org.apache.flink.datastream.api.function

接口 ProcessFunction

所有超级接口:

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

所有已知子接口:

OneInputStreamProcessFunction<IN,OUT>, TwoInputBroadcastStreamProcessFunction<IN1,IN2,OUT>, TwoInputNonBroadcastStreamProcessFunction<IN1,IN2,OUT>, TwoOutputStreamProcessFunction<IN,OUT1,OUT2>

@Experimental
public interface ProcessFunction
extends org.apache.flink.api.common.functions.Function

Base class for all user defined process functions.

方法概要

限定符和类型	方法和说明
default void	close() Tear-down method for the user code.
default void	open() Initialization method for the function.
default Set<org.apache.flink.api.common.state.StateDeclaration>	usesStates() Explicitly declares states upfront.

方法详细资料

open

default void open()
           throws Exception

Initialization method for the function. It is called before the actual working methods (like processRecord) and thus suitable for one time setup work.

By default, this method does nothing.

抛出:

Exception - Implementations may forward exceptions, which are caught by the runtime. When the runtime catches an exception, it aborts the task and lets the fail-over logic decide whether to retry the task execution.

usesStates

default Set<org.apache.flink.api.common.state.StateDeclaration> usesStates()

Explicitly declares states upfront. Each specific state must be declared in this method before it can be used.

返回:

all declared states used by this process function.

close

default void close()
            throws Exception

Tear-down method for the user code. It is called after the last call to the main working methods (e.g. processRecord).

This method can be used for clean up work.

抛出:

Exception - Implementations may forward exceptions, which are caught by the runtime. When the runtime catches an exception, it aborts the task and lets the fail-over logic decide whether to retry the task execution.