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https://issues.apache.org/jira/browse/FLINK-10417?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16633679#comment-16633679
]
ASF GitHub Bot commented on FLINK-10417:
----------------------------------------
dawidwys closed pull request #6758: [FLINK-10417][cep] Added option to throw
exception on pattern variable mis…
URL: https://github.com/apache/flink/pull/6758
This is a PR merged from a forked repository.
As GitHub hides the original diff on merge, it is displayed below for
the sake of provenance:
As this is a foreign pull request (from a fork), the diff is supplied
below (as it won't show otherwise due to GitHub magic):
diff --git a/docs/dev/libs/cep.md b/docs/dev/libs/cep.md
index ad321bf71b5..d7f915fc62e 100644
--- a/docs/dev/libs/cep.md
+++ b/docs/dev/libs/cep.md
@@ -1385,6 +1385,23 @@ Pattern.begin("patternName", skipStrategy)
</div>
</div>
+{% warn Attention %} For SKIP_TO_FIRST/LAST there are two options how to
handle cases when there are no elements mapped to
+the specified variable. By default a NO_SKIP strategy will be used in this
case. The other option is to throw exception in such situation.
+One can enable this option by:
+
+<div class="codetabs" markdown="1">
+<div data-lang="java" markdown="1">
+{% highlight java %}
+AfterMatchSkipStrategy.skipToFirst(patternName).throwExceptionOnMiss()
+{% endhighlight %}
+</div>
+<div data-lang="scala" markdown="1">
+{% highlight scala %}
+AfterMatchSkipStrategy.skipToFirst(patternName).throwExceptionOnMiss()
+{% endhighlight %}
+</div>
+</div>
+
## Detecting Patterns
After specifying the pattern sequence you are looking for, it is time to apply
it to your input stream to detect
diff --git
a/flink-libraries/flink-cep/src/main/java/org/apache/flink/cep/nfa/aftermatch/AfterMatchSkipStrategy.java
b/flink-libraries/flink-cep/src/main/java/org/apache/flink/cep/nfa/aftermatch/AfterMatchSkipStrategy.java
index 8151a124af4..f4448a35560 100644
---
a/flink-libraries/flink-cep/src/main/java/org/apache/flink/cep/nfa/aftermatch/AfterMatchSkipStrategy.java
+++
b/flink-libraries/flink-cep/src/main/java/org/apache/flink/cep/nfa/aftermatch/AfterMatchSkipStrategy.java
@@ -43,8 +43,8 @@
* @param patternName the pattern name to skip to
* @return the created AfterMatchSkipStrategy
*/
- public static AfterMatchSkipStrategy skipToFirst(String patternName) {
- return new SkipToFirstStrategy(patternName);
+ public static SkipToFirstStrategy skipToFirst(String patternName) {
+ return new SkipToFirstStrategy(patternName, false);
}
/**
@@ -53,8 +53,8 @@ public static AfterMatchSkipStrategy skipToFirst(String
patternName) {
* @param patternName the pattern name to skip to
* @return the created AfterMatchSkipStrategy
*/
- public static AfterMatchSkipStrategy skipToLast(String patternName) {
- return new SkipToLastStrategy(patternName);
+ public static SkipToLastStrategy skipToLast(String patternName) {
+ return new SkipToLastStrategy(patternName, false);
}
/**
@@ -62,7 +62,7 @@ public static AfterMatchSkipStrategy skipToLast(String
patternName) {
*
* @return the created AfterMatchSkipStrategy
*/
- public static AfterMatchSkipStrategy skipPastLastEvent() {
+ public static SkipPastLastStrategy skipPastLastEvent() {
return SkipPastLastStrategy.INSTANCE;
}
@@ -71,7 +71,7 @@ public static AfterMatchSkipStrategy skipPastLastEvent() {
*
* @return the created AfterMatchSkipStrategy
*/
- public static AfterMatchSkipStrategy noSkip() {
