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https://issues.apache.org/jira/browse/FLINK-6198?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16034943#comment-16034943
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ASF GitHub Bot commented on FLINK-6198:
---------------------------------------
Github user alpinegizmo commented on a diff in the pull request:
https://github.com/apache/flink/pull/4041#discussion_r119890712
--- Diff: docs/dev/libs/cep.md ---
@@ -246,63 +334,399 @@ pattern.where(event => ... /* some condition
*/).or(event => ... /* or condition
</div>
</div>
-Next, we can append further states to detect complex patterns.
-We can control the contiguity of two succeeding events to be accepted by
the pattern.
+##### Conditions on Contiguity
-Strict contiguity means that two matching events have to be directly the
one after the other.
-This means that no other events can occur in between.
-A strict contiguity pattern state can be created via the `next` method.
+FlinkCEP supports the following forms of contiguity between events:
+
+ 1. Strict Contiguity: which expects all matching events to appear
strictly the one after the other,
+ without any non-matching events in-between.
+
+ 2. Relaxed Contiguity: which simply ignores non-matching events appearing
in-between the matching ones.
+
+ 3. Non-Deterministic Relaxed Contiguity: which further relaxes contiguity
by also creating alternative
+ matches which ignore also matching events.
+
+To illustrate the above with an example, a pattern sequence `a+ b` (one or
more `a`s followed by a `b`) with
+input `a1, c, a2, b` will have the following results:
+
+ 1. Strict Contiguity: `a2 b` because there is `c` `a1` and `a2` so `a1`
is discarded.
+
+ 2. Relaxed Contiguity: `a1 b` and `a1 a2 b`, as `c` will get simply
ignored.
+
+ 3. Non-Deterministic Relaxed Contiguity: `a1 b`, `a2 b` and `a1 a2 b`.
+
+For looping states (e.g. `oneOrMore()` and `times()`) the default is
*relaxed contiguity*. If you want
+strict contiguity, you have to explicitly specify it by using the
`consecutive()` call, and if you want
+*non-deterministic relaxed contiguity* you can use the
`allowCombinations()` call.
<div class="codetabs" markdown="1">
<div data-lang="java" markdown="1">
+<table class="table table-bordered">
+ <thead>
+ <tr>
+ <th class="text-left" style="width: 25%">Pattern Operation</th>
+ <th class="text-center">Description</th>
+ </tr>
+ </thead>
+ <tbody>
+ <tr>
+ <td><strong>where(condition)</strong></td>
+ <td>
+ <p>Defines a condition for the current state. Only if an
event satisifes the condition,
+ it can match the state. Multiple consecutive where()
clauses lead to their condtions being
+ ANDed:</p>
+{% highlight java %}
+patternState.where(new IterativeCondition<Event>() {
+ @Override
+ public boolean filter(Event value, Context ctx) throws Exception {
+ return ... // some condition
+ }
+});
+{% endhighlight %}
+ </td>
+ </tr>
+ <tr>
+ <td><strong>or(condition)</strong></td>
+ <td>
+ <p>Adds a new condition which is ORed with an existing
one. Only if an event passes one of the
+ conditions, it can match the state:</p>
--- End diff --
An event can match the state only if it passes at least one of the
conditions.
> Update the documentation of the CEP library to include all the new features.
> ----------------------------------------------------------------------------
>
> Key: FLINK-6198
> URL: https://issues.apache.org/jira/browse/FLINK-6198
> Project: Flink
> Issue Type: Sub-task
> Components: CEP
> Affects Versions: 1.3.0
> Reporter: Kostas Kloudas
> Assignee: Kostas Kloudas
> Priority: Critical
> Fix For: 1.3.0
>
>
> New features to include:
> * Iterative Functions
> * Quantifiers
> * Time handling
> * Migration from FilterFunction to IterativeCondition
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