org.apache.flink.cep.pattern

Class Pattern<T,F extends T>

java.lang.Object

org.apache.flink.cep.pattern.Pattern<T,F>

Type Parameters:

T - Base type of the elements appearing in the pattern

F - Subtype of T to which the current pattern operator is constrained

Direct Known Subclasses:

FollowedByPattern

public class Pattern<T,F extends T>
extends Object

Base class for a pattern definition.

A pattern definition is used by NFACompiler to create a NFA.

 Pattern<T, F> pattern = Pattern.<T>begin("start")
   .next("middle").subtype(F.class)
   .followedBy("end").where(new MyFilterFunction());
 
 

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Pattern(String name, Pattern<T,?> previous)

Method Summary

Modifier and Type	Method and Description
static <X> Pattern<X,X>	begin(String name) Starts a new pattern with the initial pattern operator whose name is provided.
FollowedByPattern<T,T>	followedBy(String name) Appends a new pattern operator to the existing one.
FilterFunction<F>	getFilterFunction()
String	getName()
Pattern<T,?>	getPrevious()
Time	getWindowTime()
Pattern<T,T>	next(String name) Appends a new pattern operator to the existing one.
<S extends F> Pattern<T,S>	subtype(Class<S> subtypeClass) Applies a subtype constraint on the current pattern operator.
Pattern<T,F>	where(FilterFunction<F> newFilterFunction) Specifies a filter condition which has to be fulfilled by an event in order to be matched.
Pattern<T,F>	within(Time windowTime) Defines the maximum time interval for a matching pattern.

Methods inherited from class java.lang.Object

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

Constructor Detail

Pattern

protected Pattern(String name,
                  Pattern<T,?> previous)

Method Detail

getName

public String getName()

getPrevious

public Pattern<T,?> getPrevious()

getFilterFunction

public FilterFunction<F> getFilterFunction()

getWindowTime

public Time getWindowTime()

where

public Pattern<T,F> where(FilterFunction<F> newFilterFunction)

Specifies a filter condition which has to be fulfilled by an event in order to be matched.

Parameters:

newFilterFunction - Filter condition

Returns:

The same pattern operator where the new filter condition is set

subtype

public <S extends F> Pattern<T,S> subtype(Class<S> subtypeClass)

Applies a subtype constraint on the current pattern operator. This means that an event has to be of the given subtype in order to be matched.

Type Parameters:

S - Type of the subtype

Parameters:

subtypeClass - Class of the subtype

Returns:

The same pattern operator with the new subtype constraint

within

public Pattern<T,F> within(Time windowTime)

Defines the maximum time interval for a matching pattern. This means that the time gap between first and the last event must not be longer than the window time.

Parameters:

windowTime - Time of the matching window

Returns:

The same pattenr operator with the new window length

next

public Pattern<T,T> next(String name)

Appends a new pattern operator to the existing one. The new pattern operator enforces strict temporal contiguity. This means that the whole pattern only matches if an event which matches this operator directly follows the preceding matching event. Thus, there cannot be any events in between two matching events.

Parameters:

name - Name of the new pattern operator

Returns:

A new pattern operator which is appended to this pattern operator

followedBy

public FollowedByPattern<T,T> followedBy(String name)

Appends a new pattern operator to the existing one. The new pattern operator enforces non-strict temporal contiguity. This means that a matching event of this operator and the preceding matching event might be interleaved with other events which are ignored.

Parameters:

name - Name of the new pattern operator

Returns:

A new pattern operator which is appended to this pattern operator

begin

public static <X> Pattern<X,X> begin(String name)

Starts a new pattern with the initial pattern operator whose name is provided. Furthermore, the base type of the event sequence is set.

Type Parameters:

X - Base type of the event pattern

Parameters:

name - Name of the new pattern operator

Returns:

The first pattern operator of a pattern