+ public static NoSkipStrategy noSkip() {
return NoSkipStrategy.INSTANCE;
}
diff --git
a/flink-libraries/flink-cep/src/main/java/org/apache/flink/cep/nfa/aftermatch/SkipToElementStrategy.java
b/flink-libraries/flink-cep/src/main/java/org/apache/flink/cep/nfa/aftermatch/SkipToElementStrategy.java
new file mode 100644
index 00000000000..5554151ccbd
--- /dev/null
+++
b/flink-libraries/flink-cep/src/main/java/org/apache/flink/cep/nfa/aftermatch/SkipToElementStrategy.java
@@ -0,0 +1,89 @@
+/*
+ * 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.nfa.aftermatch;
+
+import org.apache.flink.cep.nfa.sharedbuffer.EventId;
+import org.apache.flink.util.FlinkRuntimeException;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+
+import static org.apache.flink.util.Preconditions.checkNotNull;
+
+abstract class SkipToElementStrategy extends AfterMatchSkipStrategy {
+ private static final long serialVersionUID = 7127107527654629026L;
+ private final String patternName;
+ private final boolean shouldThrowException;
+
+ SkipToElementStrategy(String patternName, boolean shouldThrowException)
{
+ this.patternName = checkNotNull(patternName);
+ this.shouldThrowException = shouldThrowException;
+ }
+
+ @Override
+ public boolean isSkipStrategy() {
+ return true;
+ }
+
+ @Override
+ protected boolean shouldPrune(EventId startEventID, EventId pruningId) {
+ return startEventID != null &&
startEventID.compareTo(pruningId) < 0;
+ }
+
+ @Override
+ protected EventId getPruningId(Collection<Map<String, List<EventId>>>
match) {
+ EventId pruningId = null;
+ for (Map<String, List<EventId>> resultMap : match) {
+ List<EventId> pruningPattern =
resultMap.get(patternName);
+ if (pruningPattern == null || pruningPattern.isEmpty())
{
+ if (shouldThrowException) {
+ throw new
FlinkRuntimeException(String.format(
+ "Could not skip to %s. No such
element in the found match %s",
+ patternName,
+ resultMap));
+ }
+ } else {
+ pruningId = max(pruningId,
pruningPattern.get(getIndex(pruningPattern.size())));
+ }
+ }
+
+ return pruningId;
+ }
+
+ @Override
+ public Optional<String> getPatternName() {
+ return Optional.of(patternName);
+ }
+
+ /**
+ * Tells which element from the list of events mapped to *PatternName*
to use.
+ *
+ * @param size number of elements mapped to the *PatternName*
+ * @return index of event mapped to *PatternName* to use for pruning
+ */
+ abstract int getIndex(int size);
+
+ /**
+ * Enables throwing exception if no events mapped to the *PatternName*.
If not enabled and no events were mapped,
+ * {@link NoSkipStrategy} will be used
+ */
+ public abstract SkipToElementStrategy throwExceptionOnMiss();
+}
diff --git
a/flink-libraries/flink-cep/src/main/java/org/apache/flink/cep/nfa/aftermatch/SkipToFirstStrategy.java
b/flink-libraries/flink-cep/src/main/java/org/apache/flink/cep/nfa/aftermatch/SkipToFirstStrategy.java
index 7d7be4a4b1e..e8befebe5fc 100644
---
a/flink-libraries/flink-cep/src/main/java/org/apache/flink/cep/nfa/aftermatch/SkipToFirstStrategy.java
+++
b/flink-libraries/flink-cep/src/main/java/org/apache/flink/cep/nfa/aftermatch/SkipToFirstStrategy.java
@@ -18,59 +18,30 @@
package org.apache.flink.cep.nfa.aftermatch;
-import org.apache.flink.cep.nfa.sharedbuffer.EventId;
-
-import java.util.Collection;
-import java.util.List;
-import java.util.Map;
-import java.util.Optional;
-
-import static org.apache.flink.util.Preconditions.checkNotNull;
-
/**
* Discards every partial match that contains event of the match preceding the
first of *PatternName*.
