from table schema fields to JSON
schema fields.
+ * @return The builder.
+ */
+ def tableToJsonMapping(tableToJsonMapping: util.Map[String, String]):
JSON = {
+ this.fieldMapping = Some(tableToJsonMapping)
+ this
+ }
+
+ /**
+ * Sets flag whether to fail if a field is missing or not.
+ *
+ * @param failOnMissingField If set to true, the operation fails if
there is a missing field.
+ * If set to false, a missing field is set to
null.
+ * @return The builder.
+ */
+ def failOnMissingField(failOnMissingField: Boolean): JSON = {
+ this.failOnMissingField = Some(failOnMissingField)
+ this
+ }
+
+ /**
+ * Internal method for encoding properties conversion.
+ */
+ override protected def addEncodingProperties(properties:
NormalizedProperties): Unit = {
+ properties.putIndexedFixedProperties(
--- End diff --
We should add properties with support for nested fields
> 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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