org.apache.flink.streaming.util

Class StreamCollector

java.lang.Object

org.junit.rules.ExternalResource

org.apache.flink.streaming.util.StreamCollector

All Implemented Interfaces:

org.junit.rules.TestRule

public class StreamCollector
extends org.junit.rules.ExternalResource

A simple utility for collecting all the elements in a DataStream.

 public class DataStreamTest {

 		{@literal @}Rule
 		public StreamCollector collector = new StreamCollector();

 		public void test() throws Exception {
 		 	StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
 		 	DataStream<Integer> stream = env.fromElements(1, 2, 3);

 		 	CompletableFuture<Collection<Integer>> results = collector.collect(stream);
 		 	Assert.assertThat(results.get(), hasItems(1, 2, 3));
 		}
 }
 

Note: The stream collector assumes: 1) The stream is bounded. 2) All elements will fit in memory. 3) All tasks run within the same JVM.

Constructor Summary

Constructors

Constructor and Description
StreamCollector()

Method Summary

Modifier and Type	Method and Description
protected void	after()
protected void	before()
<IN> CompletableFuture<Collection<IN>>	collect(DataStream<IN> stream)

Methods inherited from class org.junit.rules.ExternalResource

apply

Methods inherited from class java.lang.Object

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

Constructor Detail

StreamCollector

public StreamCollector()

Method Detail

before

protected void before()

Overrides:

before in class org.junit.rules.ExternalResource

collect

public <IN> CompletableFuture<Collection<IN>> collect(DataStream<IN> stream)

Returns:

A future that contains all the elements of the DataStream which completes when all elements have been processed.

after

protected void after()

Overrides:

after in class org.junit.rules.ExternalResource