*/
-public class SkipToFirstStrategy extends AfterMatchSkipStrategy {
-
+public final class SkipToFirstStrategy extends SkipToElementStrategy {
private static final long serialVersionUID = 7127107527654629026L;
- private final String patternName;
- SkipToFirstStrategy(String patternName) {
- this.patternName = checkNotNull(patternName);
+ SkipToFirstStrategy(String patternName, boolean shouldThrowException) {
+ super(patternName, shouldThrowException);
}
@Override
- public boolean isSkipStrategy() {
- return true;
- }
-
- @Override
- protected boolean shouldPrune(EventId startEventID, EventId pruningId) {
- return startEventID != null &&
startEventID.compareTo(pruningId) < 0;
- }
-
- @Override
- protected EventId getPruningId(Collection<Map<String, List<EventId>>>
match) {
- EventId pruniningId = null;
- for (Map<String, List<EventId>> resultMap : match) {
- List<EventId> pruningPattern =
resultMap.get(patternName);
- if (pruningPattern != null &&
!pruningPattern.isEmpty()) {
- pruniningId = max(pruniningId,
pruningPattern.get(0));
- }
- }
-
- return pruniningId;
+ public SkipToElementStrategy throwExceptionOnMiss() {
+ return new SkipToFirstStrategy(getPatternName().get(), true);
}
@Override
- public Optional<String> getPatternName() {
- return Optional.of(patternName);
+ int getIndex(int size) {
+ return 0;
}
@Override
public String toString() {
return "SkipToFirstStrategy{" +
- "patternName='" + patternName + '\'' +
+ "patternName='" + getPatternName().get() + '\'' +
'}';
}
}
diff --git
a/flink-libraries/flink-cep/src/main/java/org/apache/flink/cep/nfa/aftermatch/SkipToLastStrategy.java
b/flink-libraries/flink-cep/src/main/java/org/apache/flink/cep/nfa/aftermatch/SkipToLastStrategy.java
index 0f6c3eddcfb..3c33bd13f62 100644
---
a/flink-libraries/flink-cep/src/main/java/org/apache/flink/cep/nfa/aftermatch/SkipToLastStrategy.java
+++
b/flink-libraries/flink-cep/src/main/java/org/apache/flink/cep/nfa/aftermatch/SkipToLastStrategy.java
@@ -18,59 +18,30 @@
package org.apache.flink.cep.nfa.aftermatch;
-import org.apache.flink.cep.nfa.sharedbuffer.EventId;
-
-import java.util.Collection;
-import java.util.List;
-import java.util.Map;
-import java.util.Optional;
-
-import static org.apache.flink.util.Preconditions.checkNotNull;
-
/**
* Discards every partial match that contains event of the match preceding the
last of *PatternName*.
*/
-public class SkipToLastStrategy extends AfterMatchSkipStrategy {
+public final class SkipToLastStrategy extends SkipToElementStrategy {
private static final long serialVersionUID = 7585116990619594531L;
- private final String patternName;
- SkipToLastStrategy(String patternName) {
- this.patternName = checkNotNull(patternName);
- }
-
- @Override
- public boolean isSkipStrategy() {
- return true;
+ SkipToLastStrategy(String patternName, boolean shouldThrowException) {
+ super(patternName, shouldThrowException);
}
@Override
- protected boolean shouldPrune(EventId startEventID, EventId pruningId) {
- return startEventID != null &&
startEventID.compareTo(pruningId) < 0;
- }
-
- @Override
- protected EventId getPruningId(Collection<Map<String, List<EventId>>>
match) {
- EventId pruningId = null;
- for (Map<String, List<EventId>> resultMap : match) {
- List<EventId> pruningPattern =
resultMap.get(patternName);
-
- if (pruningPattern != null &&
!pruningPattern.isEmpty()) {
- pruningId = max(pruningId,
pruningPattern.get(pruningPattern.size() - 1));
- }
- }
-
- return pruningId;
+ public SkipToElementStrategy throwExceptionOnMiss() {
+ return new SkipToLastStrategy(getPatternName().get(), true);
}
@Override
- public Optional<String> getPatternName() {
- return Optional.of(patternName);
+ int getIndex(int size) {
+ return size - 1;
}
@Override
public String toString() {
return "SkipToLastStrategy{" +
- "patternName='" + patternName + '\'' +
