org.apache.flink.streaming.api.functions.source.datagen

类 DataGeneratorSource<T>

java.lang.Object

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

org.apache.flink.streaming.api.functions.source.RichParallelSourceFunction<T>

org.apache.flink.streaming.api.functions.source.datagen.DataGeneratorSource<T>

所有已实现的接口:

Serializable, org.apache.flink.api.common.functions.Function, org.apache.flink.api.common.functions.RichFunction, CheckpointedFunction, ParallelSourceFunction<T>, SourceFunction<T>

@Experimental
public class DataGeneratorSource<T>
extends RichParallelSourceFunction<T>
implements CheckpointedFunction

A data generator source that abstract data generator. It can be used to easy startup/test for streaming job and performance testing. It is stateful, re-scalable, possibly in parallel.

另请参阅:

序列化表格

嵌套类概要

从接口继承的嵌套类/接口 org.apache.flink.streaming.api.functions.source.SourceFunction

SourceFunction.SourceContext<T>

构造器概要

构造器

构造器和说明
DataGeneratorSource(DataGenerator<T> generator) Creates a source that emits records by DataGenerator without controlling emit rate.
DataGeneratorSource(DataGenerator<T> generator, long rowsPerSecond, Long numberOfRows) Creates a source that emits records by DataGenerator.

方法概要

限定符和类型	方法和说明
void	cancel() Cancels the source.
void	close()
void	initializeState(org.apache.flink.runtime.state.FunctionInitializationContext context) This method is called when the parallel function instance is created during distributed execution.
void	open(org.apache.flink.configuration.Configuration parameters)
void	run(SourceFunction.SourceContext<T> ctx) Starts the source.
void	snapshotState(org.apache.flink.runtime.state.FunctionSnapshotContext context) This method is called when a snapshot for a checkpoint is requested.

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

getIterationRuntimeContext, getRuntimeContext, 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

DataGeneratorSource

public DataGeneratorSource(DataGenerator<T> generator)

Creates a source that emits records by DataGenerator without controlling emit rate.

参数:

generator - data generator.

DataGeneratorSource

public DataGeneratorSource(DataGenerator<T> generator,
                           long rowsPerSecond,
                           @Nullable
                           Long numberOfRows)

Creates a source that emits records by DataGenerator.

参数:

generator - data generator.

rowsPerSecond - Control the emit rate.

numberOfRows - Total number of rows to output.

方法详细资料

open

public void open(org.apache.flink.configuration.Configuration parameters)
          throws Exception

指定者:

open 在接口中 org.apache.flink.api.common.functions.RichFunction

覆盖:

open 在类中 org.apache.flink.api.common.functions.AbstractRichFunction

抛出:

Exception

initializeState

public void initializeState(org.apache.flink.runtime.state.FunctionInitializationContext context)
                     throws Exception

从接口复制的说明: CheckpointedFunction

This method is called when the parallel function instance is created during distributed execution. Functions typically set up their state storing data structures in this method.

指定者:

initializeState 在接口中 CheckpointedFunction

参数:

context - the context for initializing the operator

抛出:

Exception - Thrown, if state could not be created ot restored.

snapshotState

public void snapshotState(org.apache.flink.runtime.state.FunctionSnapshotContext context)
                   throws Exception

从接口复制的说明: CheckpointedFunction

This method is called when a snapshot for a checkpoint is requested. This acts as a hook to the function to ensure that all state is exposed by means previously offered through FunctionInitializationContext when the Function was initialized, or offered now by FunctionSnapshotContext itself.

指定者:

snapshotState 在接口中 CheckpointedFunction

参数:

context - the context for drawing a snapshot of the operator

抛出:

Exception - Thrown, if state could not be created ot restored.

run

public void run(SourceFunction.SourceContext<T> ctx)
         throws Exception

从接口复制的说明: SourceFunction

Starts the source. Implementations use the SourceFunction.SourceContext to emit elements. Sources that checkpoint their state for fault tolerance should use the SourceFunction.SourceContext.getCheckpointLock() checkpoint lock} to ensure consistency between the bookkeeping and emitting the elements.

Sources that implement CheckpointedFunction must lock on the SourceFunction.SourceContext.getCheckpointLock() checkpoint lock} checkpoint lock (using a synchronized block) before updating internal state and emitting elements, to make both an atomic operation.

Refer to the top-level class docs for an example.

指定者:

run 在接口中 SourceFunction<T>

参数:

ctx - The context to emit elements to and for accessing locks.

抛出:

Exception

close

public void close()
           throws Exception

指定者:

close 在接口中 org.apache.flink.api.common.functions.RichFunction

覆盖:

close 在类中 org.apache.flink.api.common.functions.AbstractRichFunction

抛出:

Exception

cancel

public void cancel()

从接口复制的说明: SourceFunction

Cancels the source. Most sources will have a while loop inside the SourceFunction.run(SourceContext) method. The implementation needs to ensure that the source will break out of that loop after this method is called.

A typical pattern is to have an "volatile boolean isRunning" flag that is set to false in this method. That flag is checked in the loop condition.

In case of an ungraceful shutdown (cancellation of the source operator, possibly for failover), the thread that calls SourceFunction.run(SourceContext) will also be interrupted) by the Flink runtime, in order to speed up the cancellation (to ensure threads exit blocking methods fast, like I/O, blocking queues, etc.). The interruption happens strictly after this method has been called, so any interruption handler can rely on the fact that this method has completed (for example to ignore exceptions that happen after cancellation).

During graceful shutdown (for example stopping a job with a savepoint), the program must cleanly exit the SourceFunction.run(SourceContext) method soon after this method was called. The Flink runtime will NOT interrupt the source thread during graceful shutdown. Source implementors must ensure that no thread interruption happens on any thread that emits records through the SourceContext from the SourceFunction.run(SourceContext) method; otherwise the clean shutdown may fail when threads are interrupted while processing the final records.

Because the SourceFunction cannot easily differentiate whether the shutdown should be graceful or ungraceful, we recommend that implementors refrain from interrupting any threads that interact with the SourceContext at all. You can rely on the Flink runtime to interrupt the source thread in case of ungraceful cancellation. Any additionally spawned threads that directly emit records through the SourceContext should use a shutdown method that does not rely on thread interruption.

指定者:

cancel 在接口中 SourceFunction<T>