org.apache.flink.streaming.api.functions

类 ProcessFunction<I,O>

java.lang.Object

org.apache.flink.api.common.functions.AbstractRichFunction

org.apache.flink.streaming.api.functions.ProcessFunction<I,O>

类型参数:

I - Type of the input elements.

O - Type of the output elements.

所有已实现的接口:

Serializable, org.apache.flink.api.common.functions.Function, org.apache.flink.api.common.functions.RichFunction

@PublicEvolving
public abstract class ProcessFunction<I,O>
extends org.apache.flink.api.common.functions.AbstractRichFunction

A function that processes elements of a stream.

For every element in the input stream processElement(Object, Context, Collector) is invoked. This can produce zero or more elements as output. Implementations can also query the time and set timers through the provided ProcessFunction.Context. For firing timers onTimer(long, OnTimerContext, Collector) will be invoked. This can again produce zero or more elements as output and register further timers.

NOTE: Access to keyed state and timers (which are also scoped to a key) is only available if the ProcessFunction is applied on a KeyedStream.

NOTE: A ProcessFunction is always a RichFunction. Therefore, access to the RuntimeContext is always available and setup and teardown methods can be implemented. See RichFunction.open(org.apache.flink.configuration.Configuration) and RichFunction.close().

另请参阅:

序列化表格

嵌套类概要

嵌套类

限定符和类型	类和说明
class	ProcessFunction.Context Information available in an invocation of processElement(Object, Context, Collector) or onTimer(long, OnTimerContext, Collector).
class	ProcessFunction.OnTimerContext Information available in an invocation of onTimer(long, OnTimerContext, Collector).

构造器概要

构造器

构造器和说明
ProcessFunction()

方法概要

限定符和类型	方法和说明
void	onTimer(long timestamp, ProcessFunction.OnTimerContext ctx, org.apache.flink.util.Collector<O> out) Called when a timer set using TimerService fires.
abstract void	processElement(I value, ProcessFunction.Context ctx, org.apache.flink.util.Collector<O> out) Process one element from the input stream.

从类继承的方法 org.apache.flink.api.common.functions.AbstractRichFunction

close, getIterationRuntimeContext, getRuntimeContext, open, setRuntimeContext

从类继承的方法 java.lang.Object

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

构造器详细资料

ProcessFunction

public ProcessFunction()

方法详细资料

processElement

public abstract void processElement(I value,
                                    ProcessFunction.Context ctx,
                                    org.apache.flink.util.Collector<O> out)
                             throws Exception

Process one element from the input stream.

This function can output zero or more elements using the Collector parameter and also update internal state or set timers using the ProcessFunction.Context parameter.

参数:

value - The input value.

ctx - A ProcessFunction.Context that allows querying the timestamp of the element and getting a TimerService for registering timers and querying the time. The context is only valid during the invocation of this method, do not store it.

out - The collector for returning result values.

抛出:

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

onTimer

public void onTimer(long timestamp,
                    ProcessFunction.OnTimerContext ctx,
                    org.apache.flink.util.Collector<O> out)
             throws Exception

Called when a timer set using TimerService fires.

参数:

timestamp - The timestamp of the firing timer.

ctx - An ProcessFunction.OnTimerContext that allows querying the timestamp of the firing timer, querying the TimeDomain of the firing timer and getting a TimerService for registering timers and querying the time. The context is only valid during the invocation of this method, do not store it.

out - The collector for returning result values.

抛出:

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