+ "patternName='" + getPatternName().get() + '\'' +
'}';
}
}
diff --git
a/flink-libraries/flink-cep/src/test/java/org/apache/flink/cep/nfa/AfterMatchSkipITCase.java
b/flink-libraries/flink-cep/src/test/java/org/apache/flink/cep/nfa/AfterMatchSkipITCase.java
index 4462d103164..6681090d8b2 100644
---
a/flink-libraries/flink-cep/src/test/java/org/apache/flink/cep/nfa/AfterMatchSkipITCase.java
+++
b/flink-libraries/flink-cep/src/test/java/org/apache/flink/cep/nfa/AfterMatchSkipITCase.java
@@ -24,6 +24,7 @@
import org.apache.flink.cep.pattern.conditions.IterativeCondition;
import org.apache.flink.cep.pattern.conditions.SimpleCondition;
import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
+import org.apache.flink.util.FlinkRuntimeException;
import org.apache.flink.util.TestLogger;
import org.apache.flink.shaded.guava18.com.google.common.collect.Lists;
@@ -432,6 +433,74 @@ public boolean filter(Event value) throws Exception {
));
}
+ @Test(expected = FlinkRuntimeException.class)
+ public void testSkipToFirstNonExistentPosition() throws Exception {
+
MissedSkipTo.compute(AfterMatchSkipStrategy.skipToFirst("b").throwExceptionOnMiss());
+
+ //exception should be thrown
+ }
+
+ @Test
+ public void testSkipToFirstNonExistentPositionWithoutException() throws
Exception {
+ List<List<Event>> resultingPatterns =
MissedSkipTo.compute(AfterMatchSkipStrategy.skipToFirst("b"));
+
+ compareMaps(resultingPatterns, Collections.singletonList(
+ Lists.newArrayList(MissedSkipTo.a, MissedSkipTo.c)
+ ));
+ }
+
+ @Test(expected = FlinkRuntimeException.class)
+ public void testSkipToLastNonExistentPosition() throws Exception {
+
MissedSkipTo.compute(AfterMatchSkipStrategy.skipToLast("b").throwExceptionOnMiss());
+
+ //exception should be thrown
+ }
+
+ @Test
+ public void testSkipToLastNonExistentPositionWithoutException() throws
Exception {
+ List<List<Event>> resultingPatterns =
MissedSkipTo.compute(AfterMatchSkipStrategy.skipToFirst("b"));
+
+ compareMaps(resultingPatterns, Collections.singletonList(
+ Lists.newArrayList(MissedSkipTo.a, MissedSkipTo.c)
+ ));
+ }
+
+ static class MissedSkipTo {
+ static Event a = new Event(1, "a", 0.0);
+ static Event c = new Event(4, "c", 0.0);
+
+ static List<List<Event>> compute(AfterMatchSkipStrategy
skipStrategy) throws Exception {
+ List<StreamRecord<Event>> streamEvents = new
ArrayList<>();
+
+ streamEvents.add(new StreamRecord<>(a));
+ streamEvents.add(new StreamRecord<>(c));
+
+ Pattern<Event, ?> pattern =
Pattern.<Event>begin("a").where(
+ new SimpleCondition<Event>() {
+
+ @Override
+ public boolean filter(Event value)
throws Exception {
+ return
value.getName().contains("a");
+ }
+ }
+ ).next("b").where(new SimpleCondition<Event>() {
+ @Override
+ public boolean filter(Event value) throws
Exception {
+ return value.getName().contains("b");
+ }
+ }).oneOrMore().optional().consecutive()
+ .next("c").where(new SimpleCondition<Event>() {
+ @Override
+ public boolean filter(Event value)
throws Exception {
+ return
value.getName().contains("c");
+ }
+ });
+ NFA<Event> nfa = compile(pattern, false);
+
+ return feedNFA(streamEvents, nfa, skipStrategy);
+ }
+ }
+
@Test
public void testSkipToLastWithOneOrMore() throws Exception {
List<StreamRecord<Event>> streamEvents = new ArrayList<>();
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> Add option to throw exception on pattern variable miss with SKIP_TO_FIRST/LAST
> ------------------------------------------------------------------------------
>
> Key: FLINK-10417
> URL: https://issues.apache.org/jira/browse/FLINK-10417
> Project: Flink
> Issue Type: Improvement
> Components: CEP
> Reporter: Dawid Wysakowicz
> Assignee: Dawid Wysakowicz
> Priority: Major
> Labels: pull-request-available
> Fix For: 1.7.0
>
>
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