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https://issues.apache.org/jira/browse/FLINK-3708?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15249599#comment-15249599
]
ASF GitHub Bot commented on FLINK-3708:
---------------------------------------
Github user tillrohrmann commented on a diff in the pull request:
https://github.com/apache/flink/pull/1905#discussion_r60383097
--- Diff:
flink-libraries/flink-cep-scala/src/main/scala/org/apache/flink/cep/scala/pattern/Pattern.scala
---
@@ -0,0 +1,186 @@
+/*
+ * 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.cep.scala.pattern
+
+import org.apache.flink.api.common.functions.FilterFunction
+import org.apache.flink.cep
+import org.apache.flink.cep.pattern.{Pattern => JPattern}
+import org.apache.flink.streaming.api.windowing.time.Time
+
+import scala.reflect.ClassTag
+
+/**
+ * Base class for a pattern definition.
+ * <p>
+ * A pattern definition is used by { @link
org.apache.flink.cep.nfa.compiler.NFACompiler} to create
+ * a { @link NFA}.
+ *
+ * <pre>{ @code
+ * Pattern<T, F> pattern = Pattern.<T>begin("start")
+ * .next("middle").subtype(F.class)
+ * .followedBy("end").where(new MyFilterFunction());
+ * }
+ * </pre>
+ *
+ * @param jPattern Underlying Java API Pattern
+ * @tparam T Base type of the elements appearing in the pattern
+ * @tparam F Subtype of T to which the current pattern operator is
constrained
+ */
+class Pattern[T: ClassTag, F <: T : ClassTag](jPattern: JPattern[T, F]) {
+
+ private[flink] def getWrappedPattern = jPattern
+
+
+ /**
+ *
+ * @return Name of the pattern operator
+ */
+ def getName: String = jPattern.getName
+
+ /**
+ *
+ * @return Window length in which the pattern match has to occur
+ */
+ def getWindowTime: Option[Time] = {
+ val time = jPattern.getWindowTime
+ if (time == null) None else Some(time)
--- End diff --
It's easier to simply write `Option(jPattern.getWindowTime())`
> Scala API for CEP
> -----------------
>
> Key: FLINK-3708
> URL: https://issues.apache.org/jira/browse/FLINK-3708
> Project: Flink
> Issue Type: Improvement
> Components: CEP
> Affects Versions: 1.1.0
> Reporter: Till Rohrmann
> Assignee: Stefan Richter
>
> Currently, The CEP library does not support Scala case classes, because the
> {{TypeExtractor}} cannot handle them. In order to support them, it would be
> necessary to offer a Scala API for the CEP library.
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