org.apache.flink.streaming.api.datastream

类 JoinedStreams<T1,T2>

java.lang.Object

org.apache.flink.streaming.api.datastream.JoinedStreams<T1,T2>

@Public
public class JoinedStreams<T1,T2>
extends Object

JoinedStreams represents two DataStreams that have been joined. A streaming join operation is evaluated over elements in a window.

To finalize the join operation you also need to specify a KeySelector for both the first and second input and a WindowAssigner.

Note: Right now, the join is being evaluated in memory so you need to ensure that the number of elements per key does not get too high. Otherwise the JVM might crash.

Example:

 
 DataStream<Tuple2<String, Integer>> one = ...;
 DataStream<Tuple2<String, Integer>> twp = ...;

 DataStream<T> result = one.join(two)
     .where(new MyFirstKeySelector())
     .equalTo(new MyFirstKeySelector())
     .window(TumblingEventTimeWindows.of(Time.of(5, TimeUnit.SECONDS)))
     .apply(new MyJoinFunction());
  

嵌套类概要

嵌套类

限定符和类型	类和说明
class	JoinedStreams.Where<KEY> Joined streams that have the key for one side defined.
static class	JoinedStreams.WithWindow<T1,T2,KEY,W extends Window> A join operation that has KeySelectors defined for both inputs as well as a WindowAssigner.

构造器概要

构造器

构造器和说明
JoinedStreams(DataStream<T1> input1, DataStream<T2> input2) Creates new JoinedStreams data streams, which are the first step towards building a streaming co-group.

方法概要

限定符和类型	方法和说明
<KEY> JoinedStreams.Where<KEY>	where(org.apache.flink.api.java.functions.KeySelector<T1,KEY> keySelector) Specifies a KeySelector for elements from the first input.
<KEY> JoinedStreams.Where<KEY>	where(org.apache.flink.api.java.functions.KeySelector<T1,KEY> keySelector, org.apache.flink.api.common.typeinfo.TypeInformation<KEY> keyType) Specifies a KeySelector for elements from the first input with explicit type information for the key type.

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

JoinedStreams

public JoinedStreams(DataStream<T1> input1,
                     DataStream<T2> input2)

Creates new JoinedStreams data streams, which are the first step towards building a streaming co-group.

参数:

input1 - The first data stream.

input2 - The second data stream.

方法详细资料

where

public <KEY> JoinedStreams.Where<KEY> where(org.apache.flink.api.java.functions.KeySelector<T1,KEY> keySelector)

Specifies a KeySelector for elements from the first input.

参数:

keySelector - The KeySelector to be used for extracting the key for partitioning.

where

public <KEY> JoinedStreams.Where<KEY> where(org.apache.flink.api.java.functions.KeySelector<T1,KEY> keySelector,
                                            org.apache.flink.api.common.typeinfo.TypeInformation<KEY> keyType)

Specifies a KeySelector for elements from the first input with explicit type information for the key type.

参数:

keySelector - The KeySelector to be used for extracting the first input's key for partitioning.

keyType - The type information describing the key type.