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https://issues.apache.org/jira/browse/FLINK-5571?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15867771#comment-15867771
]
ASF GitHub Bot commented on FLINK-5571:
---------------------------------------
Github user twalthr commented on a diff in the pull request:
https://github.com/apache/flink/pull/3176#discussion_r101265088
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/functions/UDFContext.scala
---
@@ -0,0 +1,53 @@
+/*
+ * 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.functions
+
+import java.io.File
+
+import org.apache.flink.annotation.PublicEvolving
+import org.apache.flink.api.common.functions.RuntimeContext
+import org.apache.flink.metrics.MetricGroup
+
+class UDFContext(context: RuntimeContext) {
+
+ /**
+ * Returns the metric group for this parallel subtask.
+ */
+ @PublicEvolving
+ def getMetricGroup: MetricGroup = context.getMetricGroup
+
+ /**
+ * Get the local temporary file copies of distributed cache files
--- End diff --
Please also add Javadoc for parameters and return values. This user-facing
API and should be well documented. Please also add some website documentation.
> add open and close methods for UserDefinedFunction in TableAPI & SQL
> --------------------------------------------------------------------
>
> Key: FLINK-5571
> URL: https://issues.apache.org/jira/browse/FLINK-5571
> Project: Flink
> Issue Type: New Feature
> Components: Table API & SQL
> Reporter: godfrey he
> Assignee: godfrey he
>
> Currently, a User Defined Function (UDF) in table API & SQL works on zero,
> one, or multiple values in custom evaluation method. Many UDFs need more
> complex features, e.g. report metrics, get parameters from job configuration,
> or get extra data from distribute cache file, etc. Adding open and close
> methods in UserDefinedFunction class can solve this problem. The code cloud
> look like:
> {code}
> trait UserDefinedFunction {
> def open(context: UDFContext): Unit = {}
> def close(): Unit = {}
> }
> {code}
> UDFContext contains the information about metric reporters, job parameters,
> distribute cache, etc. The code cloud look like:
> {code}
> class UDFContext(context: RuntimeContext) {
> def getMetricGroup: MetricGroup = ???
> def getDistributedCacheFile(name: String): File = ???
> def getJobParameter(key: String, default: String): String = ???
> }
> {code}
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