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https://issues.apache.org/jira/browse/FLINK-3319?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15340352#comment-15340352
]
Robert Thorman commented on FLINK-3319:
---------------------------------------
Below is a test case I wrote which passes with a new OrFilterFunction. Let me
know if this is what was expected or not.
/**
* Checks that a certain event sequence is recognized with an OR filter
* @throws Exception
*/
@Test
public void testSimpleOrFilterPatternCEP() throws Exception {
StreamExecutionEnvironment env =
StreamExecutionEnvironment.getExecutionEnvironment();
DataStream<Event> input = env.fromElements(
new Event(1, "start", 1.0),
new Event(2, "middle", 2.0),
new Event(3, "end", 3.0),
new Event(4, "start", 4.0),
new Event(5, "middle", 5.0),
new Event(6, "end", 6.0)
);
Pattern<Event, ?> pattern = Pattern.<Event>begin("start")
.where(new FilterFunction<Event>() {
@Override
public boolean filter(Event value)
throws Exception {
return
value.getName().equals("start");
}
})
.followedBy("middle")
.where(new FilterFunction<Event>() {
@Override
public boolean filter(Event value)
throws Exception {
return value.getPrice() == 2.0;
}
})
.or(new FilterFunction<Event>() {
@Override
public boolean filter(Event value)
throws Exception {
return value.getPrice() == 5.0;
}
})
.followedBy("end").where(new
FilterFunction<Event>() {
@Override
public boolean filter(Event value)
throws Exception {
return
value.getName().equals("end");
}
});
DataStream<String> result = CEP.pattern(input,
pattern).select(new PatternSelectFunction<Event, String>() {
@Override
public String select(Map<String, Event> pattern) {
StringBuilder builder = new StringBuilder();
builder.append(pattern.get("start").getId()).append(",")
.append(pattern.get("middle").getId()).append(",")
.append(pattern.get("end").getId());
return builder.toString();
}
});
result.writeAsText(resultPath, FileSystem.WriteMode.OVERWRITE);
// expected sequence of matching event ids
expected = "1,5,6\n1,2,3\n4,5,6\n1,2,6";
env.execute();
}
> Add or operator to CEP's pattern API
> ------------------------------------
>
> Key: FLINK-3319
> URL: https://issues.apache.org/jira/browse/FLINK-3319
> Project: Flink
> Issue Type: Improvement
> Components: CEP
> Affects Versions: 1.0.0
> Reporter: Till Rohrmann
> Assignee: Robert Thorman
> Priority: Minor
>
> Adding an {{or}} operator to CEP's pattern API would be beneficial. This
> would considerably extend the set of supported patterns. The {{or}} operator
> lets you define multiple succeeding pattern states for the next stage.
> {code}
> Pattern.begin("start").next("middle1").where(...).or("middle2").where(...)
> {code}
> In order to implement the {{or}} operator, one has to extend the {{Pattern}}
> class. Furthermore, the {{NFACompiler}} has to be extended to generate two
> resulting pattern states in case of an {{or}} operator.
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