org.apache.flink.cep.pattern.conditions

Class SimpleCondition<T>

java.lang.Object

org.apache.flink.cep.pattern.conditions.IterativeCondition<T>

org.apache.flink.cep.pattern.conditions.SimpleCondition<T>

All Implemented Interfaces:

Serializable, org.apache.flink.api.common.functions.FilterFunction<T>, org.apache.flink.api.common.functions.Function

Direct Known Subclasses:

SubtypeCondition

@Internal
public abstract class SimpleCondition<T>
extends IterativeCondition<T>
implements org.apache.flink.api.common.functions.FilterFunction<T>

A user-defined condition that decides if an element should be accepted in the pattern or not. Accepting an element also signals a state transition for the corresponding NFA.

Contrary to the IterativeCondition, conditions that extend this class do not have access to the previously accepted elements in the pattern. Conditions that extend this class are simple filter(...) functions that decide based on the properties of the element at hand.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.flink.cep.pattern.conditions.IterativeCondition

IterativeCondition.Context<T>

Constructor Summary

Constructors

Constructor and Description
SimpleCondition()

Method Summary

Modifier and Type	Method and Description
boolean	filter(T value, IterativeCondition.Context<T> ctx) The filter function that evaluates the predicate.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.flink.api.common.functions.FilterFunction

filter

Constructor Detail

SimpleCondition

public SimpleCondition()

Method Detail

filter

public boolean filter(T value,
                      IterativeCondition.Context<T> ctx)
               throws Exception

Description copied from class: IterativeCondition

The filter function that evaluates the predicate.

IMPORTANT: The system assumes that the function does not modify the elements on which the predicate is applied. Violating this assumption can lead to incorrect results.

Specified by:

filter in class IterativeCondition<T>

Parameters:

value - The value to be tested.

ctx - The IterativeCondition.Context used for the evaluation of the function and provides access to the already accepted events in the pattern (see IterativeCondition.Context.getEventsForPattern(String)).

Returns:

true for values that should be retained, false for values to be filtered out.

Throws:

Exception - This method may throw exceptions. Throwing an exception will cause the operation to fail and may trigger recovery.